Vacancy Ordered Lead Free Double Perovskite Based Flexible Supercapacitor for Sustainable Energy Applications

Abstract

Due to their extraordinary photophysical properties, lead halide perovskites are widely used in optoelectronics and energy applications. These distinctive materials have exceptional ionic responses because of halide ions and A-site cations. However, the lead toxicity along with ion kinetics in halide perovskites leads to structural deformation and instability, preventing these materials from commercialization. In this article, we have explored the possible application of vacancy-ordered tin-based lead-free double perovskite (A 2 BX 6 ) in energy storage devices. We have further tuned the X-site anion (X = I, Br, Cl) to see the effect of halide ions on the supercapacitor properties. The Cs 2 SnI 6 -based electrode has the highest specific capacitance (∼420 F/g) and energy density (∼200 W h/kg) as estimated from the three-electrode half-cell measurement system. Solid-state devices were also fabricated using gel electrolytes. We have achieved areal capacitance over 10 mF/ cm 2 , while energy density and power density are 3.2 μW h/cm 2 at 0.2 mA/cm 2 and 670 μW/cm 2 at 0.75 mA/cm 2 current density, respectively. We also achieved a maximum voltage window over 1.8 V for the Cs 2 SnI 6 sample. Various fundamental characterizations such as ex situ XRD, FTIR, and XPS measurements are carried out to understand the charge storage mechanism in vacancy-ordered perovskite structures.

Air-Processed All-Inorganic Halide Perovskites Integrated Photorechargeable Supercapacitors

“…High light absorption coefficient, low carrier recombination rate, and micron-scale carrier diffusion length are some of the unique benefits of halide perovskite that enable high PCE in perovskite solar cells. − Recently, perovskite-based solid-state supercapacitors have been reported to have excellent stability and efficiency. − Therefore, it is possible to integrate a perovskite solar cell and a perovskite supercapacitor into a monolithic structure, enhancing the performance of the integrated device at a reduced cost. Several high-performance supercapacitor materials reported in the literature could be potential candidates for integrated photo rechargeable supercapacitors.…”