Controllably Enriched Oxygen Vacancies through Polymer Assistance

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Controllable Richen Oxygen Vacancies through Polymer Assistance in Titanium Pyrophosphate as Super Anode of Na/K-Ion Batteries Zhongtao Li, Yunfa Dong, Jianze Feng, Tao Xu, Hao Ren, Cai Gao, Yueran Li, Mingjie Cheng, Wenting Wu, and Mingbo Wu ACS Nano, Just Accepted Manuscript • DOI: 10.1021/acsnano.9b03686 • Publication Date (Web): 07 Aug 2019 Downloaded from pubs.acs.org on August 7, 2019

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Controllable Richen Oxygen Vacancies through Polymer Assistance in Titanium Pyrophosphate as Super Anode of Na/K-Ion Batteries Zhongtao Li *, Yunfa Dong, Jianze Feng, Tao Xu, Hao Ren, Cai Gao, Yueran Li, Mingjie Cheng, Wenting Wu, Mingbo Wu * State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China *Corresponding authors. Email: [email protected](Zhongtao Li), [email protected] (Mingbo Wu)

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Abstract Although sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) show golden promising prospects as next energy storage devices, the low capacity and inferior rate capability hindered their further application. Among various phosphate-based polyanion materials, titanium pyrophosphate (TiP2O7) possesses outstanding ion transferability and electrochemical stability. However, it still has rarely been adopted as anode of SIBs/PIBs due to the poor electronic conductivity and nonreversible phase transitions. Herein, an ultra-stable TiP2O7 with enriched oxygen vacancies is prepared as SIBs/PIBs anode through P-containing polymer mediation carbonization, which avoids harsh reduction atmospheres or expensive facilities. The introduction of oxygen vacancies effectively increase pseudocapacitance, diffusivity coefficient and lower the Na insertion energy barrier. As a result, the TiP2O7 anode with enriched oxygen vacancies exhibits ultra-stable Na/K ion storage and superior rate capability. The synthetic protocol proposed here may offer a simple trail to explore advanced oxygen vacancy-type anode materials for SIBs/PIBs. Keywords: titanium pyrophosphate, oxygen vacancies, polymer assistance, pseudocapacitance, Na/K-ion Batteries

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The limited resource and fairly high expense of lithium have brought up significant problems for wide-spreading lithium-ion batteries(LIBs) in energy storage.1 While, sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) appear as promising alternatives of existing LIBs owing to the nature abundance and low price.2-4 However, the prevailing graphite-based anodes are restricted in SIBs and PIBs due to the small interlayer space between the conjugated layers.5-7 Meanwhile, the durability of alloy-type anodes, including Si,8 Sn,9 Sb,10 SnS,11 SnO,12 etc. are still far from expectation due to the larger volume variation during charging/discharging. Owning to the special coordination effects, 3D open framework and electrochemical stability, some phosphates salts have been widely used as electrolytes.13, 14 Moreover, adopting phosphate-based polyanions as SIBs and PIBs anodes would possess the following advantages: 1. rapid ion transfer to improve rate performance; 2. strong coordination effect to increase capacity; 3. 3D open framework and stable structure give rise to the durability.1,

15, 16

More specifically, TiP2O7 displays superior electrochemical

performance in aqueous SIBs and PIBs.17, 18 However, few reports adopt TiP2O7 as nonaqueous SIBs and PIBs anode, whose poor electronic conductivity and irreversible phase transitions would result in sluggish kinetics and limited capacity. 19, 20 To date, the introduction of oxygen vacancy is an effective solution to stimulate the energy storage capability of electrode through increasing reaction sites, accelerating ion transfer, delaying structural deformation and decreasing energy barrier during ions repeated insertion/extraction.21,

22

Therefore, enriching oxygen vacancies inside

TiP2O7 are expected to deliver outstanding sodium/potassium storage capacity. For 3


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example, Gan et al. reported an anatase TiO2 with plasma-induced oxygen vacancies and urchin-like appearance through H2 thermal reduction to enhance electrochemical performance for sodium storage.23 Some other methods of introducing oxygen vacancies also have been reported, including aluminothermic reduction24, electrochemical reduction25 and hydrogenation,26 etc. However, these strategies are generally limited by multiple steps, harsh reduction atmospheres or expensive facilities. Therefore, the construction of oxygen vacancies in nanohybrids through a simple and cost-effective protocol still meet great challenge. In this regard, a P-containing polymer mediated oxygen vacancies formation procedure have been developed here to avoid harsh reduction atmospheres and expensive facilities. Through co-carbonization of P-containing polymer coated TiO2/graphene oxide(GO) at elevated temperatures, the TiP2O7/carbon anode with enriched oxygen vacancies was prepared. Specially, adjusting the calcination temperature could vary the content of oxygen vacancies. As expected, the optimized composite shows advanced electrochemical stability and strong coordination capability with Na+/K+. The introduced oxygen vacancies could supply extra ion storage sites and increase pseudocapacitive charge storage capacity, which has been considered as one of the most viable and promising technologies to surmount the sluggish ion diffusion and address high-rate capacity for SIBs/PIBs.11, 27-29 Moreover, the reduced Na-insertion energy barrier through introduced oxygen vacancies is proved by the theoretical calculation. Based on above structure merits, such a composite affords large capacity, superior cyclability and excellent rate performance 4


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in sodium/potassium storage. Results and Discussion

Figure 1. The procedure of synthesizing OV-TPOs. The synthetic protocol of samples OV-TPOs are shown in Figure 1. At first, hexachlorocyclophosphazene (HCCP) and 4, 4'-sulfonyldipheno (SPO) were co-polymerized to formed a poly(cyclotriphosphazene-co-4,4’-sulfonryldiphenol) (PPS) coating on the precursor TiO2@GO, namely PPS@TiO2@GO (Figure S1a, Supporting Information, abbreviated as SI). Finally, the PPS@TiO2@GO nanohybrid was calcined at various temperatures (300 ℃, 450 ℃, 600 ℃ and 800 ℃) under N2 protection to produce OV-TPO-300, OV-TPO-450, OV-TPO-600 and OV-TPO-800, respectively.

As

a

control

sample,

another

polymer

of

the

poly(cyanuric-co-4,4’-sulfonyldiphenol) (PCS) (Figure S1b, SI) was coated on the TiO2@GO to form PCS@TiO2@GO during synthesize TiO2-PCS-600 and TiO2-PCS-800. While, the TiO2-600 was prepared through calcining TiO2 at 600 ℃ without any polymer coating.

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Figure 2 a-b. SEM of OV-TPO-600, b shows partial enlarged detail; c. TEM of OV-TPO-600; d. HRTEM of OV-TPO-600, the inset in (c) shows corresponding fast fourier transform (FFT) pattern; e. EDS elemental mapping images of Ti, P, O, and C in OV-TPO-600. The morphologies of the OV-TPO-600 were detected by scanning electron microscope (SEM) and transmission electron microscope (TEM). As shown in Figure 2a-b, uniform TiP2O7 microspheres with smooth surface were encapsulated by the folded sheets of graphene. Similar structure could be identified in SEM images of OV-TPO-800 except slightly agglomeration after calcined at higher temperature (Figure S2). While, a similar structure could be observed in the TEM images of OV-TPO-600 (Figure 2c). Besides, the high resolution image in Figure 2d shows clear 6


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lattice fringes of 0.367, 0.354 and 0.239 nm, corresponding to the (541), (630) and (490) plane of cubic TiP2O7, the inset in Figure 2c is the corresponding fast fourier transform (FFT) pattern. The EDS elemental mapping images in Figure 2e indicate that all elements are evenly distributed in OV-TPO-600.

