Bridging Covalently Functionalized Black Phosphorus on Graphene

Subscriber access provided by LAURENTIAN UNIV

Article

Bridging Covalently Functionalized Black Phosphorus on Graphene for High Performance Sodium-ion Battery Hanwen Liu, Li Tao, Yiqiong Zhang, Chao Xie, Peng Zhou, Hongbo Liu, Ru Chen, and Shuangyin Wang ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.7b11599 • Publication Date (Web): 05 Oct 2017 Downloaded from http://pubs.acs.org on October 7, 2017

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

ACS Applied Materials & Interfaces is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 25

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

ACS Applied Materials & Interfaces

Bridging Covalently Functionalized Black Phosphorus on Graphene for High Performance Sodium-ion Battery Hanwen Liu,† Li Tao,† Yiqiong Zhang,† Chao Xie,† Peng Zhou,† Hongbo Liu,*† Ru Chen,*† Shuangyin Wang*†‡ †

State Key laboratory of Chem/Bio-sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.

‡

Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, Shenzhen University, 518060, China.

*

Corresponding

author

E-mail:

[email protected];

[email protected];

[email protected].

Abstract: Black phosphorus (BP) has recently arisen researchers’ great interest as promising anode materials for sodium-ion battery (SIB), owing to its high theoretical capacity (2596 mAh g-1) and good electric conductivity (about 300 S m-1). However, the large volume variation during electrochemical cycling makes it difficult for practical application. Herein, the reversible performance of BP in SIB is significantly enhanced by bridging covalently functionalized BP on graphene. The enhanced interaction between the chemical functionalized BP and graphene improves the stability of BP during long-cycle running of SIB. The bridging reduces the surface energy and increases thickness of BP available for enlarging the channel between BP nanosheet and graphene. The enlarged channel stores more sodium ions for improving cycle performance. Significantly, two types of phosphorus-carbon bond are firstly detected during experimental analysis. Benefiting from the strategy, the BPbased SIB anode exhibits 1472 mAh g-1 specific capacity at 0.1A g-1 in the 50th cycle and 650 mAh g-1 at 1 A g-1 after 200th cycles. Keywords: black phosphorus, graphene, chemical bonding, anode, sodium ion battery

1. Introduction With the gradual development of commercial lithium-ion battery (LIB), researchers are paying more attention to sodium-ion battery (SIB) which is an attractive candidate to 1 ACS Paragon Plus Environment


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

substitute for lithium counterpart. There are noticeable advantages on sodium: wide distribution, high abundance and low cost as well as environmental-friendly compatibility, which are not available for lithium. However, if the SIB were used in daily lives, it should be safe and stable with satisfying capacity. To achieve the purpose, researchers have successfully synthesized new types of cathode of SIB, such as NaMnO2, NaFePO4 and Na3V2(PO4)3.1-5 These sodium compounds can effectively prevent the occurrence of dendrites forming, which often occurs if using sodium as cathode directly thus causing battery to short-circuit and even firing. So the cardinal challenge for SIB inheres in exploring new types of anode material with high reversible capacity. Some researchers attempt to use commercial LIB anode material such as graphite to be the SIB counterpart but failed. Because the ion channel between graphene layers is just 0.186 nm, not large enough for sodium ion (0.204 nm) insertion/extraction. The radius of sodium ion is 55% larger than that of lithium ion, which is a reason why many LIB anode materials exhibiting poor capacity in SIB.6 Therefore, it is necessary to investigate a new sort of materials for SIB anode with satisfactory capacity. Researches on lead compound (Na15Pb4, theoretical capacity: 485 mAh g-1)7 and tin compound (Na15Sn4, theoretical capacity: 847 mAh g-1)8-10 have suggested these metals as promising candidate for SIB anode but their theoretical capacities are below 1000 mAh g-1. Some anodes such as alloy-type anode materials,11-14 carbonaceous materials,15-17 metal oxides as well as sulfides anode materials18-23 do not have enough capacities, while other anode material with high theoretical capacity such as silicon24 is electrochemically inactive for SIB. It sounds plausible that phosphorus (2596 mAh g-1) is one of the best candidates for SIB anode. Phosphorus exists in three main allotropes: white P, red P and black P. White phosphorus consists of tetrahedral P4 molecules which is highly reactive in air and toxic for human body. Therefore, it is unsuitable for SIB anode. Red phosphorus which is more stable than white phosphorus, has been researched as an anode material for LIB and SIB.25-37 But its poor electrical conductivity (about 10-14 S cm-1) and large volume change (over 400%) during 2 ACS Paragon Plus Environment

Page 2 of 25

Page 3 of 25

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


discharged/charged cycle limit further development.38-40 Black phosphorus (BP), the most thermodynamically stable allotrope,41,42 with good electrical conductivity (about 300 S m-1) is a two-dimension crystal material whose channel size is 0.308 nm, big enough for storing sodium. However, the huge volume change during insertion/extraction of sodium leads to the pulverization of BP and then disperse in electrolyte, no longer sticking to current collector and out of work. This issue results in rapid capacity fading. Therefore, it is necessary to take some measures to relieve the volume change to increase the cycle performance of BP. Previous works on combining P with carbon-based materials have been proven as an effective way to relieve the volume expansion during electrochemical cycle. Some carbonbased materials such as graphene layers have large specific surface area, encapsulate the BP slice layer by layer thus keeping it in shape during insertion/extraction process.43 Others such as carbonized metal-organic frameworks with highly porous structure stabilize P particles in the porous structure and relieve the strain from volume variation.44 Moreover, high-energy ball milling is another popular strategy to combine phosphorus with carbon.6 Typically, the carbon material such as carbon nanotube with excellent conductivity is evenly mixed with phosphorus particles by milling at high temperature and pressure, enhancing the tolerance of the large volume change during cycling. By this mean, carbon nanotube is chemically bonded with phosphorus which facilitating stability and electric conductivity. In addition to the above strategies, downsizing the bulk or particle of phosphorus to nanosize is an alternative method. For example, Sun et al.45 stripes bulky BP into two-dimensional phosphorene by ultrasonication and centrifugal separation. The as-obtained phosphorene combined with graphene at crystal scale makes overcoming volume expansion possible. But the productivity of phosphorene is very low and unsuitable for industrial production. Herein, we present a rational synthesis of 4-nitrobenzene-diazonium (4-NBD) modified BP chemically bonding with reduced graphene oxide (RGO) hybrid (4-RBP) to improve the SIB 3 ACS Paragon Plus Environment


