A hollow tubular NiCo layacknered double hydroxide@Ag nanowire structure for high-power-density flexible aqueous Ni//Zn battery

Flexible aqueous Ni//Zn batteries have attracted much attention as promising candidates for energy storage in the field of flexible electronics. However, the Ni-based cathodes still face the challenges of poor conductivity, confined charge/mass transfer, and non-flexibility. In this work, we designed a hollow tubular structure consisting of a conductive silver nanowire (AgNW) wrapped by active NiCo layered double hydroxide (LDH), for enhancing the electrical conductivity, improving the charge/mass transfer kinetics, and facilitating the ion penetration. By optimizing the contents of Ni, Co and AgNW, the Ni₄Co LDH@Ag_1.5NW composite shows a maximum specific capacity of 115.83 mAh g⁻¹ at 0.1 A g⁻¹ measured in a two-electrode system. Highlightingly, the flexible aqueous Ni//Zn battery assembled by Ni₄Co LDH@Ag_1.5NW interwoven with multi-walled carbon nanotube cathode and Zn foil anode realizes a high power density of 160 μW cm⁻² at the energy density of 23.14 μWh cm⁻², which is superior compared with those of oxide/hydroxide based devices and even higher than those of many carbon-based supercapacitors, showing its promising potentials for flexible energy storage applications.