Silicon-Based Composite Negative Electrode Prepared from Recycled

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Silicon-Based Composite Negative Electrode Prepared from Recycled Silicon-Slicing Slurries and Lignin/Lignocellulose for Li-Ion Cells Che-Yu Chou, Jin-Rong Kuo, and Shi-Chern Yen ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.7b03887 • Publication Date (Web): 14 Mar 2018 Downloaded from http://pubs.acs.org on March 15, 2018

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ACS Sustainable Chemistry & Engineering

Silicon-Based Composite Negative Electrode Prepared from Recycled Silicon-Slicing Slurries and Lignin/Lignocellulose for Li-Ion Cells Che-Yu Chou, Jin-Rong Kuo, Shi-Chern Yen* Department of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan *

Correspondence and requests for materials should be addressed to Shi-Chern Yen.

([email protected])

ACS Paragon Plus Environment

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ABSTRACT A large amount of kerf loss silicon slurries has been produced in the photovoltaics industry by direct diamond-wire slicing. The high-purity silicon particles in the slurries are suitable for reutilization as anode materials for lithium-ion batteries. In this study silicon particles from the kerf loss of silicon ingot slicing, coupled with lignin or lignocellulose as carbon precursors, are employed to form carbon-silicon composite materials. A pyrolysis thermal treatment in the presence of argon was applied to carbonize the biomass on the silicon materials in order to increase the conductivity of silicon-based anodes. Due to the different carbonaceous precursors, the composites formed different structures. The lignin-silicon electrode with a carbon-coated structure delivered an initial charge capacity of up to 2286 mAh/g and retained 880 mAh/g after 51 cycles at 300 mA/g. On the other hand, the pyrolyzed lignocellulose formed an interconnected structure with silicon particles, providing extra space to accommodate Si volume variation. The composite electrode exhibited an outstanding cycle performance with a capacity retention of up to 83.4% after 51 cycles at 300 mA/g. It was found that the utilization of silicon slurries from industrial silicon kerf loss and of biomass resources as battery materials can be improved and applied in energy storage application.

Keywords: Biomass carbon precursors, Kerf loss silicon, Heat treatment, C-Si composite materials, Lithium-ion batteries.


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Introduction Lithium-ion batteries (LIBs) have been widely used as energy storage devices in applications such as electrical vehicles, electronic products and power backup devices1. Due to the high theoretical specific capacity (~3500 mAh/g) of the Li15Si4 alloy, silicon holds great potential for becoming a promising anode material in LIBs2. Although silicon possesses high theoretical specific capacity, the drastic four-fold volume expansion after Li alloying has limited the commercialization of Si-based anodes3. The volume expansion has been investigated by several studies4-5. This structural change of silicon causes pulverization, resulting in the loss of contact with the electronic paths to current collectors6. To mitigate this problem, various silicon particles and graphene or graphene oxide (GO) composites have been applied to enhance the cycling stability and the electrical conductivity of the electrodes7-9. Such graphene-Si composites show a sandwich-like stacking of Si particles and graphene sheets. This framework structure provided abundant space for Si particles to expand within the graphene sheets; thus, the composites exhibited a stable cycling performance9. These Si-GO composites mainly exploited the high-conductivity and robust features of graphene oxide to alleviate the volume expansion of silicon particles. However, the fabrication of graphene is energy intensive and requires several oxidation processes on graphite10-11. The strong oxidization agents are not environmentally friendly and inevitably increase the cost of mass production of graphene. Modifications of the silicon morphology have been proved to enhance the cycling ability of Sibased anode materials12-13. Especially, pristine silicon nanowire arrays enabling the 1-D diffusion pathway for Li atoms and offering facile strain relaxation have demonstrated significant cyclability without appreciable fracture. These nanostructured pillars indeed ameliorated the key problems of Si-based materials. However, synthesis of silicon nanowires mainly harnesses the