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

anode performance of BP. Typically, having 4-NBD modified, the BP nanosheet links to nitrobenzene by P-C bond (type 1) on the surface, which increases the thickness of BP nanosheet. The modified BP nanosheet is solvothermally reacted with graphene oxide (GO) and layers of RGO is coated on the BP connected by P-C bond (type 2) and P-O-C bond. The channel between RGO and BP becomes larger due to the 4-NBD modification and stores more sodium ions. The unique two-dimensional structure possesses various advantages: (1) the facile synthesis of BP nanosheet just requires ultrasonic stripping without centrifugal separation, which guarantees adequate output in each preparation; (2) the unique twodimensional structure sandwiches BP nanosheet in layers of RGO slice, not only relieving the strain from volume change but also enhancing the electron conduction; (3) the channels between RGO and modified BP layers provide a short diffusion distance for sodium ions. Benefiting from the above advantages, the 4-RBP hybrid displays attracting cycle performance in SIB anode. Typically, it shows a high reversible capacity of 1472 mAh g-1 at current density of 0.1 A g-1 in the 50th cycle and 650 mAh g-1 at current density of 1A g-1 in the 200th cycle. Considered the facile synthesis and outstanding cycle performance, the 4-RBP hybrid is promising for practical application in approaching SIB. Based on the above design, we summarize the following four strategies for improving the cycling performance of BP: (1) reduced graphene oxide (RGO) which was chosen to encapsulate BP works as an elastic buffer to accommodate the volume expansion during sodium insertion/extraction process; (2) the RGO slice is stably connected to BP by chemical bonds which maintain excellent electrical connection during reversible cycle; (3) the bulky BP striped into nanosheet disperses evenly in the channel of layers of RGO; (4) surface modification of BP nanosheet enlarges the channel between BP and RGO for storing more sodium ions and improving cycle performance. 2. Results and Discussion 4 ACS Paragon Plus Environment

Page 4 of 25

Page 5 of 25

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


2.1. Synthesis and Characterization According to the Raman spectra (Figure 1a), the as-obtained 4-NBD@BP (4-BP) and 4NBD@RGO@BP (4-RBP) materials show three Raman peaks appearing at 358 cm-1, 437 cm1

and 465 cm-1, corresponding to A1 g, B2g and A2 g modes of BP.46 The Raman spectra of

untreated BP is shown in Figure S1. In the meantime, two strong peaks located in 1331 and 1594 cm-1 which are assigned to D and G band respectively. Comparing with RGO, the two bands of 4-RBP move forward, which might be attributed to the chemical bonds between RGO and BP. The intensity of D band is stronger than that of G band, indicating there are a number of functional groups and defects on RGO.47 It is worth noting that, having 4-NBD modified, a small peak appears around 830 cm-1 and another one arises in 650cm-1 after solvothermal reacting with GO, both of which are corresponding to P-C bonds.48 Although they are all P-C bonds, their Raman shifts emerge in different position because the phosphorus atoms are connected with different types of carbon atoms (nitrobenzene and RGO). Powder X-ray diffraction (XRD) spectra are shown in Figure 1b. A strong diffraction peak at 2θ = 24.3° is consistent with the (002) plane of hexagonal crystalline graphite (JCPDS 411487), indicating the GO has been solvothermally reduced.6 The crystalline domain size of the RGO above is around 15 nm, which implying several layers of graphene according to the Scherrer equation.6 Besides, another six diffraction peaks at 2θ of 16.6°, 27.3°, 34.4°, 35.1°, 52.3° and 56.3° are consistent with (020), (021), (040), (111), (060) and (132) planes of orthorhombic black phosphorus (JCPDS 73-1358), which indicating that the orthorhombic structure of BP keeps stable after solvothermal reaction in 140 °C. When comparing 4-RBP with RBP, the 2θ of each crystallographic planes have no change indicating the interplanar spacing won’t alter after 4-NBD modification. To find out the impact of 4-NBD modification, the atomic force microscope (AFM) is performed. The measured thickness of BP flake is ranged from 4.1 to 5.8nm (Figure 1e), 5 ACS Paragon Plus Environment


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

equivalent to five to seven phosphorene layers for the thickness of a layer of phosphorene is about 0.84nm.45 Having 4-NBD modified, the thickness of BP flake increases by approximately 1.1nm (Figure 1f). The increasing thickness provides wider channel between BP interface and RGO slice for storing more sodium ions (Figure 1g). To further investigate the type of P-C bonds between BP and nitrobenzene, BP and RGO, the samples are characterized by FT-IR. According to Figure 2a, the P-C bond (type 1) between BP and nitrobenzene appears in around 1500cm-1. Formation of the bond is driven by interaction between BP and Aryl diazonium, which is agree well with the former work.48 The P-C bond (type 2) in Figure 2b is detected around 1420 cm-1, which indicates linking BP to RGO. As 4-NBD modified BP is solvothermally bonding with RGO, the P-C bond shifts between 1420 and 1500 cm-1 indicates coexistence of the two types of bonds. According to former papers6, P-C bonds will remarkably contribute to the stability of black phosphorus during lithiated/delithiated process. To study the intensity of P-C bonds, X-ray photoelectron spectroscopy (XPS) was conducted (Figure 3). In Figure 3a and 3c, the C-O and C=O bonds were detected, which are originated from GO signifying the GO was not entirely reduced when undergoing 140 °C solvothermal process. Both of the bonds do increase structural disorder and reduce the energy barrier to chemical reaction49, contributing to the formation of P-C bonds. The P-C bonds showed in Figure 3a at ~284 eV is evidently weaker than the counterpart in Figure 3c, implying the enhancement of P-C bonds after 4-NBD modification. When comparing Figure 3b with 3d, it is obvious that the P-C bonds in the Figure 3d are extremely outstanding while the P-O-C bonds50-54 keep in the same level of intensity, implying the P-C bonds from 4-RBP between BP and RGO are as many as the equivalent from RBP. Based on the above analysis, 4-NBD modification does positively impact on BP that increasing the number of P-C bonds to maintain the stability of BP. Besides, both the P-C and P-O-C bonds have the power to bond BP to nitrobenzene/RGO, keeping BP in steady state during the lithiated/delithiated process 6 ACS Paragon Plus Environment

