A long service life silicon-doped laser-etched polyimide anode materials for high-rate lithium-ion battery

Abstract

Silicon (Si)-based materials emerge as promising anode materials owing to their theoretical capacity as high as 4200 mAh g−1. However, when Si-based materials are assembled into battery anode sheets, they face the dilemmas of severe volume expansion and poor electric conductivity. In this study, three-dimensional (3D) layered porous Si‑carbon (C) composites are designed and fabricated from a polyimide (PI) precursor through cyclization polymerization and laser etching. SiC particles are dispersed in the porous network structure, which reduces the volume expansion of the anode during charging and discharging, so that the electrode has good cycle life and specific capacity. The laser-etched Si-doped polyimide (L-Si-PI) anode achieves 1332 mAh g−1 capacity in the first discharge and a high capacity of 1057 mAh g−1 after 1500 cycles at 0.2 A g−1 for half lithium-ion batteries (LIBs). When the L-Si-PI is employed for full LIBs, it exhibits a specific capacity of 142 mAh g−1 at 0.1C with 800 cycles working life. And kinetic analysis reveals a diffusion-controlled lithium storage mechanism in the composite. In a word, such rational nanostructure design and multi-component synergic interaction system has a good application prospect in the field of LIB research.