Robust ring-interlocked nanowire-engineered stratified porous CuxO/np-CuNiO electrodes with exceptional cycling durability under illumination

Abstract

To address the poor cycling stability of photo-assisted supercapacitors under light illumination, this work rationally synthesizes self-standing stratified porous photoelectrodes (namely CuxO/np-CuNiO, x = 1, 2) with robust structural durability and markedly improved cycling stability, via a sequentially engineered design. By precisely tuning critical anodization parameters, clustered CuxO nanowires are transformed into a reinforced ring-interlocked nanowire network, which greatly improves structural stability and facilitates efficient light harvesting. The photoelectrode with ring-interlocked CuxO nanowires possesses an excellent volumetric specific capacitance of 1124.20F cm−3 at 1 A cm−3 under light illumination, attaining a 39 % capacitance enhancement compared with the dark condition. Impressively, it delivers remarkable cyclic performance, with 89 % capacitance retention after 5000 light-irradiated cycles, surpassing the 2000-cycle lifetime of the original clustered nanowire structure. Moreover, the band structure and charge transport pathways of the NiO/Cu2O heterojunction are briefly illustrated in this work.