A flexible axial Zn ion hybrid supercapacitor with high surface capacitance and long cycle life

Zn-ion hybrid supercapacitors (ZSC) have shown great potential as energy storage devices as they in-corporate the merits of rechargeable batteries and supercapacitors. However, the poor bendability, un-satisfied energy density and cycling stability are still challenging the practical application of ZSC. Herein, Zn-doped MnO2 nanowires (Zn-MnO2) binder-free cathodes is synthesized with the aid of a one-step hy-drothermal approach, which improves the lattice distortion caused by Zn hydrate ions and provided rich ion transport path. The Zn-MnO2 cathode was assembled with the active carbon (AC) anode into an axial ZSC, achieving a surface capacitance of 1300 mF cm-2 and an energy density of 722.2 mu Wh cm-2 at power density of 1.99 mW cm-2. After 20,000 charge/discharge cycles, a capacity retention rate of 83.75% and a coulombic efficiency of 100% were achieved, indicating excellent cycle stability of present device. In addition, this axial ZSC reveals exquisite mechanical flexibility and electrochemical stability, enabling continuously power smartphones under bending conditions. Present work suggests that ZSC devices based on Zn-MnO2 have excellent doable for business energy storage devices.(c) 2023 Elsevier B.V. All rights reserved.

Automated summary

Zn-doped MnO2 nanowires (Zn-MnO2) binder-free cathodes were synthesized via a hydrothermal approach, improving lattice distortion and providing ion transport paths. Assembled with an active carbon anode, the Zn-MnO2 cathode achieved a surface capacitance of 1300 mF cm-2 and an energy density of 722.2 mu Wh cm-2. The device exhibited excellent cycle stability with a capacity retention rate of 83.75% after 20,000 charge/discharge cycles. The axial ZSC also demonstrated mechanical flexibility and electrochemical stability, making it suitable for powering smartphones under bending conditions. This study suggests the potential of ZSC devices based on Zn-MnO2 for energy storage applications.