Flexible all-solid-state supercapacitor with boosted energy density based on Ni(OH)2/nanoporous Ni composite electrodes

Abstract

This work successfully synthesizes an integrated flexible-porous Ni(OH)₂/nanoporous-Ni (Ni(OH)₂/np-Ni) composite electrode by a facile and eco-friendly one-step water-immersion approach. As such, the symmetric banded all-solid-state supercapacitor (BFAS) device assembled by Ni(OH)₂/np-Ni exhibits impressive energy density (41.4 mWh cm⁻³) and outstanding cyclic durability (93% after 3000 cycles). Significantly, the device maintains the flexibility of electrode materials and can be curved into bent, round, and waved while preserving excellent electrochemical performance under various bending. Even after 800 continuous bends, the capacitance retention rate still reaches 88%. Moreover, illuminating a LED with an all-solid-state supercapacitor demonstrates the practical viability of both the design approach and employed materials in a commercial context.