Synthesis of porous Si nanoparticles for high performances anode material in lithium-ion batteries

Abstract

As one of the most promising candidates for anode materials, Si-based electrodes can offer specific capacity an order of magnitude beyond that of conventional graphite. However, Si usually suffers from dramatic volume changes during cycling cause pulverization and capacity fade. The key to improving cycle life is to synthesize Si-based materials with suitable architectures and a rational design. Here, we developed an economical and efficient method to obtain porous Si nanoparticles from coal ash. The Si nanoparticles with several nanometers can significantly shorten ion/electron transportation paths and further avoid the cracking and pulverization induced by large volume changes, and the porous structure makes the penetration of electrolyte easier. After carbonization, the obtained porous Si nanoparticles@C exhibits excellent electrochemical performances, and the special capacity can stable at 750 mAh g−1 at 2.0 A g−1 after 200 cycles. When current density up to 6.0 A g−1, the reversible capacity is 565 mAh g−1. We believe this method will make it possible to facilitate the large-scale and low-cost production of porous Si nanoparticles, and contribute to the development of high-performance Si-based anode materials.