Research Article Cite This: ACS Appl. Mater. Interfaces XXXX, XXX, XXX-XXX
www.acsami.org
Controllable Self-Assembly of Micro-Nanostructured Si-Embedded Graphite/Graphene Composite Anode for High-Performance Li-Ion Batteries Ning Lin,* Tianjun Xu, Tieqiang Li, Ying Han, and Yitai Qian* Department of Chemistry, University of Science and Technology of China, Hefei, Anhui Province 230026, P. R. China S Supporting Information *
ABSTRACT: Si-containing graphite-based composites are considered as promising high-capacity anodes for lithium-ion batteries (LIBs). Here, a controllable and scalable self-assembly strategy is developed to produce micronanostructured graphite/Si/reduced graphene oxides composite (SGG). The selfassembly procedure is realized by the hydrogen bond interaction between acylamino-modified graphite and graphene oxides (GO); Si nanoparticles are in situ embedded between graphite and GO sheets uniformly. This architecture is able to overcome the incompatibility between Si nanoparticles and microsized graphite. Accordingly, the as-prepared SGG anode (Si 8 wt %) delivers a reversible Li-storage capacity of 572 mAh g−1 at 0.2 C, 502.2 mAh g−1 after 600 cycles at 0.8 C with a retention of 92%, and a capacity retention of 64% even at 10 C. The impressive electrochemical properties are ascribed to the stable architecture and three-dimensional conductive network constructed by graphite and graphene sheets, which can accommodate the huge volume change of Si, keep the conductive contact and structural integrity, and suppress side reactions with electrolyte. Additionally, the full-cell (LiFePO4 cathode/SGG anode) delivers a specific capacity of 550 mAh g−1 with a working potential beyond 3.0 V. KEYWORDS: Si, graphite, graphene, self-assembly, Li-ion batteries
■
INTRODUCTION Li-ion batteries (LIBs) have been widely used for portable consumer electronics and in the electric vehicles market.1,2 The electrode materials are known to be predominant in determining energy density and cycling life-span of LIBs. Graphitized carbon materials have been used as anodes for decades because of the highly stable structure and long life cycling properties.3 However, the commercial graphite products are approaching their theoretical capacity limit (372 mAh g−1), which cannot satisfy the increasing energy demand.4 Silicon (Si)-based materials were demonstrated as promising anode candidates for LIBs because of their high theoretical specific capacity (3572 mAh g−1) and low working voltage (300%) during discharge/ charge cycling, resulting in formation of unstable and thicker solid electrolyte interface films and thus rapid capacity decay upon cycling.7,8 Various strategies have been developed to address those issues. Design of nanostructured Si anodes such as nanoparticles, nanotubes, and nanowires was demonstrated as an effective approach because the nanosized Si could release the strain−stress induced by volume change and retain the structural integrity.9−11 For example, Cui prepared Si nanowires that exhibit a reversible specific capacity of 3500 mAh g−1 after 20 cycles at 840 mA g−1.9 The other well-accepted approach is © XXXX American Chemical Society
coating a carbonaceous layer such as amorphous carbon or graphene sheets on the Si.12−17 For example, Si/graphene, prepared by polymer assisted self-assembly process, showed a specific capacity of 1205 mA h g−1 after 150 cycles at 100 mA g−1. However, the nanostructured materials are difficult to employ for practical applications due to the high specific surface area and corresponding high surface energy.18 Alternatively, the mixture of microsized graphite with nano-Si to produce micro-nanostructured Si/graphite composite has been considered as a potential practical anode for high-energy LIBs. The binary composite can make full use of the stable mechanical structure of graphite and the high specific capacity of Si component. The key issues that need to be addressed for fabricating the Si/graphite composite are the incompatibility and inhomogeneous distribution between the microsized graphite and nanosized Si.19 To date, various fabricating routes have been developed for producing Si/graphite-based composite, including mechanical ball-milling mixture, liquid-phase spray-drying, and chemical vapor deposition (CVD). Note that carbonaceous additives were generally used as “glue” to overcome the incompatibility between the nano-Si and micrographite, thus constructing a Received: July 20, 2017 Accepted: October 23, 2017 Published: October 23, 2017 A
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
Research Article
ACS Applied Materials & Interfaces
Figure 1. (a) Illustration of the fabricating procedure of SGG composite. (b) Digital pictures of the polyacrylamide (PAM) modified graphite, ballmilled Si particles, and graphene oxides suspension. (c) Hydrogel-like product after self-assembling reaction. (d) Final SGG composite after annealing treatment.
