Unraveling the High-Rate Electrochemical Kinetics of CuSbS2 for Sodium Storage

Abstract

Antimony-based materials have gained significant attention as anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity and excellent rate performance. However, metal sulfides such as Cu2S and Sb2S3 exhibit an initial capacity drop followed by a subsequent capacity recovery. To address these challenges, copper antimony sulfide (CuSbS2) is synthesized and evaluated as an anode material for SIBs. The synthesized CuSbS2 effectively mitigates these capacity variations (330 mAhg-1 at 2.0 Ag-1 after 200th cycles) and demonstrates superior rate performance. Moreover, comprehensive electrochemical analyses, including the distribution of relaxation times (DRT) analysis from in situ electrochemical impedance spectroscopy (EIS), capacitive contribution assessment, and galvanostatic intermittent titration technique (GITT) measurements, confirm its improved kinetic properties compared to Sb2S3. This study provides valuable insights into the rational design of bimetallic sulfides and contributes to the advancement of electrochemical performance analysis and the development of high-performance SIB anode materials.