Two-dimensional, P-doped Si/SiOx alternating veneer-like microparticles for high-capacity lithium-ion battery composite

Abstract

Si is a promising candidate for next-generation anode materials in lithium rechargeable batteries as it has a high theoretical specific capacity. However, mechanical damage due to volume changes during electrochemical cycling and low electrical conductivity are critical limitations for practical anode applications. Herein, a novel microscale 2D active material with alternating layers of Si and silicon oxide is developed, and its energy storage properties are investigated by fabricating a composite anode with conventional graphite. The composite anode shows improved specific capacity by the introduction of veneer-shaped Si microparticles and 88% capacity retention after 200 charge-discharge cycles. The adequate thickness of the layers and the repeating buffering layer existence in the high aspect-ratio microscale particles that mimic a 2D nanostructure minimized the volume changes of the Si-based electrode during cycling while achieving high electrical conductivity. This strategy can provide fundamental breakthroughs in overcoming the existing limitations of Si-based materials for the development of high-energy-density active materials for Li batteries.