N-doped δ-MnO2 coated N-doped carbon cloth as stable cathode for aqueous zinc-ion batteries

Abstract

The rapidly growing demand for energy storage has led to an increasing interest in advanced batteries. Aqueous-based rechargeable zinc-ion batteries have attracted considerable attention owing to their low cost, good safety, and environmental friendliness. MnO2 is a promising cathode material for zinc ion batteries; however, its application is severely restricted because of its poor electrical conductivity and manganese dissolution. Herein, a nitrogen-doped layered δ-manganese dioxide coated on nitrogen-doped carbon cloth (N-CC@N-MnO2) is developed as a cathode material for zinc ion batteries via a facile hydrothermal method. Nitrogen doping in MnO2 effectively improves its oxygen vacancy concentration. Consequently, this improves H+ adsorption to enhance the capacity storage; further, it inhibits manganese dissolution. N-CC@N-MnO2 delivers a high-capacity retention of 94.6% even after 2000 cycles at 0.1 A·g–1, whereas that of the counterpart without N-doping (CC@MnO2) is only 40.5% after 1000 cycles. Moreover, N-CC@N-MnO2 achieves a capacity of 402 mAh·g–1 compared with only 163.2 mAh·g–1 achieved by CC@MnO2.