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vapor-liquid-solid method, which would limit the practical applications of this approach. Therefore, this crystal growth method may not be suitable for industrial mass production. Conversion of natural precursors to carbon graphite provides a relatively low-cost approach for the development of novel electrode materials from abundant natural sources such as lignin powders14-15, banana peels16, rice husks17-18 and cellulose19. These carbon transformation methods are performed via heat treatment to create a robust and porous graphitic structure with a high surface area. While such thermal treatment would meet the criteria for mass production, it is nevertheless still desirable to combine these natural carbon precursors with silicon particles to obtain a cost-effective composite material. The photovoltaic industry generates a large amount of kerf loss silicon during the wire sawing process. These silicon particles could be an abundant source of electrode materials from the perspective of a sustainable economy. In this study, we sought to develop a C-Si composite materials using silicon particles (~1 µm) obtained from slicing silicon ingots and incorporated with lignin or lignocellulose as the carbon precursor (Scheme 1). Among the prevailing electrode processing strategies7-8, 12, 14, we chose to use argon atmosphere pyrolysis as a practical approach for the manufacture of C-Si composite materials. The clear distinction between lignin and lignocellulose was elucidated by particle size distribution measurements and scanning electron microscopy. Furthermore, we investigated the effects of the carbon precursors on the electrochemical performance via cyclic voltammetry as well as electrochemical impedance spectroscopy. The results revealed that lignocellulose could not only offer a stable foundation but also serve as the conductive media for silicon particles. We believe such a combination of industrial by-products could promote a wider applications of energy storage technologies.


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Scheme 1. Schematic illustration of the preparation of C-Si composite materials. Materials and Methods Preparation of Composite Materials Both biomass materials used in this study were by-products from the local pulp industry. Lignin, as a fine brown powder, was derived from the acid hydrolysis process for the removal of hemicellulose and sodium. Lignocellulose (Arbocel BWW 40), as a white fiber, was insoluble in water and ethanol. The lignin and lignocellulose samples were placed into a tubular furnace to undergo two stages of pyrolysis: (1) argon atmosphere pyrolysis and (2) air atmosphere pyrolysis. The original sample weight and the sample weight between each stage were carefully measured to determine the carbon content in these two samples. The ratio of the original sample weight to the final sample weight was taken as impurities, and the weight loss during the second stage of pyrolysis was regarded as the carbon content. Silicon powders, from direct diamond-wire sawing slurries, were reclaimed and purified from the cutting slurries. The biomass carbon precursor (2.0 g), lignin or lignocellulose, was first dispersed in an ethanol solution by magnetic stirring, and then, an equal amount of Si powder (2.0 g) was added into the solution. The solution was stirred for 2 hours and was sonicated every


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30 min to ensure adequate dispersion. After two hours of mixing until the solution became more viscous, the mixture was brought to calcination at 600 °C under an argon atmosphere for 5 hours. Preparation of Electrode Pastes and Assembly of Coin Cells The as-obtained composite material was mixed with carbon black (KS-6, TIMICAL) as a conductive agent and styrene butadiene rubber and carboxymethyl cellulose as binders in the weight ratio of 80:10:5:5 to form an ethanol aqueous solution with a 20 wt. % solid content. The electrode slurry was magnetically stirred for 1 hour and was then cast on a copper sheet with a coating blade. The coated copper sheet was dried at 60 °C in vacuum oven (60 mbar) for 24 hours. After drying, the coated copper sheet was roller pressed and cut into a 13-mm disk. The mass loading of the electrodes was 1.1-1.5 mg/cm2. The coin cells (CR2032 type) were assembled in an argon-filled glove box and were composed of lithium metal as both the reference and counter electrodes, a 25-mm thick PE/PP/PE separator, and 1 M LiPF6 in ethylene carbonate (EC) and diethyl carbonate (DEC) (EC:DEC = 1:1 wt. %) with 2 wt. % vinylene carbonate additive (UBIQ Technology Co., Ltd) as the electrolyte. Material and Electrochemical Characterizations Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were performed using an FEI Nova NanoSEM 230 field emission microscope with an accelerating voltage of 5 kV to obtain the morphology of the materials. Thermo-gravimetric analysis (TGA, Rigaku Thermo plus2 system TG8120) was performed in air atmosphere at a rate of 10 °C/min from 27 to 1000 °C. The phase composition and crystalline structure were identified by powder X-ray diffraction (XRD, Ultima IV Rigaku) with Cu Kα X-ray radiation. The particle size distribution (PSD) was examined by a laser particle analyzer (LS230, Coulter). Electrochemical cycling tests were performed using an AcuTech Battery Automation Test Systems (Model: BAT-


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750B) in the CC (constant current)-CV (constant voltage) mode with a cut-off voltage between 15 and 1000 mV. A constant current at the rate of 300 mA/g was applied until the voltage reached 15 mV, and then, the mode was switched to the constant voltage mode until 10% of the applied current was attained. Cyclic voltammetry (CV) was conducted on Autolab PGSTAT30 (Metrohm) over the potential range of 0.00-1.20 V at a scan rate of 0.1 mV/s. Electrochemical impedance spectroscopy (EIS) was recorded using an Autolab FRA32M (Metrohm) instrument in the frequency range from 100 kHz to 0.1 Hz with the perturbation amplitude of 5 mV.