content facilitates the high reversible capacity and (2) stable architecture composed of both graphite and graphene is beneficial for accommodating the volume change and enhancing the conductivity, thus maintaining the electrode integrity and forming stable solid electrolyte interphase (SEI) film.
stable structure. For example, Cui prepared graphite/Si/ amorphous carbon composite (Si: 6 wt %) through chemical vapor deposition of nano-Si and amorphous carbon in turn on the graphite surface, delivering a specific capacity of 476.6 mAh g−1 over 100 cycles at about 0.25 A g−1.17 Su prepared Si/ carbon/graphite microspheres (Si: 5 wt %) by a spray-drying and annealing process, delivering specific capacity of 435 mAh g−1 at 500 mA g−1 and 380 mAh g−1 at 1000 mA g−1.20 Kim prepared Si/amorphous carbon/graphite (Si: 20 wt %) composite through ball-milling of Si, pitch, and graphite sheet precursors followed by annealing treatment, and a reversible Listorage specific capacity of 448 mAh g−1 was obtained after 30 cycles at 140 mA g−1.21 Despite great development made in this field, there are still some challenges, such as the unstable and loose structure of the blended composite, graphite demolition problem caused by mechanical milling methods, and requirement of expensive and highly toxic precursors for the CVD methods. In this work, a controllable and scalable self-assembly strategy is developed for fabricating graphite/Si/reduced graphene oxide composite (SGG), as shown in Figure 1a. The self-assembly reaction is initiated by the hydrogen bond interaction of functional group (carboxyl and hydroxyl)-rich graphene oxides (GO) sheets and the micrographite modified by acylamino-containing polyacrylamide (PAM). During this process, Si nanoparticles, well-distributed in the suspension, are uniformly embedded into the voids between graphite and GO sheets. After annealing treatment, micro-nanostructured SGG composite is obtained, forming a stable architecture and conductive network. As a result, the SGG (Si 8 wt %) composite anode shows good Li-storage properties, including a specific capacity of 572 mAh g−1 at 0.2 C and 502.2 mAh g−1 at 0.8 C after 600 cycles, and excellent rate capability with a capacity retention of 64% even at current density of 10 C. In contrast, the Si/graphite (SG) composite, prepared by direct ball-milling, shows a rapid capacity fading to 432 mAh g−1 after 100 cycles at 0.2 C. The impressive electrochemical performance of SGG is attributed to the following aspects: (1) Si
■
EXPERIMENTAL SECTION
■
RESULTS AND DISCUSSION
The Si nanoparticles were prepared through mechanical ball-milling treatment; details are in the Supporting Information. GO powder was made according to a modified Hummer’s method.22 The preparation of SGG composite was realized by self-assembly and annealing treatment process, as shown in Figure 1a. First, modification of graphite is conducted through ball-milling the obtained graphite and polyacrylamide (PAM) (weight ratio of 2/1) with deionized water solvent in a zirconia vial to form a homogeneous suspension (denoted as suspension A). Then, the ball-milled Si powder was distributed in deionized water by ultrasonication and mixed with the GO suspension (denoted as suspension B). Figure 1b shows the digital pictures of the Si, GO, and PAM-modified graphite suspension. The ζ-potential of PAM-modified graphite is −12.7 mV at 25 °C. Therefore, it is reasonable to speculate that the PAM−graphite suspension is relatively stable. Second, the suspension B was poured into the suspension A rapidly to initiate the self-assembly reaction (Figure 1c). Third, the hydrogel-like product was collected and heattreated at 900 °C under Ar atmosphere for 2 h. The weight ratio of graphite to Si was 9/1. As a contrast, the Si/graphite composite (weight ratio of 1/9) was prepared by direct mixture of Si particles and graphite flakes, denoted as SG. The Materials Characterization and Electrochemical Measurements sections are detailed in the Supporting Information. Note that the current densities of 1 C of graphite, Si, SGG anode, and SG are set as 370, 3600, 600, and 700 mA g−1, respectively.