Page 6 of 25

Page 7 of 25

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


thus improving reversible cycle. In spite of the chemical bonds, the peaks at ~129.8 and ~130.7 eV corresponding to the symbol of BP structure. It is noteworthy that having 4-NBD modified, the characteristic peaks of BP shift forward, which is relevant to the surface modification of BP. The structure of 4-RBP was further characterized by transmission electron microscope (TEM) as shown in Figure 4. The BP flake is completely coated by multilayer RGO thus constructing a shell structure, which is further proved by the EDS elemental mapping (Figure S3-S5). It is obvious that there are many wrinkles coating on the BP flake, resulting from layers of graphene during solvothermal reduction of GO. When coated by multilayer RGO, the BP nanosheet will keep in good shape during the process of sodium insertion/extraction. The single-crystalline of BP flake is confirmed by SAED pattern as shown in the inset of Figure 4a, which corresponding to (020) interplanar spacing of orthorhombic BP. Observed closely, the BP nanosheet (Figure 4b) in the core of shell emerged different shades of color resulting from a variety of thickness. This result agrees well with the AFM in Figure 1. To further study the combination of 4-NBD modified BP and RGO, the HRTEM image (Figure 4c) is taken from area 1 in Figure 4b. As seen, the single-crystal structure of orthorhombic BP is closely surrounded by amorphous structure of multilayer RGO, indicating RGO is not simply physically coated on BP. The edge between single-crystal structure and amorphous structure is the location of P-C/P-O-C bonds. Layers of RGO are caught inside the black box of Figure 4c distinguished by shades of colour. Moreover, the crystal lattice of BP is very neat and its interplanar spacing is 0.52nm, which is equivalent to (020) lattice plane. Interestingly, the edge dislocations, a type of lattice distortion rarely observed, is detected in the white circle of Figure 4c, which is possibly caused by solvothermal treatment. In contrast to Figure 4c, the lattice of Figure 4d keeps in lighter colour indicating thinner thickness. As shown in black box in Figure 4d, two layers of BP show different thickness: the thinner one is more obscure located on top while the thicker counterpart in deeper is situated in below. As the thickness 7 ACS Paragon Plus Environment


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

turns thinner, we can see the crystal structure of BP is merged with amorphous RGO and PC/P-O-C bonds are the bridge linking the two materials. 2.2. Electrochemical Performance and Obeservation With the advanced structures, the materials were characterized for SIB. As shown in Figure 5a, there are three oxidation peaks in the first cathodic scan of cyclic voltammograms (CV). Peak I at 1 V disappears in the subsequent scan, which is probably due to the formation of the SEI film6 in the first cycle. As the potential is further scanned to 0.5 V, the appearance of peak II is equivalent to the process of embedding sodium ions to form NaP and Na2P. With the development of the sodium ions insertion, sodium ions are continuously oxidized to Na3P resulting in the appearance of peak III. The appearing of peak IV in 0.5 V indicating the extraction of sodium ions from the charged NaxP phase to NayP (1 ≤ y < x ≤ 3).55 Having gone through the process of V, most of the sodium ions are reduced to Na atoms except some of the sodium ions still combine with phosphorus thus causing irreversible changes in the structure. These changes have great impact on the following reversible cycles and transform the positions of redox peaks. The corresponding process on the different cycles are further shown in Figure 5b. In contrast to the second cycle, there is no much difference in the 10th cycle despite of specific capacity. This means the anode hybrid is totally activated during the first cycle and the specific capacity will be mostly reversible except for irreversible attenuation. The attenuation is caused by the degeneration of BP structure during long-time insertion/extraction of sodium ions. To slow down this degeneration, BP flake is modified by 4-NBD and bonding to nitrobenzene by P-C bonds, which will reduce surface energy and improve stability.48 Moreover, RGO is coated on the modified BP to keep it in shape during the course of contraction and expansion, and 4-NBD modification could also enlarge the channel between BP nanosheet and RGO flake for storing more sodium ions to improve cycle performance. By this ways, the 4-RBP anode keeps 1272 mAh g-1 specific capacity in the 50th cycle. On the 8 ACS Paragon Plus Environment

Page 8 of 25

Page 9 of 25

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


contrary, the pure BP anode delivers a bad reversible capacity(below 100 mAh g-1) because the BP flake is decomposed during the 1st charged process, which has been reported by the previous report.43 Besides, to better investigate the commercial potential of the 4-RBP anode, the electrochemical impedance spectroscopy (EIS) is conducted as shown in figure 5c. Compared to the pristine anode, the charge transfer resistance is much lower after 10 cycles, which attributed to the increasing of electrical contact after activation. As increase of the cycles, resistance in the 30th cycle is higher than the 10th, indicating the irreversible changes in structure of 4-RBP anode after long-time cycling. Without 4-NBD the resistance of RBP is lower than that of 4-RBP indicating the organic modification increases electrochemical impedance to some extent (Figure S10). As shown in Figure 5d, the 4-RBP anode delivers the first discharged specific capacity of 2500 mAh g-1 in 0.1A g-1, which is very close to the theoretical specific capacity of BP (2596 mAh g-1). Although it sharply plunges to 1700 mAh g-1 in the second round due to the formation of irreversible structure NazP (1 ≤ z ≤ 3) during the first cycle,45 a high capacity of 1472 mAh g-1 is still obtained after 50 cycles. The mass of BP is calculated by TGA in Figure S6. To analyze the function of 4-NBD modification, the RBP anode in ratio of 1:2 (BP:GO) is compared with 4-RBP. The RBP anode performs 850 mAh g-1 capacity in the 50th cycle. The capacity difference indicates that the increasing thickness of BP flake upon 4-NBD modification provides wider channel between BP interface and RGO slice for storing more sodium ions to raise reversible capacity. When altering the solvothermal ratio from 1:2 (modified BP:GO) to 1:1 and 1:3, the 4-RBP hybrid shows different specific capacity as depicted in Figure S7-S9. Without P-C bonds, the specific capacity is significantly plunging to below 100mAh g-1 in the 10th round (Figure S11). Figure 5e shows the cycle performance and coulombic efficiency of 4-RBP at 1A g-1 current density. The anode acquires 650 mAh g-1 reversible capacity in the 200th cycle, indicating the anode hybrid keeps good performance even at high rate. As shown in Figure 5f, the specific capacities of ~1400, ~890, ~740 and ~660 mAh g-1 are obtained at the current densities of 0.1, 9 ACS Paragon Plus Environment


