Improving stability and reversibility of manganese dioxide cathode materials via nitrogen and sulfur doping for aqueous zinc ion batteries

Abstract

Manganese based oxides are one of the most promising cathode materials for secondary aqueous zinc ion batteries. However, its structural instability and slow reaction kinetics have hampered its large-scale application. Here, a rational nitrogen and sulfur diatomic doping strategy is suggested to enhance the electrochemical activity and reversibility of manganese dioxide. The nitrogen and sulfur-doped manganese dioxide (N-MnxOy-S) electrode material is synthesized by a simple hydrothermal approach combined with a low temperature vulcanization treatment. The electrode exhibits an excellent initial discharge capacity of 178 mA h g−1 at 1 A g−1. Even at a high rate of 2 A g−1, the capacity retention rate exceeds 90% for 3000 cycles. The large number of oxygen defects increases the storage sites for zinc ions, resulting in the excellent electrochemical properties of N-MnxOy-S. Additionally, the Mn-S and Mn-N bonds in N-MnxOy-S boost the interfacial dynamics of manganese dioxide, which can effectively reduce the dissolution of manganese and efficiently improve the electronic conductivity. The current study demonstrates that nitrogen and sulfur co-doping is a successful method for enhancing the electrochemical performance of manganese-based oxide cathodes, which serves as an important benchmark for the development of cathode materials appropriate for aqueous zinc ion batteries.