Incorporating Co Nanoparticles into SiOx Anodes for High-Performance Lithium-Ion Batteries

Silicon suboxide (SiOx) is recognized as a promising anode material for lithium-ion batteries (LIBs) because of its higher specific capacity in comparison to graphite and better capacity retention in comparison to pure Si. However, the immense volume expansion and formation of inert lithium oxide (Li2O) during repeated lithiation and delithiation largely impede its practical application. In this study, we propose a combined metal activation and N-doped carbon layer coating strategy to overcome these obstacles. Extensive experimental characterization and theoretical calculation results disclose that the incorporation of Co nanoparticles into SiOx can not only boost the charge transfer kinetics but also activate the reversible conversion of Li2O to provide additional capacity. By further incorporating an N-doped carbon layer on the SiOx surface, the volume expansion of SiOx is greatly suppressed. As a consequence, the regulated SiOx anode displays a high reversible specific capacity of 627.8 mA h g–1 after 100 cycles at 0.1 A g–1. By an increase in the current density to 1 A g–1, a reversible specific capacity of 495.4 mA h g–1 is retained after 500 cycles. This work provides an effective avenue to simultaneously activate the inert Li2O and inhibit the volume change for the SiOx anode, which is beneficial for further development of high-performance LIBs.