Result and Discussion Silicon and Carbon Precursor Characterizations The XRD pattern of the recycled silicon particles from the diamond-wire slicing silicon ingot process is displayed in Figure 1a. All characteristic peaks can be matched to the standard XRD pattern of silicon powder. This result corroborated that the silicon particles could be considered as nearly pristine crystalline silicon. The PSD of silicon powders and biomass carbon precursors is shown in Figure 1b. Lignin powders have the smallest particle size among these three materials, which can be matched to the sphere-like particles indicated in the SEM image (Figure 1c). The average particle size of lignin is 0.135 µm. The second peak of lignin in the PSD diagram may be attributed to the nature of agglomeration. Silicon particles demonstrated a mean size (~0.332 µm) larger than lignin powders. SEM images of the Si particles are shown in Figure 1d and 1e. These submicron Si particles exhibited a flakes shape, and the second peak was also the conglomerate of silicon particles. It is noteworthy that lignocellulose has an almost three hundred times larger particle size than that of silicon particles. These lignocellulose fibers, as shown in Figure 1f, showed no apparent transformation of the structure under calcination at


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600 °C. The lignin particles and silicon particles can be well dispersed in the ethanol solution, transforming a carbon-coated silicon into a C-Si hybrid. By contrast, lignocellulose cannot form a homogeneous solution, which would lead to a quite different combination of Si-C composite materials.

Figure 1. (a) XRD analysis of recycled silicon particles; (b) particle size distribution of lignin, lignocellulose and recycled Si; (c) SEM image of lignin particles; (d, e) SEM images of recycled silicon particles; (f) SEM image of lignocellulose fibers. Characterization of Composite Materials The TGA results for recycled silicon particles and composites materials are shown in Figure 2a. For recycled silicon particles, no obvious weight changes were observed until the temperature reached 600 °C. As the temperature rises, the sample weight of the recycled silicon increases steeply at approximately 780°C, indicating the formation of silicon dioxide. For both composites material, the mass retention shows little decrease at the early stage of heating


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between 100 and 340°C, which could be due to the evaporation of moisture, and then exhibited an appreciable weight loss at approximately 460°C, indicating the formation of gaseous reaction products due to the oxidation of carbon. This reduction of the sample weight was regarded as being related to the carbon content in the composite material, and the silicon content can be calculated from the remaining weight percentage. Hence, the lignin silicon composite contains approximately 25.0 wt. % carbon and 68.5 wt. % silicon; accordingly, the lignocellulose silicon composite contains 9.1 wt. % carbon and 89.2 wt. % silicon. On the basis of the above results, the theoretical specific capacity of the composite materials can be evaluated using the following equation: Capୗ୧ =

େୟ୮౪౥౪ ି୑ి ×େୟ୮ి

(1)

୑౏౟

where Cap୲୭୲ : specific capacity of active material (AM) (mAh/gAM) Capେ : specific capacity of carbon in active material (assume 300 mAh/gC) Capୗ୧ : specific capacity of Si in active material (mAh/gSi) Mେ : carbon content in active material (%, gC/gAM) Mୗ୧ : carbon content in active material (%, gSi/gAM)

The EDS analysis of the lignin silicon composite is shown in Figure 2b, and the SEM image of the lignin silicon composite is shown in Figure 2c. The elemental composition analysis indicated a silicon content of 48.83 wt. %, a carbon content of 40.57 wt. %, an oxygen content of 9.91 wt. % and a sodium content of 0.70 wt. %. As indicated by the arrow in Figure 2b, some silicon flakes were covered by an amorphous carbon layer to form a large conglomerate, while in Figure 2c, the other scattered Si flakes could be uncovered or partly carbon coated. The EDS analysis of the lignocellulos silicon composite is shown in Figure 2d, and the SEM image of the


