A SiOC anode material derived from PVA-modified polysiloxane with improved Li-storage cycling stability

Abstract

A silicon oxycarbide (SiOC) material was prepared by high-temperature pyrolysis of polyvinyl alcohol (PVA)-modified polysiloxane using phenyltriethoxysilane (PhTES) as raw material and PVA as a composition-modifying additive via sol–gel route, and characterized as an anode material for Li-ion batteries. This modified SiOC material demonstrates superior electrochemical performance to the pristine SiOC material in terms of reversible specific capacity, rate performance, and cycling stability, especially for the significantly improved cycling stability. Long-term cycling test result shows that the initial reversible charge specific capacity delivered at the current density of 100 mA g−1 is 515.2 mAh g−1. After 150 cycles, a capacity of 504.6 mAh g−1 is still remained, giving capacity retention of 97.9%. The improved electrochemical performance is attributed to the increased carbon content and enhanced electrical conductivity as well as the changed morphology of the modified material due to the composition modification of the polymer pre-ceramics.