Sulfur-doped enhanced ZnMn2O4 spinel for high-capacity zinc-ion batteries: Facilitating charge transfer

Abstract

ZnMn₂O₄ spinel is considered a promising cathode material for zinc-ion batteries due to its superior Zn²⁺ storage capability. However, the widespread utilization of ZnMn₂O₄ spinel as a high-capacity cathode material is impeded by its insufficient electrical conductivity. To tackle this limitation, we have employed a sulfur doping approach by substituting sulfur for oxygen atoms within the ZnMn₂O₄ lattice structure. After theoretical calculation, the charge exchange between metal Zn/Mn and surrounding coordinated atoms is enhanced after sulfur doping. The sulfur-doped ZnMn₂O₄ spinel effectively enhances the electrical conductivity, improving its electrochemical discharge capacity. Furthermore, the results reveals that a doping level of 20 % provided the greatest enhancement in capacitance, achieving a specific capacity of 220.1 mAh/g. This work improves the disadvantages of ZnMn₂O₄ at the atomic level and can provide ideas for the optimization and modification of spinel cathode materials.