Boosting the Local Temperature of Hybrid Prussian Blue/NiO Nanotubes by Solar Light: Effect on Energy Storage

Energy storage devices based on pseudocapacitive materials usually suffer from poor performance at lower temperatures. To address this challenge, in this study, we integrate a Prussian blue analog (PBA) shell on a pseudocapacitive material to achieve a remarkably improved capacitive performance by a solar light-induced heating effect. The capacitor material is prepared by growing a layer of nickel hexacyanoferrate nanocrystals on NiO nanotubes (NTs) via a simple anion-displacement reaction. The electrodes based on optimized PBA/NiO NTs not only exhibit an enhanced capacitance in a natural Li2SO4 aqueous electrolyte but also show a remarkable overall phototo-thermal conversion efficiency. Most importantly, the local surface temperature can rapidly increase from -4.0 degrees C to 45.6 degrees C by solar-light irradiation for only 30 min. Benefitting from the highly increased local temperature, the cation storage ability is highly improved, which shows 377.8% enhancement of specific capacitance at a coulombic efficiency higher than 100%. An asymmetric supercapacitor cell assembled using PBA/NiO NTs and active carbon exhibits distinct thermally enhanced capacitance, mechanical flexibility, and outstanding cycling performance of 15,000 cycles without any capacity decay, indicating the great potential in real application for antidecay of energy storage devices in cold weather. This design paves new pathways to utilize solar light to achieve a suitable working temperature for pseudocapacitors in a low temperature environment (down to approximately -4 degrees C), thus possessing great application potentials in the field of advanced energy storage devices.

Automated summary

This study integrates a Prussian blue analog (PBA) shell on a pseudocapacitive material to improve capacitive performance through solar light-induced heating. The optimized PBA/NiO NTs electrodes exhibit enhanced capacitance and overall phototo-thermal conversion efficiency. This design shows potential for advanced energy storage devices, with applications in cold weather environments.