Figure 1a illustrates the schematic procedure for producing SGG composite anode. Note that the Si nanoparticles and graphite flake components were prepared by ball-milling the bulk precursors. First, the graphite flake surfaces were decorated by acylamino-rich PAM, which was realized by B
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
Research Article
ACS Applied Materials & Interfaces
Figure 2. (a) X-ray diffraction patterns and (b) Raman spectra of as-prepared Si nanoparticles, microsized graphite, SG blend, and SGG composite.
Figure 3. SEM pictures of the (a) Si, (b) graphite, (c) SG, and (d, e) SGG. (f) TEM picture of the SGG sample.
originated from carbon components are also detected. The SGG composite shows ID/IG higher than that of commercial graphite (0.84 vs 0.62), indicating more defects in the SGG composite (Figure S1). The relative band intensity of Si in the SG composite is higher than that in the SGG composite because the Si nanoparticles are dispersed on the surface of graphite flakes and naked without the coating layer in the SG composite, while the Si nanoparticles are all covered by graphene sheets in the SGG composite. Figure 3a presents the SEM image of the ball-milled Si particles, showing irregular nanostructure. The particle size of the nano-Si ranges from 120 to 380 nm with an average size about 190 nm, as exhibited in Figure S2. The ball-milled flakelike graphite shows a smooth surface with the particle size below 20 μm (Figure 3b). Figure 3c exhibits the SEM picture of the SG blend, revealing its loose and incompact structure composed of nano-Si and micrographite. It is noteworthy that the Si nanoparticles in this composite are strongly agglomerated because of the high surface energy. Figures 3d−f present the SEM and TEM images of the SGG composite. The surface of SGG becomes rough due to the encapsulation of graphene sheets, and the overall particle size is close to that of the graphite flakes. The enlarged SEM and TEM pictures reveal that the Si nanoparticles are uniformly embedded between the well-connected graphite flakes and graphene sheets, and no
mechanical ball-milling treatment. Then, the PAM-modified graphite suspension was mixed with the nano-Si and GOcontaining suspension, and the self-assembly reaction was initiated by the hydrogen bond interaction between the acylamino groups on the graphite surface and the carboxyl (or hydroxyl) on the GO sheets.23 In this process, the welldistributed nano-Si were in situ embedded between the graphite flakes and the GO sheets. After annealing treatment, the SGG composite was obtained. Figures 1b−d exhibit the digital pictures of the different samples. The modified graphite can be suspended well in the distilled water due to the help of hydrophilic groups in the PAM (Figure 1b). After initiating selfassembly reaction, a ball of black floccule hydrogel was formed in the bottom, and the suspension became transparent (Figure 1c). It is noteworthy that the as-prepared hydrogel-like product can be easily collected for annealing treatment (Figure 1d). Figure 2a exhibits the XRD patterns of the as-synthesized products. The sharp and intensive diffraction peaks of the nanosized Si and microsized graphite powders indicate their well-crystallized nature. As for the SGG and SG composite, the diffraction patterns contain a group of sharp peaks of graphite and the main diffraction peak of crystalline Si at 28.5°. Figure 2b shows the Raman spectra of SGG, SG, graphite, and Si. The characterization bands of Si component are located at 510 and 920 cm−1. The D-band (1360 cm−1) and G-band (1580 cm−1) C
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
Research Article
ACS Applied Materials & Interfaces
Figure 4. (a) TGA plots and (b) N2 adsorption−desorption isotherms of the graphite, Si, and SGG samples; the inserted picture is the BJH pore-size distributions of the SGG sample.
