Si/TiSi2/G@void@C composite with good electrochemical performance as anode of lithium ion batteries

Abstract

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.