Researchers from the Indian Institute of Technology Roorkee and the University of Massachusetts Amherst have developed perovskite-based photo-rechargeable supercapacitors.
The team explained in the study that current approaches for off-grid power separate the processes for energy conversion from energy storage. However, with the right balance between the electronic and ionic conductivity and a semiconductor that can absorb light in the solar spectrum, it is possible to combine energy harvesting with storage into a single photoelectrochemical energy storage device. In their new work, the researchers reported such a device - a halide perovskite-based photorechargeable supercapacitor that simultaneously harvests and stores energy.
This device can be charged with an energy density of 30.71 W h kg–1 and a power density of 1875 W kg–1. The team reported a method for fabricating efficient photorechargeable supercapacitors with a photocharging conversion efficiency (η) of ∼0.02% and a photoenergy density of ∼160 mW h kg–1 under a 20 mW cm–2 intensity white light source.
Halide perovskites have a high absorption coefficient, large carrier diffusion length, and high ionic conductivity, while the electronic conductivity is improved significantly by mixing carbon black in porous perovskite electrodes to achieve efficient photorechargeable supercapacitors.
The researchers also detailed their in-depth analysis of the photoelectrode to understand the working principles, stability, limitations, and prospects of halide perovskite-based photorechargeable supercapacitors.