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lignocellulose silicon composite is shown in Figure 2e. The element analysis showed a silicon content of 76.17 wt. %, a carbon content of 13.35 wt. % and an oxygen content of 10.47 wt. %. On the other hand, lignocellulose (Figures 2d & 2e) retains its original rod-shape after the calcination, and during the calcination, the silicon particles were embedded on the surface of the lignocellulose, which could explain the relatively higher amount of the silicon content in the EDS analysis. However, the EDS analyses of both composites could merely demonstrate the elemental composition of selected areas; therefore, in terms of the actual element composition, the results of TGA were more representative.

Figure 2. (a) TGA curves of recycled Si, lignin-Si and lignocellulose-Si; (b) EDS analysis of lignin-Si composite material; (c) SEM image of lignin-Si composite material; (d) EDS analysis of lignocellulose-Si composite material; (e) SEM image of lignocellulose-Si composite material. Electrochemical Characterization


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The cycling performances of the three electrodes are shown in Figure 3a. To compare the performances of these electrodes, we converted the data to the specific capacity with respect to the mass of silicon. The capacity retention was calculated as the ratio the delithiation capacity of the corresponding cycle number to the 1st delithiation capacity. All these electrodes showed a first lithiation capacity of ~3300 mAh/g. The recycled Si (R-Si) electrode showed a huge decay in the first cycle. The first lithiation (delithiation) capacity of the R-Si electrode is 3333 mAh/g (1195 mAh/g). The irreversible capacity is up to 2138 mAh/g, which can be attributed to the poor conductivity of the recycled silicon. Moreover, after 30 cycles, the specific capacity of the silicon electrode fell again, indicating that the severe volume change would destroy the electrode structure. With an initial lithiation (delithiation) capacity of 3286 mAh/g (2287 mAh/g), the lignin-silicon (Lig-Si) electrode, in which Si particles were covered by amorphous carbon possessed a relatively higher conductivity than that of the recycled Si electrode and therefore exhibits a two-time higher specific capacity in the battery cycling test. Despite the higher specific capacity, the Lig-Si electrode shows obvious capacity fading at the early stage of cycling. This capacity fading could still arise from the volume change of the silicon. In other words, the huge silicon expansion undermined the cycling life, even though these silicon flakes were covered by amorphous carbon. The lignocellulose-silicon (Si-LigCel) electrode, on the other hand, demonstrated a large irreversible capacity at the 1st cycle, which was similar to the cycling behavior of the recycled Si electrode. The 1st cycle lithiation capacity of the Si-LigCel electrode is 3407 mAh/g with an irreversible capacity of 2242 mAh/g. This could be explained by the structure of the composite materials, in which the silicon particles were located on the surface of the Si-LigCel electrode, while for the Lig-Si electrode, the Si particles were enveloped by amorphous carbon. The peculiar structure of the Si-LigCel electrode contribute to the longer


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cycle life of the Si-LigCel electrode. It is noteworthy that the specific capacity of the Si-LigCel electrode increased after the 1st cycle. Such a capacity increase may be attributed to the expansion of the silicon particles, leading to a close contact between active materials. After 51 cycling tests, the capacity retention values for the R-Si, Lig-Si and Si-LigCel electrodes were 14.4, 38.5 and 83.2% (based on the 1st delithiation capacity), respectively. The high capacity retention of the Si-LigCel electrode may contribute to the distinctive structure, enabling the Si particles to expand on these carbonized lignocellulose fibers and protecting the electrode structure from pulverization. As seen in Figures 3b and 3c, we speculated that these two kinds of structure can explain the differences in the cycling performances and voltage profiles. For the Lig-Si electrode (Figure 3b), after the heat treatment, the lignin-derived carbon can serve as a coating to enhance the overall conductivity, and hence, this electrode shows a higher initial capacity than the Si-LigCel electrode. Despite this higher initial capacity, the repeat swelling and shrinking would cause the excessive formation of a solid-electrolyte interphase (SEI) and the rupture of the electrode structure eventually, thus hampering the cycle life. For the Si-LigCel electrode (Figure 3c), on the other hand, the lignocellulose fibers may be only partially carbonized during the calcination, and the silicon particles could embed in such carbonized fibers. These partially carbonized fibers could act as a robust base to accommodate the significant volume changes. However, due to the partial carbonization, the Si-LigCel electrode had an unfavorable irreversible capacity. Furthermore, we examined the effect of the calcination temperature on the cycling performance of the Lig-Si and Si-LigCel electrode. Figure 3d shows the cycling performances of the Lig-Si and Si-LigCel electrodes calcinated at 800 °C. The SiLigCel electrode showed an initial lithiation capacity of 3206 mAh/g and an initial delithiation capacity of 2080 mAh/g, while the Lig-Si electrode only showed an initial lithiation capacity of