Figure 5. Li-ion storage performance of the obtained samples. (a) Discharge/charge voltage profiles, and (b) charge capacity at 0.2 C of the obtained graphite, SG, and SGG samples, and the Coulombic efficiency of SGG anode. (c) Specific capacity−voltage profiles and (d) cycling behavior with increasing current density from 0.5 to 10 C. (e) Reversible capacity and Coulombic efficiency measured at 0.8 C.
polymer. The weight change between 540 and 1000 °C is attributed to the burning of graphite and oxidation of Si. Therefore, the weight ratio of Si in the SGG composite is calculated to be about 8% (100 − 16 − 56 − 20%). Figure 4b exhibits the nitrogen adsorption and desorption isothermal of the Si, graphite, and SGG samples at 77 K, accompanied by the pore diameter distribution plot of the SGG composite. The calculated BET specific surface area of the Si, graphite, and SGG are 67.8, 7.5, and 18.6 m2 g−1, respectively. Noted that the BET specific surface area of the SG is 13 m2 g−1 (Figure S3). The relatively higher surface area of SGG composite compared to that of the graphite and SG composite is caused by the
naked Si particles are detected. Above all, it is concluded that the well-distributed micro-nanostructured SGG composite is produced through the proposed self-assembly strategy. Figure 4a exhibits the TGA plots of the Si, graphite, and SGG composite, measured under air atmosphere with the temperature ranging from 30 to 1000 °C. As the temperature increased, the Si particles were oxidized as SiO2, associated with a weight increase of 20% at 1000 °C. The graphite flakes begin to burn at 550 °C and can be burned out at 1000 °C; the residual ash is about 0.1%. As for the SGG samples, the weight loss of 16% between 400 and 540 °C is ascribed to the burning of RGO sheets and a little of amorphous carbon derived from D
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
Research Article
ACS Applied Materials & Interfaces
Figure 6. SEM pictures of the electrode surface change after 20 cycles of (a) graphite, (b) Si, (c) SG, and (d) SGG samples.
of Si-based electrode fades rapidly to 150 mAh g−1 at 0.2 C after only 50 cycles, as shown in Figure S6. To disclose the rate performance, the SGG electrode was investigated with increasing current density, as exhibited in Figures 5c and d. The reversible capacities of 558, 540, 520, 514, 502, 467, 434, and 390 mAh g−1 are obtained at 0.5, 1.0, 1.5, 2.0, 3.0, 5.0, 7.0, and 10 C, respectively. The capacity retention is maintained at 64% even at 10 C. After high-rate cycling, a reversible capacity as high as 550 mAh g−1 is recovered at 0.2 C. Figure 5d shows the corresponding potential−capacity profiles of SGG electrode at different current densities. Clearly, both the graphite and Si components contribute to the overall capacity at high current density, suggesting stable structure and good conductive connection. The high-rate cycling properties of SGG were measured at 0.8 C, as exhibited in Figure 5e. To activate the electrode sufficiently, a low current density of 0.2 C was adopted during the initial 3 cycles. The SGG anode delivers a reversible capacity of 502.2 mAh g−1 even over 600 cycles at 0.8 C, associated with a capacity retention of 92%, and the corresponding Coulombic efficiency is above 99.7%, indicating superior cycling stability. To better understand the volume change and the structural stability, AC impedance analysis and ex situ SEM were performed. Figure S7 shows the SEM images of as-prepared Si, graphite, SG, and SGG electrode surfaces before cycling. It can be seen that the active materials, binder, and carbon black are mixed uniformly. In the SG-based electrode, Si particles are naked without any protection. Figure 6 exhibits the SEM images of the electrode surfaces after 20 discharge/charge cycles. As for the graphite and SGG-based electrodes, the surface maintains smooth and flat due to formation of stable SEI membrane (Figures 6a and d). As a contrast, the Si-based