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

0.3, 0.5 and 1 A g-1 respectively. Only 80 mAh g-1 specific capacity is fallen when the current density was raised from 0.5 to 1 A g-1. As the current density restored to 0.1 A g-1 after 50 cycles, the specific capacity returns to 1210 mAh g-1 indicating a well reversible performance, which is mainly owed to the stable structure between modified BP and RGO linked by P-C and P-O-C bonds. P-C and P-O-C bonds fix the modified BP to RGO thus constructing the major structure of 4-RBP. Meanwhile, BP flake modified by 4-NBD provides wider channel between BP interface and RGO slice for storing more sodium ions to raise reversible capacity. To analyze the composition of 4-RBP hybrid after electrochemical cycling, TEM was conducted as shown in Figure 6a. The main part of the hybrid is obviously swelled due to the irreversible product of Na3P during discharged/charged process. However, 4-BP is still coated with RGO indicating the stability of P-C and P-O-C bonds. There are a number of sodium inserted products dispersing in the hollow space of RGO gap which was empty before cycling (see Figure 4a), which indicates a huge volume expansion after sodium insertion. Benefited from hollow skeleton of RGO, the chalking of BP flake does not lose in electrolyte immediately. Instead, the 4-RBP anode keeps on working efficiently. On the edge of the hybrid, a small part of BP hybrid is already exposed to electrolyte causing irreversible attenuation. According to the SAED in Figure 6b, the polycrystalline NaxP (1 ≤ x ≤ 3) is detected by diffraction rings, which is in accord with the tagged NaxP in Figure 6a, indicating the irreversible change of the 4-RBP structure after the first discharge. This result agrees well with the CV profile in Figure 5a. 3. Conclusion We, for the first time, have synthesized 4-RBP material by a simple modification of BP and solvothermal react with GO to form a 4-NBD modified BP bonding with RGO for SIB anode. Inside the 4-RBP hybrid, the surface of BP nanosheet is modified by nitrobenzene connected by P-C bond (type 1), the modified BP nanosheet is encapsulated by RGO flakes which are reduced from GO and the connection between BP and RGO is P-C (type 2) and P-O-C bonds. 10 ACS Paragon Plus Environment

Page 10 of 25

Page 11 of 25

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


Two types of P-C bonds are unprecedentedly detected by Raman spectra and FT-IR spectra, and the difference of intensity is shown in XPS. The RGO flakes work as an elastic buffer to accommodate the volume expansion during sodium insertion/extraction process and enhance the electron conduction. Between the RGO slice and modified BP nanosheet, chemical bonds maintain excellent electrical connection during reversible cycle. Furthermore, the modified BP nanosheets enlarge the channel with RGO layers for storing more sodium ions and improving cycle performance. Benefiting from the above structural advantages, the 4-RBP anode exhibits a high reversible capacity of 1472 mAh g-1 at current density of 0.1 A g-1 in the 50th cycle and 650 mAh g-1 at current density of 1A g-1 in the 200th cycle. Considering the facile synthesis and outstanding reversible performance, the 4-RBP anode with modified BP chemically bonding to RGO possesses a great potential for further application in approaching SIB. 4. Experimental Section Preparation of BP: Bulk black phosphorus (BP) was prepared by a catalytic transport route in low pressure according to the literature.56 Typically, high pure red phosphorus (500 mg), SnI4 (20 mg) and Sn (10 mg) were sealed in an evacuated quartz tube. The tube was horizontally placed into the middle of muffle furnace and heated at 650 °C for 5 h with a heating rate of 80 °C per hour. Then the temperature was declined to 500 °C with a cooling rate of 20 °C per hour followed with a natural cooling process. The bulk BP was washed with hot toluene and acetone for several times. After dried in 50 °C vacuum oven, bulk BP (50 mg) was ground into powder and dispersed in NMP (50 ml) with sonication for further application. Preparation of GO: Graphene oxide (GO) was prepared by a modified Hummers.57 Generally, Flake graphite (2 g) and NaNO3 (1 g) were slowly added into concentrated H2SO4 (46 ml) with mechanical agitation. The mixture was stirred for 0.5 h below 10 °C followed with the addition of KMnO4 (6 g). After another 0.5 h reaction, the mixture was stirred at 35 °C for 1h and added DI water (95 ml) later. Finally, the mixture was stirred in 140 °C for 11 ACS Paragon Plus Environment


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

0.5 h and added H2O2 (15 ml) afterwards. The mixture was washed with DI water followed with the vacuum freeze-drying process. Preparation of 4-NBD modified BP (4-BP): The bulk of BP (30 mg) was dispersed in NMP (60 ml) and ultrasonically stripped for two days. 4-nitrobenzene-diazonium (4-NBD 142.2 mg) and tetrabutylammonium hexafluorophosphate (2.324 g) were added to the stripped BP dispersion keeping for 30min. The mixture was then filtered and washed by NMP for several times. Preparation of 4-RBP: The prepared 4-BP was dispersed in NMP (60 ml) and mixed with GO (60 mg). The mixture was poured into a solvothermal reactor in which KOH (60 mg) was added to protect the BP from oxidation.58 The reactor was heated in 140 °C for 6 h and naturally cooling to room temperature afterwards. The mixture was washed by ethanol and DI water. Preparation of RBP: BP (30 mg) mixed with GO (60 mg) and NMP (60 ml) was poured into a solvothermal reactor in which KOH (60 mg) was added. The reactor was heated in 140 °C for 6 h and naturally cooling to room temperature afterwards. The mixture was washed by ethanol and DI water. Physical characterizations: X-ray diffraction (XRD) was performed on Bruker D8 Advance diffractometer with Cu Kα radiation (λ = 1.54178 Å). Raman spectra was collected on a Raman spectrometer (Labram-010) using 532 nm laser at room temperature. Scanning electron microscopy (SEM) images and corresponding energy dispersive spectrometry(EDS) mapping were taken on JSM-6700F scanning electron microscope. Transmission electron microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM), selected area electron diffraction (SAED) and corresponding energy dispersive spectrometry (EDS) were performed on Tecnai G2 F20 with an acceleration voltage of 200 kV. X-ray photoelectron spectroscopic (XPS) measurements were carried out with an ESCALAB 250Xi using a monochromic Al X-ray source (200 W, 20 eV) and Fourier Transform infrared 12 ACS Paragon Plus Environment

