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Silicon-based photovoltaic technology is helpful in reducing the cost of power generation; however, it suffers from economic losses and environmental pollution caused by silicon cutting waste. Herein, a hydrothermal method accompanied by heat treatment is proposed to take full advantage of the photovoltaic silicon cutting waste and biomass excrementum bombycis to fabricate flake-like porous Si@C (FP-Si@C) composite anodes for lithium-ion batteries (LIBs). The resulting FP-Si@C composite with a meso-macroporous structure can buffer the severe volume changes and facilitate electrolyte penetration. Meanwhile, the slightly graphitic carbon with high electrical conductivity and mechanical strength tightly surrounds the Si nanoflakes, which not only contributes to the ion/electron transport but also maintains the electrode structural integrity during the repeated lithiation/delithiation process. Accordingly, the synergistic effect of the unique structure of FP-Si@C composite contributes to a high discharge specific capacity of 1322 mAh g−1 at 0.1 A g−1, superior cycle stability with a capacity retention of 70.8% after 100 cycles, and excellent rate performance with a reversible capacity of 406 mAh g−1 at 1.0 A g−1. This work provides an easy and cost-effective approach to achieving the high-value application of photovoltaic silicon cutting waste, as well as obtaining high-performance Si-based anodes for LIBs. [ABSTRACT FROM AUTHOR]

Silicon/carbon (Si/C) composites have become the mainstream anodes for silicon-based lithium-ion batteries (LIBs) with outstanding stability and high capacity, in which carbon can significantly stabilize the silicon anodes. Currently, most Si/C composites use nano‑silicon as raw materials, which suffer from low energy density, high price and preparation complexity. Here, we have developed a silicon-graphite‑carbon ternary composite (Si-G-C-15) with cheap micron-sized silicon as raw materials. It was prepared by ball-milling of micron silicon and graphite and subsequent carbonization of PAN, followed by NaOH selective etching. Electrochemical test results demonstrate that Si-G-C-15 can possess a reversible capacity of 965 mAh/g at 200 mA/g, with a capacity retention of 71.34% and 786 mAh/g at a high current density of 1 A/g after 100 cycles. Notably, this facile preparation process of silicon anodes with high rates and good capacity stability highlights the potential practical application. [Display omitted] • A facile routine is developed to fabricate silicon-graphite-carbon ternary composite. • Silicon anode using micro-sized silicon is low-cost and has high energy density. • NaOH etching method is powerful to improve electrode cycling stability and rate capability. [ABSTRACT FROM AUTHOR]

Silicon can be used in a variety of applications. Particularly, silicon particles are attracting increased attention as energy storage materials for lithium-ion batteries. However, silicon has a limited cycling performance owing to its peeling from the current collector and the volume expansion that occurs during alloying with lithium in the charging process. Significant contributors to this problem are the even distribution of silicon nanoparticles within the carbon matrix and their deep placement in the internal structure. In this study, we synthesized silicon nanoparticles and carbon materials via a bottom-up approach using a new method called plasma in solution. Silicon nanoparticles and the carbon matrix were synthesized in a structure similar to carbon black. It was confirmed that the silicon particles were evenly distributed in the carbon matrix. In addition, the evaluation of the electrochemical performance of the silicon–carbon matrix (Si–C) composite material showed that it exhibited stable cycling performance with high reversible capacity. [ABSTRACT FROM AUTHOR]