Sb/C Composite Embedded in SiOC Buffer Matrix via Sb/MOF-Driven Dispersion Property for Novel Anode Material in Sodium-Ion Batteries

Abstract

Abstract Due to vast sodium reserves, sodium-ion batteries (SIBs) are more cost-efficient to produce than lithium-ion batteries. Therefore, they are actively researched as next-generation energy storage materials. Antimony (Sb) is a promising anode material for SIB owing to its high theoretical capacity (660 mA·h·g−1) and an appropriate sodiation voltage. However, due to the rapid volume change during sodium intercalation and deintercalation, cycling stability is poor, presenting a significant obstacle to the practical application of SIBs. Alleviating the Sb volume expansion throughout the charging and discharging processes is the key to the practical implementation of Sb-based anodes. Herein, Sb/C–SiOC composites are prepared using the hydrogen bonding-based adsorption properties of metal-organic frameworks (MOFs). First, Sb-MOFs are synthesized and uniformly dispersed in the SiOC precursor using the hydrogen bonding properties of Sb-MOFs. A simple pyrolysis technique is then used to produce Sb/C–SiOC composites wherein Sb/MOF-derived carbon is uniformly embedded in the SiOC matrix. The final product, the Sb/C–SiOC composites, exhibited significantly improved cycle performance, such as maintaining the initial capacity after 200 cycles by the SiOC matrix acting as a conductive buffer. Additionally, the presence of surface capacitively reactive MOF-derived mesoporous carbon and SiOC contributed to the improved rate performance. The hydrogen bond-based adsorption properties of the MOFs used in this study can be effectively applied to uniformly introduce a matrix or coating layer that relieves the volume expansion of high-capacity composite anodes, making it an effective strategy for developing alloy-based energy storage materials.