Electrochemical Evaluation of the Stability and Capacity of r‐GO‐Wrapped Copper Antimony Chalcogenide Anode for Li‐Ion battery

Abstract

Poor cycling stability and capacity fade are primary concerns for next‐generation anode materials for Li‐ion batteries. In non‐carbonaceous anode materials, alloying with Li leads to volume increase that affects practical applications, and increase in particle size, amorphization and reduced conductivity can all lead to a loss of performance. In this work, binary antimony sulfide (Sb2S3) and ternary copper antimony sulfide (CuSbS2) are synthesized by a convenient solvothermal process. These materials are used to study the Li‐active/inactive concept, by incorporating Cu into Sb2S3 forming CuSbS2 wherein Cu is Li inactive whereas Sb is Li active. By direct comparison, we have shown that incorporating Cu into binary antimony sulfide (Sb2S3) resulting into ternary copper antimony sulfide (CuSbS2) addresses the problem of poor conductivity and capacity loss, as Cu provides conductivity leading to enhanced charge transfer and prevents Sb particle aggregation while charge‐discharge by exhibiting spectator or diluent ion effect. The better performance of CuSbS2 is associated with the better Li+ ion diffusion in the CuSbS2 (D=8.97×10−15 cm2 s−1) compared to Sb2S3 (D=2.76×10−15 cm2 s−1) and lower series resistance of CuSbS2 (R=4.70×105 Ω) compared to Sb2S3 (R=5.81×108 Ω). We have also investigated the composite with the addition of rGO. The CuSbS2‐rGO delivered a reversible capacity of 672 mAh g−1 after 1000 cycles at 200 mA g−1 which has shown best performance.