Fabrication of organometallic halide perovskite electrochemical supercapacitors utilizing quasi-solid-state electrolytes for energy storage devices

Organometallic halide perovskite materials have gained enormous interest in energy conversion and various optoelectronics applications. These unique materials possess great ionic response. Hence, their suitability for energy storage device applications needs to be explored. We fabricated for the first time all-solid-state perovskite electrochemical supercapacitors with high areal capacitance, fast charge-discharge rate, high power density and superior cyclability. We investigated electrochemical energy storage performance of two different quasi-solid-state electrolytes sandwiched between two symmetric perovskite electrodes. We recorded highest areal capacitance of 21.50 μF/cm² which is 3.65 times greater than areal capacitance recorded by similar perovskite electrochemical capacitors utilizing liquid-state electrolytes. High power density of 5.05 W/cm² was achieved. Electrochemical impedance spectroscopy (EIS) was used to study the ionic transport mechanism and properties of our fabricated devices. The Nyquist plots exhibit linear characteristic across low and high frequency ranges, indicating excellent electrolytes diffusion into the perovskite electrodes and confirming ideal supercapacitor behavior of these devices. All devices exhibit short relaxation time with device having least relaxation time of 251.19 μs indicative of fast discharge properties of fabricated devices. Our devices show excellent cyclability with device retaining 98.34% of its initial capacitance after 1000 cycles.