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2500 mAh/g and an initial delithiation capacity of 2066 mAh/g. Notably, the increase of the calcination temperature for lignocellulose-derived carbon treatment could effectively reduce the irreversible capacity. The electronic conductivity of the carbon pillar substrate increased due to the higher calcination temperature; thus, the reversible capacity was enhanced. However, for the Lig-Si electrode, despite better performance for the irreversible capacity, the reversible capacity showed no improvement. Additionally, there were fluctuations in the cycling curves of the LigSi electrode, and these fluctuations could be attributed to the thinner carbon coating on the silicon surface compared to the electrode calcinated at 600 °C.

Figure 3. (a) Cycling performance of lignin-silicon, lignocellulose-silicon and recycled silicon electrodes at the current density of 300 mA/g with a voltage window between 15 and 1000 mV (hollow: lithiation; solid: de-lithiation); (b) schematic drawing of the lignin-silicon electrode during cycling; (c) schematic drawing of the lignocellulose-silicon electrode during cycling; (d) cycling performance of lignocellulose-silicon and lignin-silicon electrodes calcined at 800 °C at


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the current density of 300 mA/g with a voltage window between 15 and 1000 mV (hollow: lithiation; solid: de-lithiation) Figure 4a shows the voltage profile of the Lig-Si electrode obtained at the current of 300 mA/g between 15 mV and 1000 mV. The horizontal lines at each end of the cycles were due to the constant voltage charge and discharge. Except for the 1st cycle, where the formation of a passive film or SEI caused a huge irreversible capacity20, the following cycles tended to stabilize with increasing number of cycles. Figure 4b shows the voltage profile of the Si-LigCel electrode obtained at a current of 300 mA/g. A voltage dip is observed before the flat voltage plateau, indicating the heterogeneous nucleation of lithium metal onto the silicon surface, and the nucleation overpotential of silicon was identified as approximately 14 mV21. As a result, the morphological difference between Lig-Si and Si-LigCel could be characterized according to the voltage profile. Moreover, silicon activation could be observed in these voltage curves, which can be matched to the capacity recovery of Si-LigCel in the first 20 cycles22. To the best of our knowledge, this activation process may be attributed to the expansion of the embedded silicon particles, leading to a closer contact and a greater involvement of the reactant. Figure 4c displays the voltage profile of the recycled silicon electrode. The voltage dip in the R-Si electrode is even sharper than that in the Si-LigCel electrode. This overshoot was reported as the nucleation of lithium on the copper surface, and the overpotential is ~40 mV21. The overpotential diminished in the later cycles because of the formation of SEI films and because the expansion of silicon particles would also cover the copper surface. The results for cyclic voltammetry of the three electrodes at the fourth cycle are shown in Figure 4d. For the Lig-Si electrode, the cathodic peak at 0.21 and 0.03 V could be regarded as the contribution of the carbon-coated silicon, indicating the transformation of crystalline Si into


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the LixSi phase23. In the anodic process, accordingly, the two peaks at 0.37 and 0.51 V correspond to the extraction of lithium from amorphous silicon23. For comparison, the CV plot of Si-LigCel (dashed line) shows no apparent peak at approximately 0.21 V and only the cathodic peak could be observed at approximately 0.01 V. Similarly, only peak was observed in the anodic process, and this may match that in the cathodic one. Moreover, the CV plot of the R-Si electrode (dotted line) demonstrated a similar distribution to that observed for the Si-LigCel one. Therefore, we believe that this distinction could be attributed to the morphology of the electrode, in which the silicon particles were located on the carbonized lignocellulose pillars. It is notable that the area of the Lig-Si electrode at the fourth cycle is higher than that of the others, and this may match the result of the cycling performance (Figure 3a).