existence of nanostructured Si and graphene sheets. The pore size of the SGG composite is distributed widely from 5 to 150 nm. The generation of pores within the composite is originated from the void space between graphite and graphene sheets. The Li-ion storage properties of these as-prepared products were evaluated using coin-type half-cells. Figure 5a exhibits the capacity−voltage profiles at 0.2 C of the SGG, SG, and graphite-based electrodes during the first cycle. The lithiation potential plateaus of both graphite and Si components are below 0.2 V. The delithiation potential plateau of graphite is also located below 0.2 V. The charge potential plateau at 0.45 V is ascribed to the delithiation of LixSi alloys. The discharge/ charge potential plateaus of both graphite and Si are clearly observed in the SG and SGG samples, which are also determined by the CV measurements (Figure S4). In the first cycle, the discharge/charge capacities are 426/351 mA h g−1 for graphite, 887/678 mA h g−1 for SG, 810/572 mA h g−1 for SGG, and 3969/2868 mA h g−1 for Si particles (Figure S5), and their initial Coulombic efficiencies (ICE) are 83.4, 76.4, 71, and 72%, respectively. Note that the relatively low ICE of the SGG anode is generally caused by the defects in RGO sheets (or amorphous carbon), which would lead to the irreversible loss of Li ions upon cycling. The cycling properties of the as-prepared products were first evaluated at 0.2 C, as exhibited in Figure 5b. After 100 cycles, the graphite, SG, and SGG delivered the reversible capacity of 338, 432, and 542 mA h g−1, associated with the corresponding retention of 96, 62, and 95%, respectively. Obviously, the cycling stability of SGG anode is better than that of SG due to the stable structure. The Coulombic efficiency of the SGG anode is gradually increased from 71 to 99%, implying the formation of stable SEI films. In contrast, the reversible capacity E
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
Research Article
ACS Applied Materials & Interfaces
Figure 7. (a) Experimental (scatter diagram) and fitted (solid lines) Nyquist plots of (a) Si, (b) graphite, (c) SG, and (d) SGG-based electrodes before and after 20 cycles.
Figure 8. (a) Capacity−potential profiles and (b) cycling performance at 0.2 C of the full cell composed of a SGG anode and a LiFePO4 cathode.
electrode shows drastic surface change after cycling such as the generation of serious cracks and apparent electrode pulverization with a rough surface (Figure 6b), which is caused by the repeated volume variation and the generation of thick SEI film.24 Some obvious bumps are formed on the SG electrode surface (Figure 6c), which is resulted from the drastic volume change of naked Si component. After 100 cycles, the Si electrode is broken (Figure S8b). Large bumps are formed on the surface of the SG electrode, which also originate from the volume expansion of Si (Figure S8c). On the other hand, the graphite and SGG electrode surface can still maintain flatness (Figures S8a and d). Thus, it is confirmed that the as-prepared SGG composite with robust graphene sheets and mechanically stable graphite flakes could effectively buffer the volume variation of inner Si nanoparticles, forming a stable SEI layer. Figures 7a−d exhibit the experimental and fitted Nyquist curves of as-prepared nano-Si, micrographite, SG, and SGGbased electrodes with different discharge/charge cycles. Note that these two depressed semicircles are attributed to the resistance of the SEI membrane (Rsei) and the interphase contact resistance (Rint). A sloping line corresponds to the impedance of ionic diffusion in the solid active materials.25