Page 12 of 25

Page 13 of 25

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


spectroscopy (FT-IR) was tested by Tensor 27. The galvanostatic charge and discharge tests were carried on battery test instrument (LAND CT2001A). Electrochemical measurements: The 4-RBP electrode was prepared by spreading a mixture of 80 wt % active material, 10 wt % super P and 10 wt % carboxymethyl cellulose sodium salt (2 wt %) onto a copper foil current collector. The as-prepared electrode was then dried at 80 °C in a vacuum oven for 12 h. The loading density was controlled at about 1.5 mg cm−2. The electrochemical performance of the 4-RBP composite was characterized by assembling it as an anode in coin cells (type 2032) in an argon-filled glovebox. The electrode was separated from the sodium counter electrode by a separator (glass fiber). The electrolyte used in the cell was 1 M NaPF6 in propylene carbonate (PC) with 2 vol % uoroethylene carbonate (FEC) as additive. The galvanostatic charge and discharge tests were carried on battery test instrument (LAND CT2001A). Cyclic voltammogram (CV) at a scan rate of 0.1 mV s-1 and electrochemical impedance spectra (EIS) over the frequency range from 100 kHz to 0.01 Hz with the amplitude of 5 mV were conducted on a potentiostat galvanostat (Metrohm Autolab PGSTAT302N). The stress–strain test was carried on SEM tester 100. The TGA was performed on DTG-60. Supporting Information Raman spectra of untreated BP and XPS survey of 4-RBP; EDS elemental mapping and TGA of 4-RBP; specific capacity of 4-RBP based on different ratio of solvothermal BP: GO; EIS of 4-RBP and RBP; specific capacity of RBP and BP.

Conflicts of interest There are no conflicts of interest to declare. 13 ACS Paragon Plus Environment


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

Acknowledgements The authors acknowledge support from the National Natural Science Foundation of China (Grant No. 51402100 and 21573066), the Provincial Natural Science Foundation of Hunan (Grant no. 2016JJ1006 and 2016TP1009) and the Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province. Notes and references 1 Xiang, X.; Zhang, K.; Chen, J. Recent Advances and Prospects of Cathode Materials for Sodium-Ion Batteries. Adv. Mater. 2015, 27 (36), 5343-5364. 2 Jiang, Y.; Yang, Z.; Li, W.; Zeng, L.; Pan, F.; Wang, M.; Wei, X.; Hu, G.; Gu, L.; Yu, Y. Nanoconfined Carbon-Coated Na3V2(PO4)3 Particles in Mesoporous Carbon Enabling Ultralong Cycle Life for Sodium-Ion Batteries. Adv. Energy Mater. 2015, 5 (10), 1402104. 3 Zhu, C.; Kopold, P.; van Aken, P. A.; Maier, J.; Yu, Y. High Power-High Energy Sodium Battery Based on Threefold Interpenetrating Network. Adv. Mater. 2016, 28 (12), 2409-2416. 4 Zhang, Y. Q.; Ma, Z. L.; Liu, D. D.; Dou, S.; Ma, J. M.; Zhang, M.; Guo, Z. P.; Chen, R.; Wang, S. Y. p-Type SnO Thin Layers on n-Type SnS2 Nanosheets with Enriched Surface Defects and Embedded Charge Transfer for Lithium Ion Batteries. J. Mater. Chem. A 2017, 5 (2), 512-518. 5

Billaud, J.; Clément, R. J.; Armstrong, A. R.; Canales-Vázquez, J.; Rozier, P.; Grey, C. P.; Bruce, P. G. β-NaMnO2: A High-Performance Cathode for Sodium-Ion Batteries. J. Am. Chem. Soc. 2014, 136 (49), 17243-17248.

6 Song, J.; Yu, Z.; Gordin, M. L.; Hu, S.; Yi, R.; Tang, D.; Walter, T.; Regula, M.; Choi, D.; Li, X.; Manivannan, A.; Wang, D. Chemically Bonded Phosphorus/Graphene Hybrid as a High Performance Anode for Sodium-Ion Batteries. Nano Lett. 2014, 14 (11), 6329-6335. 7 Jow, T. R.; Shacklette, L. W.; Maxfield, M.; Vernick, D. The Role of Conductive Polymers in Alkali-Metal Secondary Electrodes. J. Electrochem. Soc. 1987, 134 (7), 1730-1733. 8 Zhu, H.; Jia, Z.; Chen, Y.; Weadock, N.; Wan, J.; Vaaland, O.; Han, X.; Li, T.; Hu, L. Tin Anode for Sodium-Ion Batteries Using Natural Wood Fiber as a Mechanical Buffer and Electrolyte Reservoir. Nano Lett. 2013, 13 (7), 3093-3100. 14 ACS Paragon Plus Environment