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Figure 4. Cycling voltage profiles of three kinds of silicon electrodes at 300 mA/g in the applied potential range of 15-1000 mV: (a) lignin-silicon electrode; (b) lignocellulose-silicon electrode; (c) recycled silicon electrode. (d) CV plots for the recycled silicon, lignin-silicon and lignocellulose-silicon electrodes from 1.2 V to 0.0 V at 0.1 mV/s. To further interpret the differences in cycling performance between Lig-Si and Si-LigCel, we performed EIS analysis and equivalent circuit modeling. The equivalent circuit model is shown in Figure 5a, where RS, RSEI, Rint and Rct represent the resistance of the electrolyte, SEI films, electronic contact interphase and charge transfer, CPESEI, CPEint and CPEct represent the capacitance due to the accumulation of ions at the interface, and Wdiff is the Warburg impedance of solid diffusion24. The Nyquist plots of the Lig-Si and Si-LigCel electrodes are displayed in Figures 5b and Figure 5c, where the solid lines represent the fitting curves. Figure 5d shows the illustration of lithium transport from the electrolyte to active material. As depicted in the enlarged drawing, the lithium ions would pass through several interphases including the electrolyte, SEI films, and electronic contact interphase to reach the surface of the electrode, undergoing the charge transfer process. The lithium transport resistance within each medium was measured by EIS analysis, and the impedance was further fitted and interpreted using equivalent circuits. According to the observations from the SEM images, the major differences in the EIS analysis results of both electrodes should be mainly attributed to RSEI and Rint because these two values are highly related to the morphologies of the electrodes. The results of model fitting were summarize in Tables S1 and S2. Because the same electrolyte was used in this study, both electrodes had a similar amount of Rs (Figure S1). The RSEI of Lig-Si (Figure S2) revealed that the SEI films on the carbon surface of the Lig-Si was more penetrable for lithium than the silicon SEI films of the Si-LigCel. The Rint of both electrodes showed a decrease at the 7th cycle (Figure


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S3), suggesting that the expansion of silicon particles resulted in a closer contact between the active materials. However, the Rint of both electrodes increased gradually in the following cycles. Especially, for the Si-LigCel electrode, the increase of Rint revealed that silicon particles may fall off of the carbonized fibers. The Rct of both electrodes showed little difference (Figure S4), which may be attributed to the excellent conductivity of their carbon structure. The overall resistances of the Lig-Si and Si-LigCel electrodes were initially 23.9 and 33.5 Ω, respectively. In summary, after the 50 cycles of tests, the overall resistance of the former became 38.1 Ω; while that of the latter was 59.9 Ω. According to the overall resistance, we may conclude that the carbon layer coating indeed provided a lower overall resistance for the Lig-Si electrode and that the higher resistance of the Si-LigCel electrode resulted from the covering of the silicon particles.


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Figure 5. (a) Equivalent circuits used in this study; (b) Nyquist plots of lignin-Si electrode; (c) Nyquist plots of lignocellulose-Si electrode; (d) schematic drawing of lithium transport from electrolyte to electrode surface. Conclusions Two types of lignin-silicon and lignocellulose-silicon composites obtained via argon atmosphere pyrolysis have been investigated. The lignin-silicon had a carbon-coated silicon structure which was reported as a protocol to improve the cycling life. The specific capacity after 51 cycles was 881 mAh/g with 38.5% capacity retention; by contrast, lignocellulose-silicon had a silicon embedded carbon fiber structure and displayed a specific capacity of 955 mAh/g with 83.2% capacity retention. Moreover, the specific capacity of Si-LigCel at 800 °C was up to 1515 mAh/g, which is almost 1.6 times higher than that of Si-LigCel calcined at 600°C. This study showed that industrial by-products can be utilized in practical electrode materials with an effectiveness comparable to commercial grade silicon nanoparticles. The low-cost but highperformance materials provide an environmentally friendly route for potential practical applications.

ASSOCIATED CONTENT Supporting Information. Additional information on the results of equivalent circuits fitting and figures illustrating comparison of resistances at various cycles. Acknowledgments


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Table of Contents Graphic and Synopsis

An efficient method to turn industrial by-products into a high-capacity anode material for lithium-ion batteries.


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Silicon-Based Composite Negative Electrode Prepared from Recycled

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