Figure S9 shows the corresponding equivalent circuit. Table S1 shows the simulation results of the kinetic parameters. Before cycling, the SGG-based electrode shows the lowest interphase resistance (62.2 Ohm) due to the addition of conductive graphene sheets. After 20 cycles, the resistance of the graphite electrode is still low. However, the RSEI and Rint of the Si-based electrode increased remarkably to 73.01 and 197.3 Ohm because Si suffers from huge volume change, resulting in the formation of thick SEI film and bad conductive contact.26,27 The Rint of the SG electrode increased to 180.1 Ohm after 20 cycles, which is far larger than those of SGG and graphite electrodes. Therefore, it is speculated that the volume change of Si would destroy the electrode structural integrity; the graphite and graphene components are beneficial for forming stabilized SEI membrane, and the graphene sheets facilitate the improvement of the conductivity. To evaluate the possibility for practical application in LIBs, a coin-type full cell with an SGG anode and a commercially available LiFePO4 cathode was assembled and tested. The reversible capacity of the LiFePO4 cathode is 130 mAh g−1 at 1 C (1 C = 140 mA g−1) with a potential plateau at around 3.4 V in the half-cell, as exhibited in Figures S10a and b. The F
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
Research Article
ACS Applied Materials & Interfaces Notes
reversible specific capacity of the full cell was limited by the anode, which was assembled with anode/cathode capacity ratio of ca. 1:1.1. To compensate the initial Li-ion loss, the SGG anode was prelithiated in a half-cell prior to capacity matching with the cathode.14,28 Figure 8a shows the charge−discharge capacity−voltage plots with a potential window ranging from 2.0 to 3.8 V. As one can see, the main discharge voltage plateau ranges from 3.4 to 3.0 V, which suggests a stepwise lithiation procedure of graphite and Si components. The corresponding redox reaction of the full cell is formulated as the following equation: LiFePO4 + SGG = Li1−xFePO4 + LixSGG. The cycling behavior at 0.2 C is exhibited in Figure 8b. The full cell shows a first discharge capacity of 550 mAh g−1, associated with an ICE of 91%. After 50 cycles, the reversible capacity retention is 60%. From a practical point of view, it is necessary to optimize the assembling technique to obtain high performance full cells in the future work. The impressive electrochemical performance of the SGG composite, including long cycling stability and superior rate performance, are attributed to these following facts in terms of the stable and well-distributed micro-nanostructured structure and the conductive network. The Si nanoparticles are wellembedded between graphite and graphene sheets with a stable architecture, which could accommodate the volume change and maintain structural integrity. The graphite and graphene layers serve as protective and conductive layers which facilitate the improvement of ionic/electronic conductivity, suppressing side reactions with electrolyte. The derived void space in the composite shortens the ion transfer path, enhancing the rate performance.
The authors declare no competing financial interest.
■
ACKNOWLEDGMENTS We are thankful for financial support from the National Postdoctoral Program for Innovative Talents (Grant BX201600140), China Postdoctoral Science Foundation funded project (Grant 2016M600484), the Fundamental Research Funds for the Central Universities (Grant WK2060190078), and the National Natural Science Fund of China (Grant 21701163).
■
