Photocapacitor integrating perovskite solar cell and symmetrical supercapacitor generating a conversion storage efficiency over 20 %

Solar energy is clean, open, and infinite, but solar radiation on the earth is fluctuating, intermittent, and unstable. So, the sustainable utilization of solar energy needs the complementary combination of high-efficient energy conversion and low-loss energy storage technologies. Hence, a photocapacitor integrated with photo-electrical conversion and electric-chemical storage functions in single device is a cost-effective, volume-effective and functional-effective optimal choice. However, the highest reported conversion storage efficiency of single device is less than 13 %. Here, we investigate the relationship among various efficiencies of photocapacitors during conversion storage process, and propose a function portfolio management concept. Accordingly, a three-terminal photocapacitor integrated with perovskite solar cell and symmetrical supercapacitor units is designed. By harmonizing the energy matching between conversion and storage units and seeking the maximum power points coincide and the maximum efficiency points synchronize, the solar energy conversion storage efficiency of the integrated photocapacitor surpasses milestone of 20 %.