Interfacial structuring of Mn[sbnd]N and Mn[sbnd]C bonds by defect engineering for high-performance Zn-Mn battery

Abstract

Zinc‑manganese batteries (ZMBs), with their non-flammable aqueous electrolyte and lower electrode material costs, offer a safer and more economical solution to the problem of energy intermittency. However, current ZMBs still face significant challenges, such as the presence of low electrical conductivity and poor structural stability of the manganese-based cathode, as well as unclear mechanisms of structural changes during charge storage. Here, we present a strategy to construct MnO2 containing MnC and MnN bonds (PAMO) by defect engineering and interface bonding design. This strategy benefits from the fact that MnN and MnC bonds can stabilize the structure and promote the interfacial dynamics of MnO2, thus effectively mitigating manganese dissolution. Meanwhile, the oxygen defects generated by interfacial bonding increase the electrical conductivity of MnO2. In addition, in terms of morphology and structure, the leafy vein-like secondary compartmentalized structure formed by PAMO provides more reactive sites for the redox reaction of MnO2, accelerating charge transfer and ion diffusion. The experimental results show that compared with pure MnO2 (326.8 mAh g−1), the capacity of PAMO material is enhanced by 30.1% (426.6 mAh g−1), and the battery still has 85.4% residual capacity (144.2–123.1 mAh g−1) after 6000 cycles, and coulombic efficiency is always maintained above 99.5%. This heterostructure design strategy of C- and N-doped MnO2 provides high electronic conductivity while playing an important role in improving structural stability.