???????Flexible Zn-ion hybrid supercapacitor enabled by N-Doped MnO2 cathode with high energy density and ultra-long cycle life

To meet the higher requirements for green energy, high-performance renewable energy technology based on earth-abundant materials is essential. Aqueous zinc-ion hybrid supercapacitors (ZSC) have been re-garded as an attractive candidate for sustainable electrochemical energy storage device combining the advantages of batteries and supercapacitors, but their unsatisfactory cycling stability and low energy density remain a problem to be solved. Herein, nitrogen-doped MnO2 (N-MnO2) nanowalls were synthesized by in situ deposition, which provides rich ion transport pathway and accelerates the extraction/in-sertion of zinc ions. As a result, N-MnO2 anode can be assembled to an aqueous zinc-ion hybrid capacitor with AC cathodes, presenting a high energy density of 712.5 mu Wh cm-2 at a power density of 1000 mu W cm(-2) (1 mA cm(-2)) and excellent cycle stability with a capacity retention rate of 92.9 % in 25,000 charge-discharge cycles. In addition, the flexible hybrid supercapacitor exhibits excellent mechanical flexibility, and the electrochemical performance remains stable under different bending angles. This work shows that ZSC device based on N-MnO2 nanowalls hold great potential for new energy storage devices.(c) 2022 Elsevier B.V. All rights reserved.