Figure 3 a. FT-IR signal; b. XRD patterns of OV-TPO-600 and OV-TPO-800; c. Ti 2p XPS spectrum; d. O 1s XPS spectrum of OV-TPO-600; e. EPR profiles (The inset is enlarged detail of OV-TPO-800 and TiO2-PCS -600); f. ICP-MS of P content (All the data has been normalized). In the profiles of Fourier transform infrared spectra (FT-IR) (Figure 3a), the strong absorption peaks of PPS in PPS@TiO2@GO at 1100-1200 cm-1 is reduced gradually (the dash area in Figure 3a) with the increasing of calcination temperature and finally vanished at 600 ℃ due to the fully pyrolysis of polymer.30 The new absorption peaks of P-O-P bond in 1093, 929 and 789 cm-1 in the profile of OV-TPO-600 indicated the formation of pyrophosphate group.31, 32 Moreover, the absorption peak at 789 cm-1 of P-O-P bond in OV-TPO-600 has a blue shift (red dotted line in Figure 3a) compared with OV-TPO-300, which would ascribe to the decreased length of P-O bond.33, 34 As 7


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shown in X-ray powder diffraction (XRD) data, there is none diffraction peaks in OV-TPO-300, OV-TPO-450 (Figure S3a) can be observed, which indicated the amorphous structure. When the calcination temperature increased up to 600 ℃ and 800 ℃, some obviously crystalline diffraction peaks of TiP2O7 crystal (PDF#38-1468) could be identified in Figure 3b. Moreover, the diffraction peaks of OV-TPO-800 are much sharper and stronger than that of OV-TPO-600, which indicated the crystallized TiP2O7 at higher temperature. If P-containing polymer is replaced or removed, the diffraction profiles of TiO2-PCS-600 and TiO2-600 are well consistent with that of TiO2 nanocrystal (Figure S3a). In Figure S3b, the overall XPS spectrum indicated the existence of Ti, P, O, C, N and S. The core level C 1s spectrum (Figure S4a) can be divided into three peaks ascribed to the C-C (284.8 eV), C-O (285.8 eV), and HO-C=O (288.9 eV).

35

In the

high resolution of the N 1s spectrum (Figure S4b), the two peaks centered at 399.1 eV and 400.8 eV belongs to the pyridinic-N and graphitic-N, respectively.7, 36 C-S (163.4 eV), S-S (164.5 eV), and C-SOx (168.2 eV) can be deconvoluted in the high resolution of the S 2p spectrum (Figure S4c).37,

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The content of N and S in

OV-TPO-600 is 1.4 and 0.38 at. %, respectively. High resolution images of Ti 2p of OV-TPO-600 and OV-TPO-800 is shown in Figure 3c. Ti 2p of OV-TPO-800 move to the higher binding energy compared with OV-TPO-600, which revealed the decreasing of electron cloud due to the deeper pyrolysis, this would deteriorate the ability of attracting sodium/potassium ions.39-41 The high resolution images of O 1s of OV-TPO-600 in Figure 3d indicated P-O-P peak at around 533.36 eV and P-O-Ti 8


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peak at about 532.06 eV,42 while the deconvoluted peak at 530.98 eV in OV-TPO-600 and 531.3 eV in OV-TPO-450 (Figure S5a) demonstrates the existence of oxygen vacancy (the concrete data is shown in Table S1).40, 43 Furthermore, only Ti-OH peaks could be deconvoluted out from OV-TPO-300 without any peak of oxygen vacancies (Figure S5b),44 which would duo to the unreacted titanium hydroxide and partial decomposed and melted PPS coating on surface. However, some oxygen vacancies are starting to be generated inside the OV-TPO-300 as shown in electron paramagnetic resonance (EPR) data (Figure 3e). Finally, there is no oxygen vacancies can be deconvoluted in profile of OV-TPO-800 (Figure S5c), which would due to the recrystallization of titanium pyrophosphate. To further understanding the oxygen vacancy, Figure 3e and Figure S6 displays the electron paramagnetic resonance (EPR) spectra of six samples, all of which shows a similar signal at g = 2.005 ,which is ascribe to oxygen vacancy (VO).23,

44

In general, the peak value of VO is increased

gradually with the increasing of annealing temperature and reach the maximum in OV-TPO-450 with pyrolysis of PPS coating. After annealed at 800 ℃, only tiny amount of oxygen vacancies could be detected in OV-TPO-800 due to the aggregation and recrystallization. The content of oxygen vacancies also could be verified by the XPS results. The PPS coating seems play positive roles on the formation of oxygen vacancies.45 The oxygen vacancy could hardly be identified in TiO2-PCS-600 and TiO2-PCS-800, which would due to the absence of PPS coating (Figure 3e and Figure S6). To further understanding the roles of polymer PPS on generation oxygen vacancies 9


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at elevated temperature, the variation of contents of P have been studied by inductively coupled plasma mass spectrometry (ICP-MS) in Figure 3f. With the increasing of heating temperature from 300 ℃ to 600 ℃, P and C from PPS gradually convert to phosphate and CO2.30 The content of P is decreased rapidly, which ascribes to the decomposition of PPS and phosphate, which could take away the oxygen from TiO2 to produce oxygen vacancies. Moreover, the P-O-P bond would be partly reduced to produce oxygen vacancies. As the result, oxygen vacancies are generated and became highest at 450 ℃. When the temperature increased over 600 ℃, the stability of reserved P-containing groups is increased and the content of P is decreased slightly, which would slow down the generation of oxygen vacancies and speed up the vanishment through restoring process during recrystallization. As the result, the content of oxygen vacancy in OV-TPO-800 is obviously decreased. The effect of pyrolysis temperature is further studied by Ramans, N2 adsorption/desorptions and thermogravimetric analysises (TGA). Figure S7a shows the Raman spectras of OV-TPO-300, OV-TPO-450, OV-TPO-600, and OV-TPO-800. All of them exhibit two characteristic peaks around 1355 and 1586 cm-1, related to the D-band and G-band of carbon.46 At lower pyrolysis temperature, the low ID/IG ratios of OV-TPO-300 (0.88) and OV-TPO-450 (0.87) revealed more disordered carbon. Meanwhile, the weight losses from TGA datas (Figure S7b) of OV-TPO-300 and OV-TPO-450 are both high (71.7% and 60.5%, respectively), all of which indicated low degree of carbonization. At higher pyrolysis temperature, the ID/IG values in Raman spectra (0.92 and 0.91) and the weight losses (29.2% and 25.5%) from TGA 10


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datas in Figure S7b supposed the higher carbonization degree of OV-TPO-600 and OV-TPO-800. Moreover, The BET surface areas of the OV-TPO-600 (20.2 m2 g-1) are close to that of OV-TPO-800 (14.3 m2 g-1). The pore-size distributions of the two samples are also similar, which are composed by the microporous and mesoporous (Figure S8a-b).

