Efficient interface engineering on the NiO/FeCo2O4 electrode for boosting photo-assisted supercapacitor performance

Photo-assisted energy storage devices provide an appropriate way to recognize the utilization of the unlimited solar energy. Herein, we construct the photoresponsive heterogeneous interfaces between NiO and FeCo2O4 to improve the performance for photo-assisted supercapacitor. As expected, the NiO/FeCo2O4 electrodes exhibit ultrahigh energy storage capacity of 7933 F g−1 at 1 A g−1 irradiating by simulated sunlight. In addition, a NiO/FeCo2O4//AC asymmetric supercapacitor is assembled, whose energy density is enhanced from 35.6 Wh kg−1 to 61.9 Wh kg−1 at the power density of 1.5 kW kg−1 under light. Combining with density functional theory (DFT) calculations, it is discovered that the photo-generated electrons would transfer from NiO to FeCo2O4, and then inject into the external circuit. Meanwhile, the photo-generated holes participate the charging process. This work provides a theoretical basis for effectively building heterogeneous interfaces to storage the abundant solar energy.