Portable integrated photo-charging storage device operating at 3 V

The integration of an energy harvesting device and an energy storage device into one unit has been widely studied as a distributed power source. Herein, we propose a high-voltage-driven photo-charging storage device, integrating a series-connected perovskite solar cell and an ionogel-based solid supercapacitor. The photo-charging storage device exhibits high overall efficiencies of 13.17 % and 9.87 % at 1 mA cm−2 and 20 mA cm−2, respectively, attributed to its high storage efficiency of over ∼ 70 % at all discharge current densities. This high discharge current density of 20 mA cm−2 is the record value for all reported integrated solar cells and electric double-layer capacitor systems. Moreover, the photo-charging storage device maintains 78.6 % of its overall efficiency after 100 cycles under AM 1.5 G illumination and exhibits remarkable cycle performance under indoor light illumination. To understand the interfacial behavior of the photo-charging storage device, impedance spectroscopy is performed for the first time. In addition, to avoid the decomposition of the perovskite solar cell active layer with moisture, an encapsulation process is conducted, which enables the device to remain operational at 3 V after 8 weeks. These results underline the high potential of this photo-charging storage device as a portable power source.