Figure 4. a. Cyclic voltammograms (CV) of OV-TPO-600 in PIBs at a scan rate of 0.2 mV s−1; b. Capacity/Potential profile of OV-TPO-600 at current density of 100 mA g−1 in PIBs; c. Galvanostatic charge and discharge curves of OV-TPO-600 in PIBs at current density of 100 mA g-1 ; Rate capabilities of OV-TPO-600 in d)SIBs and e)PIBs; f. Charge/discharge proﬁles of OV-TPO-600 at various rates in PIBs; Long-period cycling capability of OV-TPO-600, OV-TPO-800 and TiO2-PCS-600 at current density of 1000 mA g-1 in g) SIBs and h) PIBs. The electrochemical properties of OV-TPO-600 as the anode of SIBs and PIBs were tested by assembling coin-type cells with metal Na and K as the counter electrodes, respectively. In the first scan as SIB’s anode (Figure S9a), a cathodic peak at 0.85 V and 0.73 V can be attributed to the generation of the solid electrolyte 11


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interface (SEI) film and decomposition of electrolyte, which disappear in the subsequent cycles.

15

Meanwhile, a broad anodic peak at around 1.9 V could be

correlated with Na ion extraction from OV-TPO-600. After the first cycle, there is only an obvious anodic peak at 1.9 V which ascribed to the Na-extraction process. While, the broad cathodic peak between 0.5-1.75V could attribute to the Na+ insertion to the OV-TPO-600 and result in a high pseudocapacitive, which would be indicated large amount of easy-to-access surface-redox reactive sites to facilitate ion and charge transfer. Moreover, the voltage curves in the galvanostatic charge-discharge (GCD) curves (Figure S9b) are consistent with the CV. After cycling six times, the charge and discharge curves are superimposed with the others and deliver a highest reversible discharge capacity (271.1 mAh g−1) among the titanium-based composites in state-of-the-art (Table S2, SI). In Figure S9c, the electrode maintains a high capacity reservation of 82.2% after 100 cycles (according to charge capacity in the 6th cycle) in SIBs due to the enriched oxygen vacancies. The electrochemical properties of OV-TPO-600 as the negative electrode for PIBs is similar as that of SIBs. In Figure 4a, the first discharge process shows a small peak at 0.5 V and a sharp slope down to 0.01 V, indicating the growth of the SEI film and the K-ion intercalation in OV-TPO-600. The cycling profile of second cycle is overlapped with the third cycle, which indicates the high invertibility of the K-ion storage procedure. Figure 4b shows 1st, 2nd, 30th, 50th charge/discharge profiles of OV-TPO-600 at 100 mA g-1. Generally, the features of the charge/discharge profiles are well coincide with those of the CV curves where the first discharge and charge specific capacities are 638.3 and 12


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298.3 mAh g-1, respectively. Figure 4c exhibits the cycling capability of OV-TPO-600 at 100 mA g-1, it retained 299.3 mAh g-1 potassium storage capacity after 100 cycles running with a superior capacity retention of 91.5% based on the second cycle. Figure 4d-f and Figure S9d compares the rate capability of OV-TPO-600 anodes in SIBs and PIBs in the potential range of 0.01–3 V with varied current densities from 0.1 to 5 A g-1. The 124.9 mAh g-1 reversible capacity can be reached at 5 A g-1, which recovers back to 239.9 mAh g-1 with the decreasing of current density to 0.1 A g-1. Considering the rate performance of OV-TPO-600 in PIBs, the nanohybrids shows high reversible capacity of 342.6, 288.4, 238.8, 205.7, 174.6, 154.4 and 138.9 mAh g-1 with the current density at 0.1, 0.2, 0.5, 1, 2, 3 and 5 A g-1 (Figure 4e and Figure 4f). The introduction of oxygen vacancies seems effectively accelerate ion transfer and eventually promote the rate performance of OV-TPO-600. Meanwhile, the doping of N, S into the carbon matrix also have positive effects on the rate performance through increasing the electrical conductivity.7, 36 The charge transfer resistance and diffusion kinetics of Na-ion was further explored by in situ EIS, from which impedance spectra were tested during the discharging. The operation potentials were 1.9, 1.4, 1.1, 0.7 and 0.4 V, and the Rct and RNa values was obtained by matching the EIS spectra to an equivalent circuit (Figure S10).47-49 As shown in Figure S11 and Figure S12, the interfacial charge transfer resistances (Rcts) of OV-TPO-600, OV-TPO-800 and TiO2-PCS-600 were almost independent of operation potentials in SIBs, among which the Rct values of OV-TPO-600 were obviously lower than the other samples (Figure S12a). The experiment datas revealed that the Na-ion was 13


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easier to insert into the TiP2O7 at the interface in OV-TPO-600. The bulk diffusion resistance RNa (Figure S12b) were slightly varied on the potentials, OV-TPO-600 still possess the minimum diffusion resistance among the four samples, which imply that the kinetic limitation associated with Na-ion diffusion from interface into lattice was relieved more effectively in OV-TPO-600 than in other control samples.50 Moreover, these results are consistent with the Galvanostatic Intermittent Titration Technique (GITT) results (Figure 5d). Besides, the EIS spectra of OV-TPO-300, OV-TPO-450, OV-TPO-600 and OV-TPO-800 after 10 cycles at the potential of 1.9 V in SIBs were measured in Figure S13. The much lower conductivity of OV-TPO-300 and OV-TPO-450 due to lower degree of carbonization and pyrolysis at 450 ℃ or even lower temperature, which would attribute to deteriorate Na/K storage performances. Inspired by the excellent rate property of OV-TPO-600, the long-period cycling stability as anode of SIBs and PIBs were measured at the current densities of 1000 mA g-1 (Figure 4g and 4h), respectively. The OV-TPO-600 anode in SIBs sustained a discharge capacity of 215.5 mAh g-1 after 6000 cycles (98.5% capacity of the second cycles). Furthermore, the cycling capability for rapid potassium ion storage is also superior (177.2 mAh g-1 after 5300 cycles) to the previous reports (Table S3, SI). Moreover, the initial coulombic efficiency of OV-TPO-600 is 53.5% at the current density of 1000 mA g-1 in SIBs, while in PIBs is 46.7%. The higher initial coulombic efficiency in SIBs would due to the smaller Na-ion than that of K-ion, which attribute to accelerated diffusion kinetic as shown in the GITT test (Figure 5d).1, 51, 52 While, the obvious lower capacities of OV-TPO-800, TiO2-PCS-600 and TiO2-PCS-800 14


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(Figure 4g, 4h and Figure S14a, 14b) would due to the decreased active sites for sodium/potassium storage without oxygen vacancies.53 Although the content of oxygen vacancies in OV-TPO-450 and OV-TPO-300 is higher, the poorer conductivity lower their reversible capacities. CV measurements of OV-TPO-600 and OV-TPO-800 at different scan rates (from 0.2 to 8 mV s-1) were adopted to evaluate electrochemical kinetics of the designed electrodes in SIBs and PIBs in Figure S15a-c (details of calculation are shown in SI), which could be divided into pseudocapacitive process and diffusion-controlled process. In SIBs, a number of b values between 0.65-0.85 are extracted by drawing up the fitting oblique lines of log (i) and log (v) at various voltages of the discharge process (inset in Figure 5a), which indicates the mixed pseudocapacitance and diffusion-controlled processes for the Na storage in OV-TPO-600. As shown in Figure 5a, the pseudocapacitance contributes 73.6% capacity at a scan rate of 2 mV s-1 and then increases to 93.2% with increasing of the scan rate to 8 mV s-1(Figure S15d). Similarly, the calculated b values of the different voltages in PIBs are between 0.5 and 1 (inset in Figure 5b), which also demonstrates a mixed pseudocapacitance and diffusion-controlled process for potassium storage. The pseudocapacitance contribute 66.5% (Figure 5b) capacity at a scan rate of 2 mV s-1 which is lower than in SIBs. A comparison of pseudocapacitance contribution of the OV-TPO-600 and OV-TPO-800 in PIBs are shown in Figure 5c, the pseudocapacitive contributions of OV-TPO-600 are increased from 33.2% to 92.9% with the scan rate varied from 0.2 to 8 mV s-1. While, the pseudocapacitive contributions of OV-TPO-800 is still as low as 51.4% 15


