Sulfur-doped reduced graphene oxide/Sb2S3 composite for superior lithium and sodium storage

Abstract

Graphene, with excellent electrical conductivity and high theoretical capacity, may be one of the promising anodes for rechargeable batteries. However, several drawbacks, such as low initial coulombic efficiency (ICE) and limited actual reversible capacity, hamper their further development. Herein, a sulfur-doped reduced graphene oxide (rGO)-based composite with low-content Sb2S3 is synthesized through in-situ sulfuration process, which can deliver excellent electrochemical performance (high reversible capacity of 997 mA h g−1 with ICE of 71.6% for lithium storage and 639 mA h g−1 with ICE of 63.9% for sodium storage at 100 mA g−1), much higher than those of sulfur-doped or bare rGO. According to the physical and electrochemical characterizations, the partial substitutions of C–O bonds with C–S in rGO can greatly reduce the irreversible consumption of lithium or sodium, the covalent-bonded sulfur dopants and the doped Sb2S3 nanoparticles are electrochemically active for reversible lithium and sodium storage, and also enhance the structure stability effectively, resulting in superior electrochemical performance.