Page 14 of 25

Page 15 of 25

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


9 Wang, J. W.; Liu, X. H.; Mao, S. X.; Huang, J. Y. Microstructural Evolution of Tin Nanoparticles during In Situ Sodium Insertion and Extraction. Nano Lett. 2012, 12 (11), 5897-5902. 10 Liu, Y.; Xu, Y; Zhu, Y,; Culver, J. N.; Lundgren, C. A.; Xu, K.; Wang, C. Tin-Coated Viral Nanoforests as Sodium-Ion Battery Anodes. ACS Nano 2013, 7 (4), 3627-3634. 11 Zhu, Y.; Han, X.; Xu, Y.; Liu, Y.; Zheng, S.; Xu, K.; Hu, L.; Wang, C. Electrospun Sb/C Fibers for a Stable and Fast Sodium-Ion Battery Anode. ACS Nano 2013, 7 (7), 6378-6386. 12 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 (56), 7070-7072. 13 He, M.; Kravchyk, K.; Walter, M.; Kovalenko, M. V. Monodisperse Antimony Nanocrystals for High-Rate Li-ion and Na-ion Battery Anodes: Nano versus Bulk. Nano Lett. 2014, 14 (3), 1255-1262. 14 Liu, Y.; Zhang, N.; Jiao, L.; Chen, J. Tin Nanodots Encapsulated in Porous NitrogenDoped Carbon Nanofibers as a Free-Standing Anode for Advanced Sodium-Ion Batteries. Adv. Mater. 2015, 27 (42), 6702-6707. 15 Xu, J.; Wang, M.; Wickramaratne, N. P.; Jaroniec, M.; Dou, S.; Dai, L. HighPerformance Sodium Ion Batteries Based on a 3D Anode from Nitrogen-Doped Graphene Foams. Adv. Mater. 2015, 27 (12), 2042-2048. 16 Li, W.; Zeng, L.; Yang, Z.; Gu, L.; Wang, J.; Liu, X.; Cheng, J.; Yu, Y. FreeStanding and Binder-Free Sodium-Ion Electrodes with Ultralong Cycle Life and High Rate Performance Based on Porous Carbon Nanofibers. Nanoscale 2014, 6 (2), 693698. 17 Tang, K.; Fu, L.; White, R. J.; Yu, L.; Titirici, M. M.; Antonietti, M.; Maier, J. Hollow Carbon Nanospheres with Superior Rate Capability for Sodium-Based Batteries. Adv. Energy Mater. 2012, 2 (7), 873-877. 18 Liu, J.; Song, K.; Zhu, C.; Chen, C. C.; van Aken, P. A.; Maier, J.; Yu, Y. Ge/C Nanowires as High-Capacity and Long-Life Anode Materials for Li-Ion Batteries. ACS Nano 2014, 8 (7), 7051-7059. 19 David, L.; Bhandavat, R.; Singh, G. MoS2/Graphene Composite Paper for SodiumIon Battery Electrodes. ACS Nano 2014, 8 (2), 1759-1770. 20 Fan, X. Y.; Shi, X. Y.; Wang, J.; Shi, Y. X.; Wang, J. J.; Xu, L.; Gou, L.; Li, D. L. Sucrose Assisted Hydrothermal Synthesis of SnO2/Graphene Nanocomposites with 15 ACS Paragon Plus Environment


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

Improved Lithium Storage Properties. J. Solid State Electrochem. 2013, 17 (1), 201208. 21 Wu, L.; Bresser, D.; Buchholz, D.; Giffin, G. A.; Castro, C. R.; Ochel, A.; Passerini, S. Unfolding the Mechanism of Sodium Insertion in Anatase TiO2 Nanoparticles. Adv. Energy Mater. 2015, 5 (2), 1401142. 22 Wu, Y.; Liu, X.; Yang, Z.; Gu, L.; Yu, Y. Nitrogen-Doped Ordered Mesoporous Anatase TiO2 Nanofibers as Anode Materials for High Performance Sodium-Ion Batteries. Small 2016, 12 (26), 3522-3529. 23 Wu, C.; Jiang, Y.; Kopold, P.; van Aken, P. A.; Maier, J.; Yu, Y. Peapod-Like Carbon-Encapsulated Cobalt Chalcogenide Nanowires as Cycle-Stable and High-Rate Materials for Sodium-Ion Anodes. Adv. Mater. 2016, 28 (33), 7276-7283. 24 Chevrier, V. L.; Ceder, G. Challenges for Na-Ion Negative Electrodes. J. Electrochem. Soc. 2011, 158 (9), 1011-1014. 25 Qian, J.; Qiao, D.; Ai, X.; Cao, Y.; Yang, H. Reversible 3-Li Storage Reactions of Amorphous Phosphorus as High Capacity and Cycling-Stable Anodes for Li-Ion Batteries. Chem. Commun. 2012, 48 (71), 8931-8933. 26 Wang, L.; He, X.; Li, J.; Sun, W.; Gao, J.; Guo, J.; Jiang, C. Nano-Structured Phosphorus Composite as High-Capacity Anode Materials for Lithium Batteries. Angew. Chem. Int. Ed. 2012, 51 (36), 9034-9037. 27 Marino, C.; Debenedetti, A.; Fraisse, B.; Favier, F.; Monconduit, L. ActivatedPhosphorus as New Electrode Material for Li-Ion Batteries. Electrochem. Commun. 2011, 13 (4), 346-349. 28 Li, W. J.; Chou, S. L.; Wang, J. Z.; Liu, H. K.; Dou, S. X. Simply Mixed Commercial Red Phosphorus and Carbon Nanotube Composite with Exceptionally Reversible Sodium-Ion Storage. Nano Lett. 2013, 13 (11), 5480-5484. 29 Qian, J.; Wu, X.; Cao, Y.; Ai, X.; Yang, H. High Capacity and Rate Capability of Amorphous Phosphorus for Sodium Ion Batteries. Angew. Chem. Int. Ed. 2013, 125 (17), 4731-4734. 30 Kim, Y.; Park, Y.; Choi, A.; Choi, N. S.; Kim, J.; Lee, J.; Ryu, J. H.; Oh, S. M.; Lee, K. T. An Amorphous Red Phosphorus/Carbon Composite as a Promising Anode Material for Sodium Ion Batteries. Adv. Mater. 2013, 25 (22), 3045-3049. 31 Yabuuchi, N.; Matsuura, Y.; Ishikawa, T.; Kuze, S.; Son, J. Y.; Cui, Y. T.; Oji, H.; Komaba, S. Phosphorus Electrodes in Sodium Cells: Small Volume Expansion by

16 ACS Paragon Plus Environment

Page 16 of 25

Page 17 of 25

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


Sodiation

and

the

Surface-Stabilization

Mechanism

in

Aprotic

Solvent.