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even scan at 8 mV s-1. Due to the similar textural characterizations between OV-TPO-600

and

OV-TPO-800

through

Ramans,

TGAs

and

N2

adsorption/desorptions, the distinct pseudocapacitive character is supposed to derive from the variation of oxygen vacancies inside the materials. Therefore, the pseudocapacitance plays a dominated role during storaging Na/K in OV-TPO-600, which indicated that Na+/K+ are proned to be stored on the superficial district of the composite. The pseudocapacitive behavior could greatly alleviate the structural damage during cycling and result in excellent durability;11,

54

and additionally

accelerate electron transfer and shorten ion transport distance to reach higher rate performance.28, 55

Figure 5. Pseudocapacitive contributions at a scan rate of 2 mV s-1 represented by the violet region. The inset is b values correlated with battery voltages of OV-TPO-600 for cathodic scans in a) SIBs, b) PIBs; c. Comparison of pseudocapacitance contribution ratios of the OV-TPO-600 and OV-TPO-800 in PIBs; d. The charge/discharge profiles in GITT test of OV-TPO-600 and the corresponding 16


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diffusivity coefficient (D) of K+ in the discharge/charge processes of the OV-TPO-600 and OV-TPO-800 in the second and third cycles in PIBs. The Galvanostatic Intermittent Titration Technique (GITT) measurements were used to evaluate the kinetics of Na+/K+ solid-state diffusion in the lattice of OV-TPO-600 and OV-TPO-800 during cycling (details of calculation is shown in SI). The charge/discharge profiles and corresponding diffusion coefficients of Na+/K+ (D) in GITT test for OV-TPO-600 electrodes in the second and third cycles are shown in Figure S17 and Figure 5d. The DNa value is range from 0.62×10-7 to 4.15×10-7 cm2 s-1 during the two discharge processes and range from 0.39×10-7 to 1.20×10-7 cm2 s-1 (Figure S17) during charge processes. While the DK value is range from 0.47×10-7 to 1.82×10-7 cm2 s-1 during the two discharge processes and range from 0.27×10-7 to 0.78×10-7 cm2 s-1 (Figure 5d) during charge processes. The diffusion coefficient of Na+ is higher than K+, which results in the higher Na+ transfer speed and more pseudocapacitance effect in SIBs. In addition, the diffusion coefficient of K+ in OV-TPO-800 is smaller than that in OV-TPO-600 (Figure 5d), which deteriorates the capacity and rate performance of OV-TPO-800. Furthermore, OV-TPO-600 also reflects a higher diffusion coefficient (DNa) than other previous reports,

1, 56, 57

which

benefits from the enriched oxygen vacancies and optimized nanostructure. The high symmetry of discharge/charge curves in GITT also indicated a highly reversible Na/K storage process. To illustrate the function of oxygen vacancies on the Na-insertion performance, the energy barrier of the Na-insertion process (△E

insert)

of TiP2O7 and OV-TiP2O7 were

17


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analyzed through density functional theory (DFT) calculations, which is calculated by utilizing the following equation.58, 59 ∆𝐸𝑖𝑛𝑠𝑒𝑟𝑡 = 𝐸𝑖𝑛𝑠𝑒𝑟𝑡 ― 𝑇𝑖𝑃2𝑂7 ― (𝐸𝑇𝑖𝑃2𝑂7 + 𝐸𝑁𝑎) where 𝐸𝑖𝑛𝑠𝑒𝑟𝑡 ― 𝑇𝑖𝑃2𝑂7, 𝐸𝑇𝑖𝑃2𝑂7, 𝐸𝑁𝑎 represent the total energy of Na-inserted TiP2O7, TiP2O7 and Na+, respectively. Figure 6a and 6b exhibits the structure of Na-inserted TiP2O7 and Na-inserted OV-TiP2O7, respectively (the other two possible models of oxygen vacancies in Figure S18a and 18b were collapsed during optimization). The obtained 𝐸𝑖𝑛𝑠𝑒𝑟𝑡 ― 𝑇𝑖𝑃2𝑂7, 𝐸𝑇𝑖𝑃2𝑂7, 𝐸𝑁𝑎 and ∆𝐸𝑖𝑛𝑠𝑒𝑟𝑡 for each model are shown in Table 1. The OV-TiP2O7 with the introduction of oxygen vacancies possesses lower Na-insertion energy barriers (-2.275eV) than that of TiP2O7 (-1.762eV), which suggested that Na+ is more energetically favorable for intercalation into OV-TiP2O7. To exhibit the evolution of the morphological characteristics of the electrodes after long-time cycles, ex-situ SEMs of the electrodes were adopted. The spheroid-like appearance can be sustained after 6000 cycles in SIBs (Figure S19a) and also keeped after 5300 cycles in PIBs (Figure S19b), which demonstrated the outstanding robust structure. As shown in Figure S20, the EPR spectrum after cycling still prove the existence of oxygen vacancies, which increased slightly than the uncycled counterpart. Moreover, the O 1s spectra of desodiated OV-TPO-600 in Figure S21a still could be deconvoluted into P-O-Ti and oxygen vacancy, but the peak of P-O-P cannot be deconvoluted after long-term cycles. The P-O-P bonds exhibited lower stability compared with other chemical bonds in titanium pyrophosphate, which could be reduced by PPS at elevated temperature and converted to oxygen vacancies as shown in DFT calculation (Figure 6). In the point of this view, the P-O-P also would be partly reduced during charging/discharging. Besides, a newly formed peak at 535.45 18


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eV is originated from the formation of SEI.30 The XPS results also imply that the oxygen vacancy is slightly increased after 6000 times cycling (Figure S21a). While, the XRD profile of OV-TPO-600 after cycling (Figure S22) include the diffraction peaks of titanium pyrophosphate as initial. Furthermore, the Ti 2p signal after cycling was showed in Figure S21b, which is consistent with initial data. Herein, all the data indicated that both the chemical structure of composite and oxygen vacancies could be keep stable during cycling.

Figure 6. Structure models of a)Na-inserted TiP2O7 and b)Na-inserted OV-TiP2O7. Table 1. Calculated 𝐸𝑖𝑛𝑠𝑒𝑟𝑡 ― 𝑇𝑖𝑃2𝑂7/eV, 𝐸𝑇𝑖𝑃2𝑂7/eV, 𝐸𝑁𝑎/eV and ∆𝐸𝑖𝑛𝑠𝑒𝑟𝑡 /eV per unit cell for TiP2O7 and OV-TiP2O7.

