Cobalt-doped β-Ni(OH)2 electrode fabricated by in-situ chemical corrosion for photo-assisted supercapacitor with low-temperature operation

The integration of photosensitive electrode materials with excellent electron and ion transfer dynamics provides an effective strategy to address the unsatisfactory low temperature tolerance of energy storage devices. Here, the surface morphology reconstruction derived from the in-situ chemical corrosion of nickel foam (NF) endow the Co-doped β-Ni(OH)2 electrode material excellent electrolyte contact and more exposed active surface, showing the super area specific capacity under illumination (15.01 F/cm2 at 60 mA/cm2), which is three times higher than that without illumination (5.29 F/cm2 at 60 mA/cm2) at room temperature. The energy density of the assembled asymmetric photoassisted supercapacitor (ASC) reaches 1.85 mWh/cm2 at a power density of 36.01 mW/cm2 under illumination, increased by 94.7 % compared to that without illumination at room temperature. Benefiting from the excellent photoelectric and photothermal conversion ability of the electrodes, the energy density of ASC can reach up to 0.63 mWh/cm2 with a power density of 34.94 mW/cm2 under illumination even at a low temperature of −40 °C, demonstrating the potential application of the wide temperature range of the supercapacitor.