Integrating a redox-coupled FeSe2/N-C photoelectrode into potassium ion hybrid capacitors for photoassisted charging

With a high-energy density and high-power output, potassium ion hybrid capacitors (PIHCs) are promising next-generation energy storage devices. However, the poor K+ electrochemical performance of battery-type anodes remains a challenge due to the inherent insulating property and the poor ion-transport kinetic of the anode materials. Herein, we report an integrated photoelectrode to achieve significantly enhanced K+ storage performance. The electron-hole pairs generated by the integrated photoelectrode under light-irradiation synergistically enhance the electrochemical adsorption of K+ and reversible ion-transport kinetics. Specifically, in the presence of Z907 dye that matches the energy level of the FeSe2 integrated anode, the reaction energy barrier during illumination was significantly reduced by 35.7% (similar to 0.05 eV). A remarkable increase in capacitance is therefore achieved to 23.8% at 3 A g(-1) (under light). This discovery provides an effective pathway for breaking the energy density of PHIC only by the conversion and storage of solar energy.

Automated summary

An integrated photoelectrode is reported to achieve significantly enhanced K+ storage performance. Electron-hole pairs generated by the photoelectrode under light-irradiation enhance the electrochemical adsorption of K+ and reversible ion-transport kinetics, resulting in increased capacitance.