𝐸𝑖𝑛𝑠𝑒𝑟𝑡 ― 𝑇𝑖𝑃2𝑂7/eV

𝐸𝑇𝑖𝑃2𝑂7/eV

𝐸𝑁𝑎/eV

∆𝐸𝑖𝑛𝑠𝑒𝑟𝑡/eV

TiP2O7

-318.611

-315.417

-1.432

-1.762

OV-TiP2O7

-310.010

-306.303

-1.432

-2.275

Structure

Conclusion In conclusion, an ultra-long cycling stability of SIBs/PIBs anodes were achieved through calcination a P-containing polymer coated TiO2/GO nanohybrids to enrich 19


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oxygen vacancies inside titanium pyrophosphate in a controllable manner. Our synthesis strategy overcomes most of stringent requirements during forming oxygen vacancies. The excellent specific capacity, outstanding durability and superior rate capability of optimized anode can be attributed to the favorable synergetic effects: Firstly, the introduction of oxygen vacancies could reduce the Na-insertion energy barrier and increase pseudocapacitive behavior, which is in favor of charge/ion transfer as the GITT exhibited. Secondly, the incorporated carbon matrix can play a significant role in enhancing the electrical conductivity and mitigating the volume change effectively during cycling. Considering the facile synthesis process, the enriched oxygen vacancies composite manifests a prospective anode for SIBs and PIBs. Furthermore, achieving a tunable pseudocapacitance by the oxygen vacancies also provide a reference for exploring energy storage mechanism. Methods All the raw materials used in the synthesis processes were of analytical grade purity and were used as the initial state. Materials synthesis Synthesis of TiO2@GO: Graphite oxide (GO) was produced by optimized Hummers method refering to the previous report.60TiO2 particles are riveted on the GO nanosheets by a facile vigorous stirring way. In a classical protocol, the above fabricated GO (90 mg) was firstly decentralized in 100 mL absolute ethyl alcohol and ultrasonic for 30 min. Then added 0.64 g hexadecylamine (HDA) and ultrasonic for 20


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10 min. Then, 1 ml NH3·H2O was added to the above dispersion liquid and blent for 10 min. Then, 0.9 ml tetra-n-butyl titanate (TNBT, 97%) was added to the solution and vigorous stirred for another 10 min. The obtained solution denoted as TiO2@GO. Synthesis of PPS@TiO2@GO: 0.9 g hexachlorocyclophosphazene (HCCP) and 0.6 g 4, 4'-sulfonyldiphenol dissolved in 15 mL of absolute ethyl alcohol was poured to the above TiO2@GO mixture. After blending for 10 minutes, 4 mL of triethylamine was added dropwisely and the mixture continued to be stirred for another 24 h at 35 ℃. Then, the gray precipitates were collected by centrifugation and rinsed by absolute ethyl alcohol for 3 times and dried under vacuum at 30 ℃ for 10 h. The obtained product was named as PPS@TiO2@GO. Synthesis of OV-TPOs: The above PPS@TiO2@GO was calcined at 600 ℃ for 3 h in a tubular furnace with nitrogen protection by a heating rate of 3 ℃/min to gain the final composite named as OV-TPO-600. For comparison, the calcination temperature is changed to 300, 450 and 800 ℃, the final product was denoted as OV-TPO-300, OV-TPO-450 and OV-TPO-800, respectively. Fabrication of PCS@TiO2@GO: The synthesis procedure is similar to the procedure

of

fabricating

PPS@TiO2@GO

except

substitute

of

hexachlorocyclophosphazene (HCCP) with cyanuric trichloride (CTC). Synthesis of TiO2-PCS-600 and TiO2-PCS-800: The above PCS@TiO2@GO was annealed at 600 and 800 ℃ for 3h in a tubular furnace with nitrogen protection by a heating rate of 3 ℃/min to gain the final composite named as TiO2-PCS-600 and TiO2-PCS-800.

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Structural Characterization X-ray powder diffraction (XRD) is utilizing an X-ray diffractometer (X’Pert PRO MPD, Holland) with Cu Kα radiation (λ = 1.518 Å). Scanning electron microscope (SEM) and transmission electron microscope (TEM) were carried out on SEM, Hitachi S-4800 and JEM-2010 system at 220 Kv, respectively. X-ray photoelectron spectroscopy (XPS, Thermo Scientific Escalab 250XI) with Mg Kα radiation was applied to analyze the chemical composition. PerkinElmer spectrum GX FTIR system to produced the Fourier transform infrared spectra (FI-TR). Electron paramagnetic resonance (EPR) (Bruker EMX-10/12, 100 kHz and 298 K) coupled with Inductively coupled plasma mass spectrometry (ICP-MS, Agilent 7700x ICP-MS). Raman (Jobin-Yvon

Labram-010)

along

with

N2

adsorption-desorption

analysis

(Micromeritics ASAP2020) to test the carbon characteristics and content. Electrochemical measurements CR2032-type coin half cells utilize pure Na/K foil as the counter electrode were packaged in an argon-filled glove box to evaluate electrochemical performance. The as-obtained active materials (80 wt%), Super P (10 wt%) and poly(vinylidene fluoride) in N-methyl-2-pyrrolidinone solvent were blending to gain a homogeneous slurry. And the mixture was then casted on copper foil and dried in a vacuum oven at 80 °C for 12 h to fabricate the working electrodes. The mass loading was 1.15-1.55 mg cm−2 and 0.98−1.3 mg cm−2 on each electrode for SIBs and PIBs, respectively (The specific capacity was calculated based on the mass of whole nanohybrid), 1 M NaClO4 in ethylene carbonate/diethyl carbonate (the volme ratio is 1:1) with 5 wt % 22


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fluoroethylene carbonate is made as the sodium ion electrolyte. The potassium ion electrolyte used was a 0.8 M KPF6 in a mixed solution of ethylene carbonate and diethyl carbonate (1:1;v/v). The galvanostatic discharge/charge test was carried on a multichannel battery measuring system (LAND CT2001A) with a potential range of 0.01–3V. Cyclic voltammetries (CV) at a scan rate of 0.2-8 mV s-1 were carried on CHI760e electrochemical workstation. Gamry 30115 electrochemical workstation was used to measure the in situ electrochemical impedance spectroscopy (EIS) during discharging at various voltages with frequencies of 5 mHz to 100 kHz. EIS was measured after three CV cycles to enable quasi-reversible conditions. All of the tests were performed at 25 ℃. DFT calculations Our calculations are executed by employing the Vienna versus Simulation Package (VASP) according to density functional theory (DFT).61 The exchange-correlation is described by Perdew-Burke-Ernzerhof (PBE).62 The projected augmented wave (PAW) potential is utilized to describe the electron-ion interactions.63 The plane-wave cutoff energy is set to 500 eV. All geometric structures are entirely relaxed until energy is converging to 10-6 eV and the convergence tolerance of force on each atom is less than 0.01 eV/Å. The DFT-D3 method is adopted in all calculations, which proposed by Grimme to correct the adsorption energy by treating dispersion interactions.64 The Brillouin zone is sampling of 5×5×5 Gamma k-point grid is used to perform geometric optimization. We use unit cell of TiP2O7 crystal to conduct our study. 23


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Associated content Supporting Information Available: This material is available free of charge via the Internet at http://pubs.acs.org. Details about the corresponding figures and analysis (SEM, XRD, XPS, EPR, Raman spectra, TGA, N2 adsorption-desorption isotherms, electrochemical results, equivalent circuit) on obtained products and contrast samples, the other cases of DFT and three tables showing the concrete XPS results and the surveies of Ti-based anode materials in SIBs and PIBs.