ChemElectroChem 2014, 1 (3), 580-589. 32 Ren, X.; Zhou, J.; Qi, X.; Liu, Y.; Huang, Z.; Li, Z.; Ge, Y.; Dhanabalan, S. C.; Ponraj, J. S.; Wang, S.; Zhong, J.; Zhang, H. Few-Layer Black Phosphorus Nanosheets as Electrocatalysts for Highly Efficient Oxygen Evolution Reaction. Adv. Energy Mater. 2017, DOI: 10.1002/aenm.201700396. 33 Chen, L.; Zhou, G.; Liu, Z.; Ma, X.; Chen, J.; Zhang, Z.; Ma, X.; Li, F.; Cheng, H. M.; Ren, W. Scalable Clean Exfoliation of High-Quality Few-Layer Black Phosphorus for a Flexible Lithium Ion Battery. Adv. Mater. 2016, 28 (3), 510-517. 34 Ren, X.; Li, Z.; Huang, Z.; Sang, D.; Qiao, H.; Qi, X.; Li, J.; Zhong, J.; Zhang, H. Environmentally Robust Black Phosphorus Nanosheets in Solution: Application for Self-Powered Photodetector. Adv. Funct. Mater. 2017, 27 (18), 1606834. 35 Liu, H.; Zou, Y.; Tao, L.; Ma, Z.; Liu, D.; Zhou, P.; Liu, H.; Wang, S. Sandwiched Thin-Film Anode of Chemically Bonded Black Phosphorus/Graphene Hybrid for Lithium-Ion Battery. Small 2017, DOI: 10.1002/smll.201700758. 36 Liu, Y.; Zhang, A.; Shen, C.; Liu, Q.; Cao, X.; Ma, Y.; Chen, L.; Lau, C.; Chen, T. C.; Wei, F.; Zhou, C. Red Phosphorus Nanodots on Reduced Graphene Oxide as a Flexible and Ultra-Fast Anode for Sodium-Ion Batteries. ACS Nano 2017, 11 (6), 5530-5537. 37 Xu, G. L.; Chen, Z.; Zhong, G. M.; Liu, Y.; Yang, Y.; Ma, T.; Ren, Y.; Zuo, X.; Wu, X.

H.;

Zhang,

X.;

Amine,

K.

Nanostructured

Black

Phosphorus/

Ketjenblack−Multiwalled Carbon Nanotubes Composite as High Performance Anode Material for Sodium-Ion Batteries. Nano Lett. 2016, 16 (6), 3955-3965. 38 Sun, J.; Zheng, G.; Lee, H. W.; Liu, N.; Wang, H.; Yao, H.; Yang, W.; Cui, Y. Formation of Stable Phosphorus-Carbon Bond for Enhanced Performance in Black Phosphorus Nanoparticle-Graphite Composite Battery Anodes. Nano Lett. 2014, 14 (8), 4573-4580. 39 Jiang, Q. Q.; Xu, L.; Chen, N.; Zhang, H.; Dai, L. M.; Wang, S. Y. Facile Synthesis of Black Phosphorus: an Efficient Electrocatalyst for the Oxygen Evolving Reaction. Angew. Chem. Int. Ed. 2016, 128 (44), 14053-14057. 40 Komaba, S.; Ishikawa, T.; Yabuuchi, N.; Murata, W.; Ito, A.; Ohsawa, Y. Fluorinated Ethylene Carbonate as Electrolyte Additive for Rechargeable Na Batteries. ACS Appl. Mater. Interfaces 2011, 3 (11), 4165-4168. 41 Morita, A. Semiconducting Black Phosphorus. Appl. Phys. A 1986, 39 (4), 227-242. 17 ACS Paragon Plus Environment


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

Page 18 of 25

42 Hultgren, R.; Gingrich, N. S.; Warren, B. E. The Atomic Distribution in Red and Black Phosphorus and the Crystal Structure of Black Phosphorus. J. Chem. Phys. 1935, 3 (6), 351-355. 43 Xia, W.; Zhang, Q.; Xu, F.; Ma, H.; Chen, J.; Qasim, K.; Ge, B.; Zhu, C.; Sun, L. Visualizing

the

Electrochemical

Lithiation/Delithiation

Behaviors

of

Black

Phosphorus by In Situ Transmission Electron Microscopy. J. Phys. Chem. C 2016, 120 (11), 5861-5868. 44 Li, W.; Hu, S.; Luo, X.; Li, Z.; Sun, X.; Li, M.; Liu, F.; Yu, Y. Confined Amorphous Red Phosphorus in MOF-Derived N-Doped Microporous Carbon as a Superior Anode for Sodium-Ion Battery. Adv. Mater. 2017, 29 (16), 1605820. 45 Sun, J.; Lee, H. W.; Pasta, M.; Yuan, H.; Zheng, G.; Sun, Y.; Li, Y.; Cui, Y. A Phosphorene-Graphene Hybrid Material as a High-Capacity Anode for Sodium-Ion Batteries. Nature Nanotech. 2015, 10 (11), 980-985. 46 Wang, H.; Yang, X.; Shao, W.; Chen, S.; Xie, J.; Zhang, X.; Wang, J.; Xie, Y. Ultrathin Black Phosphorus Nanosheets for Efficient Singlet Oxygen Generation. J. Am. Chem. Soc. 2015, 137 (35), 11376-11382. 47 Malard, L. M.; Pimenta, M. A.; Dresselhaus, G.; Dresselhaus, M. S. Raman Spectroscopy in Grapheme. J. Phys. Rep. 2009, 473 (5), 51-87. 48 Ryder, C. R.; Wood, J. D.; Wells, S. A.; Yang, Y.; Jariwala, D.; Marks, T. J.; Schatz, G. C.; Hersam, M. C. Covalent Functionalization and Passivation of Exfoliated Black Phosphorus via Aryl Diazonium Chemistry. Nature Chem. 2016, 8 (6), 597-602. 49 Dreyer, D. R.; Park, S.; Bielawski, C. W.; Ruoff, R. S. The Chemistry of Graphene Oxide. Chem. Soc. Rev. 2010, 39 (1), 228-240. 50 Pearce, S. R. J.; May, P. W.; Wild, R. K.; Hallam, K. R.; Heard, P. J. Deposition and Properties of Amorphous Carbon Phosphide Films. Diamond Relat. Mater. 2002, 11 (3), 1041-1046. 51 Fuge, G. M.; May, P. W.; Rosser, K. N.; Pearce, S. R. J.; Ashfold, M. N. R. Laser Raman and X-ray Photoelectron Spectroscopy of Phosphorus Containing DiamondLike Carbon Films Grown by Pulsed Laser Ablation Methods. Diamond Relat. Mater. 2004, 13 (4), 1442-1448. 52 Han, J. C.; Liu, A. P.; Zhu, J. Q.; Tan, M. L.; Wu, H. P. Effect of Phosphorus Content on Structural Properties of Phosphorus Incorporated Tetrahedral Amorphous Carbon Films. Appl. Phys. A 2007, 88 (2), 341-345.