(1) Goodenough, J. B.; Kim, Y. Challenges for Rechargeable Li Batteries. Chem. Mater. 2010, 22, 587−603. (2) Luo, F.; Liu, B.; Zheng, J.; Chu, G.; Zhong, K.; Li, H.; Huang, X.; Chen, L. Nano-Silicon/Carbon Composite Anode Materials Towards Practical Application for Next Generation Li-Ion Batteries. J. Electrochem. Soc. 2015, 162, A2509−A2528. (3) Chen, M.; Wang, Z.; Wang, A.; Li, W.; Liu, X.; Fu, L.; Huang, W. Novel Self-Assembled Natural Graphite Based Composite Anodes with Improved Kinetic Properties in Lithium-ion Batteries. J. Mater. Chem. A 2016, 4, 9865−9872. (4) Yu, J.; Zhan, H.; Wang, Y.; Zhang, Z.; Chen, H.; Li, H.; Zhong, Z.; Su, F. Graphite Microspheres Decorated with Si Particles Derived from Waste Solid of Organosilane Industry as High Capacity Anodes for Li-ion batteries. J. Power Sources 2013, 228, 112−119. (5) Lin, N.; Han, Y.; Wang, L.; Zhou, J.; Zhou, J.; Zhu, Y.; Qian, Y. Preparation of Nanocrystalline Silicon from SiCl4 at 200° C in Molten Salt for High-Performance Anodes for Lithium Ion Batteries. Angew. Chem., Int. Ed. 2015, 54, 3822−3825. (6) Lin, N.; Han, Y.; Zhou, J.; Zhang, K.; Xu, T.; Zhu, Y.; Qian, Y. A Low Temperature Molten Salt Process for Aluminothermic Reduction of Silicon oOxides to Crystalline Si for Li-ion Batteries. Energy Environ. Sci. 2015, 8 (11), 3187−3191. (7) Zong, L.; Jin, Y.; Liu, C.; Zhu, B.; Hu, X.; Lu, Z.; Zhu, J. Precise Perforation and Scalable Production of Si Particles from Low-Grade Sources for High-Performance Lithium Ion Battery Anodes. Nano Lett. 2016, 16, 7210−7215. (8) Kim, H.; Seo, M.; Park, M. H.; Cho, J. A Critical Size of Silicon Nano-Anodes for Lithium Rechargeable Batteries. Angew. Chem., Int. Ed. 2010, 49, 2146−2149. (9) Chan, C. K.; Peng, H.; Liu, G.; McIlwrath, K.; Zhang, X. F.; Huggins, R. A.; Cui, Y. High-Performance Lithium Battery Anodes Using Silicon Nanowires. Nat. Nanotechnol. 2008, 3, 31−35. (10) Gauthier, M.; Mazouzi, D.; Reyter, D.; Lestriez, B.; Moreau, P.; Guyomard, D.; Roué, L. A Low-Cost and High Performance BallMilled Si-Based Negative Electrode for High-Energy Li-ion Batteries. Energy Environ. Sci. 2013, 6, 2145−2155. (11) Wen, Z.; Lu, G.; Mao, S.; Kim, H.; Cui, S.; Yu, K.; Huang, X.; Hurley, P. T.; Mao, O.; Chen, J. Silicon Nanotube Anode for LithiumIon Batteries. Electrochem. Commun. 2013, 29, 67−70. (12) Zhou, X.; Yin, Y. X.; Wan, L. J.; Guo, Y. G. Self-Assembled Nanocomposite of Silicon Nanoparticles Encapsulated in Graphene through Electrostatic Attraction for Lithium-Ion Batteries. Adv. Energy Mater. 2012, 2, 1086−1090. (13) Zhang, L.; Rajagopalan, R.; Guo, H.; Hu, X.; Dou, S.; Liu, H. A Green and Facile Way to Prepare Granadilla-Like Silicon-Based Anode Materials for Li-Ion Batteries. Adv. Funct. Mater. 2016, 26, 440−446. (14) Chen, S.; Shen, L.; van Aken, P. A.; Maier, J.; Yu, Y. DualFunctionalized Double Carbon Shells Coated Silicon Nanoparticles for High Performance Lithium-Ion Batteries. Adv. Mater. 2017, 29, 1605650. (15) Park, H.; Choi, S.; Lee, S.-J.; Cho, Y.-G.; Hwang, G.; Song, H.K.; Choi, N.-S.; Park, S. Design of an Altra-Durable Silicon-Based Battery Anode Material with Exceptional High-Temperature Cycling Stability. Nano Energy 2016, 26, 192−199.
■
CONCLUSION In summary, a controllable and scalable self-assembly strategy is developed for fabricating the SGG composite. The selfassembly reaction is realized by the hydrogen bond interaction of groups on the graphene oxide sheets and the polymermodified graphite. During this process, Si nanoparticles are embedded and uniformly distributed between graphite flakes and graphene sheets, forming a stable architecture and conductive network. The unique structure can buffer the repeated volume expansion of Si, suppress the side reactions, and enhance the conductivity. As an anode for LIBs, the SGG (Si: 8 wt %) anode shows improved reversible specific capacity, long lifespan, and superior rate capability. In addition, the fading mechanism and the full cell performance were also studied. The proposed strategy is also applicable for producing other high-capacity electrode materials for LIBs.