The authors declare no competing financial interest. Author information: Corresponding Author *E-mail: [email protected]. *E-mail: [email protected]. ORCID Zhongtao Li: 0000-0003-0157-6098 Yunfa Dong: 0000-0003-1349-0726 Jianze Feng: 0000-0003-4383-6003 Tao Xu: 0000-0001-8166-4703 Hao Ren: 0000-0001-9206-7760 Cai Gao: 0000-0001-5923-6112 Yueran Li: 0000-0003-1566-5227 24


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Mingjie Cheng: 0000-0001-9123-757X Wenting Wu: 0000-0002-8380-7904 Mingbo Wu: 0000-0003-0048-778X

Acknowledgements This work was financially supported by the National Natural Science Foundation of China (Grant Nos. 21572269, 21502227 and 51873231), and the Fundamental Research Funds for the Central Universities (17CX05015, 15CX08005A), the Financial Support from Taishan Scholar Project, the Key Research and Development Program of Shandong Province, China (2017GGX40118).

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References: (1) Wei, Z.; Wang, D.; Li, M.; Gao, Y.; Wang, C.; Chen, G.; Du, F. Fabrication of Hierarchical Potassium Titanium Phosphate Spheroids: A Host Material for Sodium-Ion and Potassium-Ion Storage. Adv. Energy Mater. 2018, 8 , 1801102. (2) Chayambuka, K.; Mulder, G.; Danilov, D. L.; Notten, P. H. L. Sodium-Ion Battery Materials and Electrochemical Properties Reviewed. Adv. Energy Mater. 2018, 8, 1800079. (3) Yang, J.; Xiao, X.; Gong, W.; Zhao, L.; Li, G.; Jiang, K.; Ma, R.; Rummeli, M. H.; Li, F.; Sasaki, T.; Geng, F. Size-Independent Fast Ion Intercalation in Two-Dimensional Titania Nanosheets. Angew. Chem. Int. Ed. 2019,58,8470-8475. (4) Palomares, V.; Serras, P.; Villaluenga, I.; Hueso, K. B.; Carretero-González, J.; Rojo, T. Na-Ion Batteries, Recent Advances and Present Challenges to Become Low Cost Energy Storage Systems. Energy Environ. Sci. 2012, 5 , 5884-5901. (5) Li, W.; Zhou, M.; Li, H.; Wang, K.; Cheng, S.; Jiang, K. A High Performance Sulfur-Doped Disordered Carbon Anode for Sodium Ion Batteries. Energy Environ. Sci. 2015, 8 , 2916-2921. (6) Shuai, H.; Ge, P.; Hong, W.; Li, S.; Hu, J.; Hou, H.; Zou, G.; Ji, X. Electrochemically Exfoliated Phosphorene-Graphene Hybrid for Sodium-Ion Batteries. Small Methods 2019, 3, 1800328. (7) Huang, S.; Li, Z.; Wang, B.; Zhang, J.; Peng, Z.; Qi, R.; Wang, J.; Zhao, Y. N-Doping and Defective Nanographitic Domain Coupled Hard Carbon Nanoshells for High Performance Lithium/Sodium Storage. Adv. Funct. Mater.2018, 28, 1706294. (8) Song, Y.; Zuo, L.; Chen, S.; Wu, J.; Hou, H.; Wang, L. Porous Nano-Si/Carbon Derived from Zeolitic Imidazolate Frameworks@Nano-Si as Anode Materials for Lithium-Ion Batteries. Electrochim. Acta 2015, 173, 588-594. (9) Qin, J.; He, C.; Zhao, N.; Wang, Z.; Shi, C.; Liu, E.-Z.; Li, J. Graphene Networks Anchored with Sn@Graphene as Lithium Ion Battery Anode. ACS Nano 2014, 8, 1728–1738. (10) Yi, Z.; Han, Q.; Zan, P.; Wu, Y.; Cheng, Y.; Wang, L. Sb Nanoparticles Encapsulated into Porous Carbon Matrixes for High-Performance Lithium-Ion Battery Anodes. J. Power Sources 2016, 331, 16-21. (11) Chao, D.; Zhu, C.; Yang, P.; Xia, X.; Liu, J.; Wang, J.; Fan, X.; Savilov, S. V.; Lin, J.; Fan, H. J.; Shen, Z. Array of Nanosheets Render Ultrafast and High-Capacity Na-ion Storage by Tunable Pseudocapacitance. Nat. Commun. 2016, 7, 12122. (12) Zhang, F.; Zhu, J.; Zhang, D.; Schwingenschlogl, U.; Alshareef, H. N. Two-Dimensional SnO Anodes with a Tunable Number of Atomic Layers for Sodium Ion Batteries. Nano Lett. 2017, 17, 1302-1311. (13) Hallopeau, L.; Bregiroux, D.; Rousse, G.; Portehault, D.; Stevens, P.; Toussaint, G.; Laberty-Robert, C. Microwave-Assisted Reactive Sintering and Lithium Ion Conductivity of Li1.3Al0.3Ti1.7(PO4)3 Solid Electrolyte. J. Power Sources 2018, 378, 48-52. (14) Dunstan, M. T.; Halat, D. M.; Tate, M. L.; Evans, I. R.; Grey, C. Variable-Temperature Multinuclear Solid-State NMR Study of Oxide Ion Dynamics in Fluorite-Type Bismuth Vanadate and Phosphate Solid Electrolytes. Chem. Mater. 2019, 31, 1704-1714. (15) Wang, D.; Liu, Q.; Chen, C.; Li, M.; Meng, X.; Bie, X.; Wei, Y.; Huang, Y.; Du, F.; Wang, C.; Chen, G. NASICON-Structured NaTi2(PO4)3@C Nanocomposite as the 26


