CeO2/MnOx@C hollow cathode derived from self-assembly of Ce-Mn-MOFs for high-performance aqueous zinc-ion batteries

Abstract

The construction of composite materials is an effective strategy to solve the problems of poor conductivity, manganese dissolution, and volume expansion of manganese-based materials. Herein, a CeO2/MnOx@C hollow composite cathode derived from the self-assembly of Ce-Mn-metal-organic frameworks (Ce-Mn-MOFs) was synthesized. The abundant oxygen vacancies and good electronic/ionic conductivity of CeO2 improve the electrical conductivity of composite, enhancing the rate performance. The unique hollow structure could inhibit manganese dissolution and alleviate volume expansion. The results indicate that the 1 % CeO2/MnOx@C composite cathode possesses a high reversible capacity and excellent cycling stability. Specifically, the 1 % CeO2/MnOx@C composite cathode shows a remarkable reversible specific capacity of 130 mAh/g at a current density of 500 mA g−1, 6.5 times more than the pure MnOx (20 mAh/g). The capacity retention is up to 99.5 % relative to the initial capacity after 800 cycles. This study provides a new strategy for designing rare-earth composite electrodes to improve electrochemical performance.