Holey nickel nanotube reticular network scaffold for high-performance flexible rechargeable Zn/MnO2 batteries

Abstract

Developing uniform and interconnected conductive networks is critically important for future electrochemical electrodes. Reticular holey metallic nanotube networks can be a competitive candidate for this purpose, taking the advantages of a large surface area (both inner and outer surface can host active material) and excellent mechanical flexibility. However, due to the limited available fabrication techniques, there have not been any report regarding the controllable and large-scale fabrication of such a structure. Herein, we report an industry-compatible fabrication method for highly interconnected and conductive network of holey nickel nanotube membrane (HNNM) for electrode conductive scaffold, which is highly conducive for mass and charge transfer and shows superior mechanical flexibility. The as-obtained HNNM presents a high surface area of 8.67 m2 g−1 and conductivity (∼10-1 Ω/□ with the thickness of 15 μm), which is superior than those of nickel foam, carbon cloth and stainless-steel mesh etc. By electrodepositing a thin layer of MnO2 on HNNM (HNNM@MnO2) as cathode, and Zn metal on HNNM (HNNM@Zn) as anode, an aqueous flexible rechargeable Zn/MnO2 battery was successfully assembled with a capacity of 275.5 mA h g−1 at 0.2 A g−1 and a working voltage of 1.38 V. Moreover, it achieves an energy density of 380.19 Wh kg−1 with a maximum power density of 1.38 kW kg−1 and a high capacity retention after 500 cycles, which represents a critical step forward toward environmentally benign, low cost, and high performance electrochemical energy storage for practical applications.