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Massive silicon (Si) waste is generated during the diamond wire cutting process in the photovoltaic industry. Recycling the Si waste to prepare anode materials for lithium-ion batteries is an important way to realize its value-increment utilization. However, controlled preparation of a waste-derived Si/C anode with superior performance still remains a great challenge. Herein, focusing on the pristine sheet-like morphology of Si waste from diamond wire cutting, Mg reduction is employed to reduce the size in the lamellar direction to form a sheet-stacked structure. Combined with CO 2 -derived carbon coating, a sheet-stacked Si/C composite anode with a porous structure is successfully constructed via subtle optimization of the Mg reduction time. The optimized Si/C electrode can release a remaining capacity of 693 mA h g −1 after 300 cycles at 1.0 A g −1 . This work provides an efficient way for recycling Si waste as anode materials for LIBs.

Silicon anode has been vigorously developed as an up-and-coming candidate for anode materials of lithium ion batteries, as it is featured by the sizeable theoretical capacity and resource superiority. However, it cannot be unrestrictedly adopted in practice because of the enormous volumetric change during the process of lithiation–delithiation again and again, as well as the low electrical conductivity. Herein, we expect to solve its intrinsic weakness through a synergy strategy that combines metal alloying, cavity structure, and carbon compositing. Si/TiSi2/G@void@C (STGvC) composites were designed and synthesized by induction melting and mechanical ball milling methods, adopting silicon waste produced in the photovoltaic industry and titanium-bearing blast furnace slag produced in the steel industry as raw materials. Meanwhile, the synthesis employs NaCl as a pore-forming agent, and polyvinyl pyrrolidon and waste graphite as carbon sources. As a result, the optimized STGvC sample with adding appropriate amount of NaCl harvests favorable cycling performance. It still records a discharge capacity of 886.6 mAh g−1 after 300 cycles during the circulating process at 1600 mA g−1. This investigation presents a unique strategy to prepare Si-based anodes with bright future and makes the effective utilization of industrial solid waste in the battery industry possible.

Silicon is considered to be the most promising anode material for the next generation of lithium-ion batteries (LIBs), but its application is limited by the severe capacity decline due to volume expansion of up to 300%. Considering the inward accumulation of the stress produced during the actual lithiation process and the stabilizing effect of oxygen element, structural design and surface oxygen content regulation work together to improve the cyclic stability of silicon. Herein, we report the design and construction of novel porous silicon materials with regulated pore structure and surface oxygen content. The facile strategy for the synthesis of the materials is using Mg 2 Si and tetraethyl orthosilicate (TEOS) as Si resource, and the oxygen in the feedstock is ingeniously used at the same time. A series of Si anode materials with different pore structure and surface oxygen content were obtained by adjusting the proportion of Mg 2 Si and TEOS. Using 0.5 g of Mg 2 Si and 1 g of TEOS to prepare the material, the electrode reaches the optimum electrochemical performance with a discharge capacity of 935.9 mAh g −1 after 100 cycles and 587.2 mAh g −1 after 300 cycles at 0.5 and 1 A g −1 , respectively. This work provides a new strategy for the design and preparation to boost stable lithium ion storage of silicon anode materials.

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