Constructing hollowly bimetallic selenides as cathode for aqueous zinc battery with outstanding rate performance

Abstract

Electrode materials with hollow micro-nanostructure have exhibited exciting promise in the field of advanced energy storage devices. Herein, a template-free strategy based on the Kirkendall effect was presented to synthesize a self-supporting bimetallic selenide with hollow nanostructure as a cathode for an aqueous zinc-based battery (AZBB). This strategy discards the tedious template introduction and removal process in the traditional design of hollow micro nano structures, as well as the poor conductivity and dead volume caused by plenty of adhesives when the active materials are coated on the collector. The prepared hollow Ni3Se4/CoSe2 on carbon cloth (H-NiCoSe/CC) cathode shows impressive specific capacity (405.8 mAh/g at 1A/g) and rate properties (300.2 mAh/g at 30 A/g). The assembled flexible AZBB composed of H-NiCoSe/CC cathode, Zn anode, and alkaline hydrogel electrolyte exhibits an ultra-high energy density of 557.0 W h kg−1 and highly long cycle (about 80.0 % retention after 3000 cycles). This work provides a brand-new outlet to fabricate hollow metal selenide electrodes for potential applications in energy storage devices.