Page 26 of 30

Page 27 of 30 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

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Low Operation-Voltage Anode Material for High-Performance Sodium-Ion Batteries. ACS Appl. Mater. Interfaces 2016, 8, 2238-2246. (16) Zhang, Z.; Li, M.; Gao, Y.; Wei, Z.; Zhang, M.; Wang, C.; Zeng, Y.; Zou, B.; Chen, G.; Du, F. Fast Potassium Storage in Hierarchical Ca0.5Ti2(PO4)3@C Microspheres Enabling High-Performance Potassium-Ion Capacitors. Adv. Funct. Mater. 2018, 28, 1802684. (17) Yee, G.; Shanbhag, S.; Wu, W.; Carlisle, K.; Chang, J.; Whitacre, J. TiP2O7 Exhibiting Reversible Interaction with Sodium Ions in Aqueous Electrolytes. Electrochem. Commun. 2018, 86, 104-107. (18) Wen, Y.; Chen, L.; Pang, Y.; Guo, Z.; Bin, D.; Wang, Y. G.; Wang, C.; Xia, Y. TiP2O7 and Expanded Graphite Nanocomposite as Anode Material for Aqueous Lithium-Ion Batteries. ACS Appl. Mater. Interfaces 2017, 9 , 8075-8082. (19) Rai, A. K.; Gim, J.; Song, J.; Mathew, V.; Anh, L. T.; Kim, J. Electrochemical and Safety Characteristics of TiP2O7–Graphene Nanocomposite Anode for Rechargeable Lithium-Ion Batteries. Electrochim. Acta 2012, 75, 247-253. (20) Hu, Q.; Liang, J.-Y.; Liao, J.-Y.; Tang, Z.-F.; Ding, X.; Chen, C. A Comparative Study on Nanocrystalline Layered and Crystalline Cubic TiP2O7 for Rechargeable Li/Na/K Alkali Metal Batteries. J. Mater. Chem. A 2018, 6, 15230-15236. (21) Wang, Y.; Xiao, X.; Li, Q.; Pang, H. Synthesis and Progress of New Oxygen-Vacant Electrode Materials for High-Energy Rechargeable Battery Applications. Small 2018, 14 , 1802193. (22) Wang, Y.; Zhang, R.; Chen, J.; Wu, H.; Lu, S.; Wang, K.; Li, H.; Harris, C. J.; Xi, K.; Kumar, R. V.; Ding, S. Enhancing Catalytic Activity of Titanium Oxide in Lithium–Sulfur Batteries by Band Engineering. Adv. Energy Mater. 2019, 1900953. (23) Gan, Q.; He, H.; Zhao, K.; He, Z.; Liu, S.; Yang, S. Plasma-Induced Oxygen Vacancies in Urchin-Like Anatase Titania Coated by Carbon for Excellent Sodium-Ion Battery Anodes. ACS Appl. Mater. Interfaces 2018, 10, 7031-7042. (24) Lin, T.; Yang, C.; Wang, Z.; Yin, H.; Lü, X.; Huang, F.; Lin, J.; Xie, X.; Jiang, M. Effective Nonmetal Incorporation in Black Titania with Enhanced Solar Energy Utilization. Energy Environ. Sci.2014,7, 967-972. (25) Wang, G.; Yang, Y.; Ling, Y.; Wang, H.; Lu, X.; Pu, Y.-C.; Zhang, J. Z.; Tong, Y.; Li, Y. An Electrochemical Method to Enhance the Performance of Metal Oxides for Photoelectrochemical Water Oxidation. J. Mater. Chem. A 2016, 4, 2849-2855. (26) Chen, X.; Liu, L.; Yu, P. Y.; Mao, S. Increasing Solar Absorption for Photocatalysis with Black Hydrogenated Titanium Dioxide Nanocrystals. Science 2011, 331, 746-750. (27) Shen, L.; Lv, H.; Chen, S.; Kopold, P.; van Aken, P. A.; Wu, X.; Maier, J.; Yu, Y. Peapod-Like Li3VO4/N-Doped Carbon Nanowires with Pseudocapacitive Properties as Advanced Materials for High-Energy Lithium-Ion Capacitors. Adv. Mater. 2017, 29,1700142. (28) He, H.; Huang, D.; Tang, Y.; Wang, Q.; Ji, X.; Wang, H.; Guo, Z. Tuning Nitrogen Species in Three-Dimensional Porous Carbon via Phosphorus Doping for Ultra-Fast Potassium Storage. Nano Energy 2019, 57, 728-736. (29) Feng, J.; Dong, Y.; Yan, Y.; Zhao, W.; Yang, T.; Zheng, J.; Li, Z.; Wu, M. Extended Lattice Space of TiO2 Hollow Nanocubes for Improved Sodium Storage. Chem. Eur. J. 2019, 373, 565-571. (30) Li, Z.; Feng, J.; Hu, H.; Dong, Y.; Ren, H.; Wu, W.; Hu, Z.; Wu, M. An Amorphous Tin-based Nanohybrid for Ultra-Stable Sodium Storage. J. Mater. Chem. A 2018, 6, 18920-18927. 27


ACS Nano 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(31) Iwase, M.; Yamada, K.; Kurisaki, T.; Prieto-Mahaney, O. O.; Ohtani, B.; Wakita, H. Visible-Light Photocatalysis with Phosphorus-Doped Titanium(IV) Oxide Particles Prepared Using a Phosphide Compound. Appl. Catal. B 2013, 132-133, 39-44. (32) Omar, F. S.; Numan, A.; Duraisamy, N.; Bashir, S.; Ramesh, K.; Ramesh, S. Ultrahigh Capacitance of Amorphous Nickel Phosphate for Asymmetric Supercapacitor Applications. RSC Adv. 2016, 6, 76298-76306. (33) Militzer, C.; Buchsbaum, J.; Dzhagan, V.; Zahn, D. R. T.; Wulff, H.; Helm, C. A.; Goedel,W. Atomic Layer Deposition of Titanium Phosphate from Titanium Tetrachloride and Triethyl Phosphate onto Carbon Fibers. Adv. Mater. Interfaces 2018, 5, 1800423. (34) Li, Z.; Wei, L.; Jiang, W.; Hu, Z.; Luo, H.; Zhao, W.; Xu, T.; Wu, W.; Wu, M.; Hu, J. Chemical State of Surrounding Iron Species Affects the Activity of Fe-Nx for Electrocatalytic Oxygen Reduction. Appl. Catal. B 2019, 251, 240-246. (35) Tien, H.-W.; Huang, Y.-L.; Yang, S.-Y.; Wang, J.-Y.; Ma, C. The Production of Graphene Nanosheets Decorated with Silver Nanoparticles for Use in Transparent, Conductive Films. Carbon 2011, 49, 1550-1560. (36) Zou, G.; Hou, H.; Foster, C. W.; Banks, C. E.; Guo, T.; Jiang, Y.; Zhang, Y.; Ji, X. Advanced Hierarchical Vesicular Carbon Co-Doped with S, P, N for High-Rate Sodium Storage. Adv. Sci. 2018, 5,1800241. (37) Jin, Z.-Q.; Liu, Y.-G.; Wang, W.-K.; Wang, A.-B.; Hu, B.-W.; Shen, M.; Gao, T.; Zhao, P.-C.; Yang, Y. A New Insight into the Lithium Storage Mechanism of Sulfurized Polyacrylonitrile with no Soluble Intermediates. Energy Storage Mater. 2018, 14, 272-278. (38) Song, Y.; Bai, S.; Zhu, L.; Zhao, M.; Han, D.; Jiang, S.; Zhou, Y. Tuning Pseudocapacitance via C-S Bonding in WS2 Nanorods Anchored on N,S Codoped Graphene for High-Power Lithium Batteries. ACS Appl. Mater. Interfaces 2018, 10, 13606-13613. (39) Han, J.; Hirata, A.; Du, J.; Ito, Y.; Fujita, T.; Kohara, S.; Ina, T.; Chen, M. Intercalation Pseudocapacitance of Amorphous Titanium Dioxide@Nanoporous Graphene for High-Rate and Large-Capacity Energy Storage. Nano Energy 2018, 49, 354-362. (40) Lv, C.; Yan, C.; Chen, G.; Ding, Y.; Sun, J.; Zhou, Y.; Yu, G. An Amorphous Noble-Metal-Free Electrocatalyst that Enables Nitrogen Fixation under Ambient Conditions. Angew. Chem. Int. Ed. 2018, 57, 6073-6076. (41) Gao, J.; Jiang, B.; Ni, C.; Qi, Y.; Zhang, Y.; Oturan, N.; Oturan, M. A. Non-Precious Co3O4-TiO2/Ti Cathode Based Electrocatalytic Nitrate Reduction: Preparation, Performance and Mechanism. Appl. Catal. B 2019, 254, 391-402. (42) Yige Yan. TiO2 Photocatalysts Prepared via a Sol-Gel Route Assisted by P- and F- Containing Additives : Applications to the Degradation of MEK and to the Elimination of Bacteria on Surfaces. Other. Université de Strasbourg, 2016. English.pp86-90, ⟨NNT: 2016STRAF063⟩. (43) Zhao, C.; Cai, Y.; Yin, K.; Li, H.; Shen, D.; Qin, N.; Lu, Z.; Liu, C.; Wang, H. Carbon-Bonded, Oxygen-Deficient TiO2 Nanotubes with Hybridized Phases for Superior Na-Ion Storage. Chem. Eur. J. 2018, 350, 201-208. (44) Deng, S.; Zhang, Y.; Xie, D.; Yang, L.; Wang, G.; Zheng, X.; Zhu, J.; Wang, X.; Yu, Y.; Pan, G.; Xia, X.; Tu, J. Oxygen Vacancy Modulated Ti2Nb10O29-x Embedded onto Porous Bacterial Cellulose Carbon for Highly Efficient Lithium Ion Storage. Nano Energy 2019, 58, 355-364. 28