■
ASSOCIATED CONTENT
S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsami.7b10639. Experimental section, CV curves, SEM images, potential profiles, cycling properties, equivalent circuit, and nitrogen adsorption−desorption isotherms (PDF)
■
REFERENCES
AUTHOR INFORMATION
Corresponding Authors
*E-mail:
[email protected]. *E-mail:
[email protected]. ORCID
Ning Lin: 0000-0002-8029-5595 G
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
Research Article
ACS Applied Materials & Interfaces (16) Han, X.; Chen, H.; Li, X.; Wang, J.; Li, C.; Chen, S.; Yang, Y. Interfacial Nitrogen Stabilizes Carbon-Coated Mesoporous Silicon Particle Anodes. J. Mater. Chem. A 2016, 4, 434−442. (17) Han, X.; Chen, H.; Zhang, Z.; Huang, D.; Xu, J.; Li, C.; Chen, S.; Yang, Y. Carbon-Coated Si Micrometer Particles Binding to Reduced Graphene Oxide for a Stable High-Capacity Lithium-ion Battery Anode. J. Mater. Chem. A 2016, 4, 17757−17763. (18) Terranova, M. L.; Orlanducci, S.; Tamburri, E.; Guglielmotti, V.; Rossi, M. Si/C Hybrid Nanostructures for Li-ion Anodes: An Overview. J. Power Sources 2014, 246, 167−177. (19) Ko, M.; Chae, S.; Ma, J.; Kim, N.; Lee, H.-W.; Cui, Y.; Cho, J. Scalable Synthesis of Silicon-Nanolayer-Embedded Graphite for HighEnergy Llithium-Ion Batteries. Nature Energy 2016, 1, 16113. (20) Zhang, L.; Wang, Y.; Kan, G.; Zhang, Z.; Wang, C.; Zhong, Z.; Su, F. Scalable Synthesis of Porous Silicon/Carbon Microspheres as Improved Anode Materials for Li-Ion Batteries. RSC Adv. 2014, 4, 43114−43120. (21) Jo, Y. N.; Kim, Y.; Kim, J. S.; Song, J. H.; Kim, K. J.; Kwag, C. Y.; Lee, D. J.; Park, C. W.; Kim, Y. J. Si−Graphite Composites as Anode Materials for Lithium Secondary Batteries. J. Power Sources 2010, 195, 6031−6036. (22) Park, S.; An, J.; Piner, R. D.; Jung, I.; Yang, D.; Velamakanni, A.; Nguyen, S. T.; Ruoff, R. S. Aqueous Suspension and Characterization of Chemically Modified Graphene Sheets. Chem. Mater. 2008, 20, 6592−6594. (23) Lin, N.; Zhou, J.; Zhu, Y.; Qian, Y. Embedding Silicon Nanoparticles in Graphene Based 3D Framework by Cross-Linking Reaction for High Performance Lithium Ion Batteries. J. Mater. Chem. A 2014, 2, 19604−19608. (24) Chae, S.; Kim, N.; Ma, J.; Cho, J.; Ko, M. One-to-One Comparison of Graphite-Blended Negative Electrodes Using Silicon Nanolayer-Embedded Graphite versus Commercial Benchmarking Materials for High-Energy Lithium-Ion Batteries. Adv. Energy Mater. 2017, 7, 1700071. (25) Nie, P.; Liu, X.; Fu, R.; Wu, Y. T.; Jiang, J. M.; Dou, H.; Zhang, X. G. Mesoporous Silicon Anodes by Using Polybenzimidazole Derived Pyrrolic N-Enriched Carbon toward High-Energy Li-Ion Batteries. ACS Energy Lett. 2017, 2, 1279−1287. (26) Niu, J.; Zhang, S.; Niu, Y.; Song, H.; Chen, X.; Zhou, J.; Cao, B. Direct Amination of Si Nanoparticles for the Preparation of Si@ Uultrathin SiOx@graphene Nanosheets as High Performance LithiumIon Battery Anodes. J. Mater. Chem. A 2015, 3, 19892−19900. (27) Guo, J.; Sun, A.; Chen, X.; Wang, C.; Manivannan, A. Cyclability Study of Silicon−Carbon Composite Anodes for Lithium-Ion Batteries Uusing Electrochemical Impedance Spectroscopy. Electrochim. Acta 2011, 56, 3981−3987. (28) Son, I. H.; Park, J. H.; Kwon, S.; Park, S.; Rümmeli, M. H.; Bachmatiuk, A.; Song, H. J.; Ku, J.; Choi, J. W.; Choi, J.-m. Silicon Carbide-Free Graphene Growth on Silicon for Lithium-Ion Battery With High Volumetric Energy Density. Nat. Commun. 2015, 6, 7393.
H
DOI: 10.1021/acsami.7b10639 ACS Appl. Mater. Interfaces XXXX, XXX, XXX−XXX
