Facile construction of ZnMn2O4 nanosheets via alcohol solvothermal zinc ion-exchange reaction for high-performance lithium-ion batteries

Ternary metal oxides are acknowledged as potential electrode materials for lithium-ion batteries on account of their conspicuous electrochemical properties. Regulating internal morphology structure of materials is conducive to achieving the best electrochemical performance. Among them, two-dimensional nano-metal oxides with high specific surface areas and excellent electronic conductivity have been actively developed. In this work, utilizing pleated manganese-based nanosheets as templates, ternary spinel-structured ZnMn₂O₄ nanosheets were successfully synthesized using a straightforward alcohol solvothermal zinc ion-exchange routine. When cycled at 500 mA g^{- 1}, ZnMn₂O₄ nanosheets, about 1.1 mg cm^{- 2} loading weight in electrode, have a specific capacity of 321.48 mAh g^{- 1} at the 100th cycle, along with an impressive Coulombic efficiency of about 100%, which obviously exceeds that of MnO₂. This is a great improvement on the electrochemical properties when zinc ions are introduced into manganese-based materials. Furthermore, ZnMn₂O₄ nanosheets, only 0.5 mg cm^{- 2} loading weight in electrode, own a superior discharge capacity of 1047 mAh g^{- 1} despite having undergone 200 cycles. Based on our researches, ZnMn₂O₄ nanosheets are identified as a high-specific-energy active material with exceptional lithium-storage performance and have potential practical value in LIBs.