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(45) Zeng, Y.; Lai, Z.; Han, Y.; Zhang, H.; Xie, S.; Lu, X. Oxygen-Vacancy and Surface Modulation of Ultrathin Nickel Cobaltite Nanosheets as a High-Energy Cathode for Advanced Zn-Ion Batteries. Adv. Mater. 2018, 30,1802396. (46) Yang, J.; Zhou, X.; Wu, D.; Zhao, X.; Zhou, Z. S-Doped N-Rich Carbon Nanosheets with Expanded Interlayer Distance as Anode Materials for Sodium-Ion Batteries. Adv. Mater. 2017, 29 ,1604108. (47) Auer, A.; Steiner, D.; Portenkirchner, E.; Kunze-Liebhäuser, J. Nonequilibrium Phase Transitions in Amorphous and Anatase TiO2 Nanotubes. ACS Appl. Energy Mater. 2018, 1, 1924-1929. (48) Auer, A.; Portenkirchner, E.; Gotsch, T.; Valero-Vidal, C.; Penner, S. Kunze-Liebhauser, J. Preferentially Oriented TiO2 Nanotubes as Anode Material for Li-Ion Batteries: Insight into Li-Ion Storage and Lithiation Kinetics. ACS Appl. Mater. Interfaces 2017, 9, 36828-36836. (49) Acevedo-Peña, P.; Haro, M.; Rincón, M. E.; Bisquert, J.; Garcia-Belmonte, G. Facile Kinetics of Li-ion Intake Causes Superior Rate Capability in Multiwalled Carbon Nanotube@TiO2 Nanocomposite Battery Anodes. J. Power Sources 2014, 268, 397-403. (50) Ha, J. U.; Lee, J.; Abbas, M. A.; Lee, M. D.; Lee, J.; Bang, J. Designing Hierarchical Assembly of Carbon-Coated TiO2 Nanocrystals and Unraveling the Role of TiO2/Carbon Interface in Lithium-Ion Storage in TiO2. ACS Appl. Mater. Interfaces 2019, 11, 11391-11402. (51) Ji, L.; Gu, M.; Shao, Y.; Li, X.; Engelhard, M. H.; Arey, B. W.; Wang, W.; Nie, Z.; Xiao, J.; Wang, C.; Zhang, J. G.; Liu, J. Controlling SEI Formation on SnSb-Porous Carbon Nanofibers for Improved Na ion Storage. Adv. Mater. 2014, 26, 2901-2908. (52) Qian, J.; Chen, Y.; Wu, L.; Cao, Y.; Ai, X.; Yang, H. High Capacity Na-Storage and Superior Cyclability of Nanocomposite Sb/C Anode for Na-Ion Batteries. Chem. Commun. 2012, 48 , 7070-7072. (53) Li, Y.; Wang, D.; An, Q.; Ren, B.; Rong, Y.; Yao, Y. Flexible Electrode for Long-Life Rechargeable Sodium-ion Batteries: Effect of Oxygen Vacancy in MoO3−x. J. Mater. Chem. A 2016, 4, 5402-5405. (54) Chen, J.; Yang, B.; Hou, H.; Li, H.; Liu, L.; Zhang, L.; Yan, X. Disordered, Large Interlayer Spacing, and Oxygen‐Rich Carbon Nanosheets for Potassium Ion Hybrid Capacitor. Adv. Energy Mater. 2019, 9, 1803894. (55) Li, H.; Lang, J.; Lei, S.; Chen, J.; Wang, K.; Liu, L.; Zhang, T.; Liu, W.; Yan, X. A High-Performance Sodium-Ion Hybrid Capacitor Constructed by Metal-Organic Framework-Derived Anode and Cathode Materials. Adv. Funct. Mater. 2018, 1800757. (56) Li, P.; Hwang, J.-Y.; Park, S.-M.; Sun, Y. Superior Lithium/Potassium Storage Capability of Nitrogen-Rich Porous Carbon Nanosheets Derived from Petroleum Coke. J. Mater. Chem. A 2018, 6, 12551-12558. (57) Fang, G.; Wu, Z.; Zhou, J.; Zhu, C.; Cao, X.; Lin, T.; Chen, Y.; Wang, C.; Pan, A.; Liang, S. Observation of Pseudocapacitive Effect and Fast Ion Diffusion in Bimetallic Sulfides as an Advanced Sodium-Ion Battery Anode. Adv. Energy Mater.2018, 8, 1703155. (58) Su, D.; Dou, S.; Wang, G. Anatase TiO2: Better Anode Material Than Amorphous and Rutile Phases of TiO2 for Na-Ion Batteries. Chem. Mater. 2015, 27, 6022-6029. 29


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(59) He, H.; Sun, D.; Zhang, Q.; Fu, F.; Tang, Y.; Guo, J.; Shao, M.; Wang, H. Iron-Doped Cauliflower-Like Rutile TiO2 with Superior Sodium Storage Properties. ACS Appl. Mater. Interfaces 2017, 9, 6093-6103. (60) Marcano, C.; Kosynkin, V.; Berlin, M.; Sinitskii, A.; Sun, Z.; Slesarev, A. Improved Synthesis of Graphene Oxide. ACS Nano 2010, 4, 4806–4814. (61) Kresse, G.; Furthmüller, J. Efficiency of Ab Initio Total Energy Calculations for Metals and Semiconductors Using a Plane-Wave Basis Set. Comp. Mater. Sci. 1996, 6, 15-50. (62) Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized Gradient Approximation Made Simple. Phys. Rev. Lett. 1996, 77, 3865-3868. (63) Kresse, G.; Joubert, D. From Ultrasoft Pseudopotentials to the Projector Augmented-Wave Method. Phys.Rev. B 1999, 59, 1758-1775. (64) Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A Consistent and Accurate Ab Initio Parametrization of Density Functional Dispersion Correction (DFT-D) for the 94 Elements H-Pu. J. Chem. Phys. 2010, 132, 154104.

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Controllably Enriched Oxygen Vacancies through Polymer Assistance

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