Heading towards novel superior silicon-based lithium-ion batteries: ultrasmall nanoclusters top-down dispersed over synthetic graphite flakes as binary hybrid anodes

Abstract

A prominent anodic material of silicon ultranano-particles (SiUPs, size < 10 nm) using recycled Si wafer fractures as raw materials and further improvement called top-down dispersion for high-capacitive Li-ion batteries has been addressed originally in this work. Economic benefits and outstanding electrochemical properties, including shorter Li-ion diffusive paths and low-strained effects as a result of the unique ultra-nanometric structure, enable such SiUPs to possess superior advantages for scalable manufacturing procedures as compared to other nanometric Si powders and become the priority of starting materials for Si-based anodes potentially. Meanwhile, an advanced top-down dispersive process has been optimized systematically to prevent severe particle aggregation to ameliorate the electrochemical performance of SiUP electrodes. In addition to avoiding pre-aggregation, this top-down dispersion brings in adequate buffer spaces, constructed by dispersive media (graphite flakes) and well-dispersive ultrasmall SiUP nanoclusters (size < 100 nm), alleviating drastic volume variation and local stress during cycling. These improved SiUP electrodes maintained 1200 mA h g⁻¹ specific capacity over 300 cycles at a high current density of 0.8 A g⁻¹, coupled with ca. 98.5% reversibility. On the basis of these advantages, including low cost, facile manufacture and high performance, this original method provides a pathway to achieve commercial high-capacitive Si–C composite anodes for Li-ion batteries.