Page 19 of 25

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


53 Some, S.; Kim, J.; Lee, K.; Kulkarni, A.; Yoon, Y.; Lee, S.; Kim, T.; Lee, H. Highly Air-Stable Phosphorus-doped n-Type Graphene Field-Effect Transistors. Adv. Mater. 2012, 24 (40), 5481-5486. 54 Zhang, C.; Mahmood, N.; Yin, H.; Liu, F.; Hou, Y. Synthesis of Phosphorus-doped Graphene and Its Multifunctional Applications for Oxygen Reduction Reaction and Lithium Ion Batteries. Adv. Mater. 2013, 25 (35), 4932-4937. 55 Park, C. M.; Sohn, H. J. Black Phosphorus and Its Composite for Lithium Rechargeable Batteries. Adv. Mater. 2007, 19 (18), 2465-2468. 56 Köpf, M.; Eckstein, N.; Pfister, D.; Grotz, C.; Krügera, I.; Greiwea, M.; Hansenb, T.; Kohlmannc, H.; Nilges, T. Access and In Situ Growth of Phosphorene-Precursor Black Phosphorus. J. Cryst. Growth 2014, 405 (1), 6-10. 57 Hummers Jr, W. S.; Offeman, R. E. Preparation of Graphitic Oxide. J. Am. Chem. Soc. 1958, 80 (6), 1339. 58 Xu, Y.; Wang, Z.; Guo, Z.; Huang, H.; Xiao, Q.; Zhang, H.; Yu, X. F. Solvothermal Synthesis and Ultrafast Photonics of Black Phosphorus Quantum Dots. Adv. Optical Mater. 2016, 4 (8), 1223-1229.



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

Figure caption Fig. 1. a: Raman spectra of 4-NBD modified BP (4-BP) and 4-NBD modified BP bonding with RGO (4-RBP). b: XRD patterns of BP bonding with RGO (RBP) and 4-RBP. c-f: AFM of BP flake and 4-BP. g: Molecular model of 4-NBD modification and bonding with RGO. Fig. 2. a: FT-IR spectra of 4-NBD, BP and 4-NBD modified BP (4-BP). b: FT-IR spectra of BP with RGO (RBP) and 4-NBD modified BP with RGO (4-RBP). Fig. 3. a,b: High resolution C 1s and P 2p XPS spectra of BP bonding with RGO (RBP). c,d: High resolution C 1s and P 2p XPS spectra of 4-NBD modified BP bonding with RGO (4RBP). Fig. 4. a: A typical TEM image of 4-NBD modified BP bonding with RGO (4-RBP) and the corresponding SAED image. b: The amplified TEM image of a. c: The HRTEM of Area 1 in b. d: The HRTEM of Area 2 in b. Fig. 5. a: The cyclic voltammograms of the 4-NBD modified BP bonding with RGO (4-RBP) anode at a the scanning rate of 0.1 mV/s. b: Typical discharged/charged voltage profiles of the 4-RBP anode in different cycle numbers. c: The electrochemical impedance spectroscopy (EIS) of the 4-RBP. d: Specific capability of the 4-RBP and the RBP anode at current density of 0.1 A/g. e: Specific capability and coulombic efficiency of the 4-RBP anode at current density of 1 A/g. f: The specific capacity of 4-RBP at different current density. The specific capacities above are based on the mass of the BP. Fig. 6. a: A typical TEM image of 4-NBD modified BP bonding with RGO (4-RBP) after the 10th electrochemical cycles. b: The corresponding SAED image of a.


Page 20 of 25

Page 21 of 25

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


Fig. 1. a: Raman spectra of 4-NBD modified BP (4-BP) and 4-NBD modified BP bonding with RGO (4-RBP). b: XRD patterns of BP bonding with RGO (RBP) and 4-RBP. c-f: AFM of BP flake and 4-BP. g: Molecular model of 4-NBD modification and bonding with RGO.

Fig. 2. a: FT-IR spectra of 4-NBD, BP and 4-NBD modified BP (4-BP). b: FT-IR spectra of BP with RGO (RBP) and 4-NBD modified BP with RGO (4-RBP).



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

Fig. 3. a,b: High resolution C 1s and P 2p XPS spectra of BP bonding with RGO (RBP). c,d: High resolution C 1s and P 2p XPS spectra of 4-NBD modified BP bonding with RGO (4RBP).


Page 22 of 25

Page 23 of 25

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


Fig. 4. a: A typical TEM image of 4-NBD modified BP bonding with RGO (4-RBP) and the corresponding SAED image. b: The amplified TEM image of a. c: The HRTEM of Area 1 in b. d: The HRTEM of Area 2 in b.

Fig. 5. a: The cyclic voltammograms of the 4-NBD modified BP bonding with RGO (4-RBP) anode at a the scanning rate of 0.1 mV/s. b: Typical discharged/charged voltage profiles of the 4-RBP anode in different cycle numbers. c: The electrochemical impedance spectroscopy (EIS) of the 4-RBP. d: Specific capability of the 4-RBP and the RBP anode at current density of 0.1 A/g. e: Specific capability and coulombic efficiency of the 4-RBP anode at current density of 1 A/g. f: The specific capacity of 4-RBP at different current density. The specific capacities above are based on the mass of the BP. 23 ACS Paragon Plus Environment


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

Fig. 6. a: A typical TEM image of 4-NBD modified BP bonding with RGO (4-RBP) after the 10th electrochemical cycles. b: The corresponding SAED image of a.


Page 24 of 25

Page 25 of 25

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


24x12mm (300 x 300 DPI)

ACS Paragon Plus Environment

Bridging Covalently Functionalized Black Phosphorus on Graphene

Recommend Documents