Novel composite cathode material α-MnO2@ZIF-67 for high performance aqueous rechargeable Zn-ion battery

Abstract

As a promising cathode material for aqueous zinc ion batteries, manganese dioxide (α-MnO2) faces several challenges such as low ionic conductivity and significant volume expansion during charging and discharging. Coating is an effective method to improve the electrochemical performance, and the composition and structure of the coating layer play a key role in the electrochemical properties of the materials. In this work, we employed a room temperature in situ growth strategy to fabricate composites comprising α-MnO2 nanorods and Zeolite Imidazolium Framework-67 (ZIF-67) nanoparticles. The porous ZIF-67 improves the ionic/electronic conductivity and provides more active sites. The α-MnO2@ZIF-67 composites show a high specific capacity of 313.4 mAh g−1 at 100 mA g−1 and good long-term cycling stability, with a capacity retention of 65 % after 1500 cycles at 1000 mA g−1. The above results indicate that it is an effective technique to improve the electrochemical performance of manganese-based oxide materials by compositing with porous MOFs.