Dataset of "Photoactivity Enhancement by Electrochemical Activation of Bifunctional V2C@S MXene: Desirable Approach in Single-architecture High-rate Zinc-ion Solar Batteries"

Single-architecture solar battery energy storage devices which are capable of storing energy from solar energy harvesting in only one package, are being developed as the upcoming and future off-grid energy storage systems. In this research, we explore the photo-responsive characteristics and application of vanadium-based MXene in pouch zinc-ion solar batteries. In addition to the pristine V2CTx MXene, a sulfur-incorporated nanocomposite of V2CTx@S was synthesized via a reaction between exfoliated V2CTx MXene and sulfur at a high benign temperature to evaluate the efficiency of both as photocathodes for such state-of-the-art devices. Through the initial electrochemical charging activation, photoactivity of the V2CTx@S photocathode was enhanced significantly because of the formation of nanoscale vanadium oxide on the surface of conductive V2CTx MXene and the presence of sulfur element without losing the MXene nanolayered characteristics. The results of the pouch zinc-ion solar battery made by V2CTx@S indicate a specific capacity of 197 mAh g–1 at 1 A g–1 under illumination, compared to the dark condition with the amount of 114 mAh g–1 at 1 A g–1 (72.8% enhancement). Additionally, the V2CTx@S zinc-ion solar battery carried out a photo-charging voltage response of 700 mV, and a remarkable energy density of 255 Wh kg–1 at 1 A g–1 under illumination compared to dark conditions with the energy density of 150 Wh kg–1 at 1 A g‒1. Furthermore, a photoconversion efficiency of ≈2.04% was obtained in the pouch zinc-ion solar battery. Density functional theory studies supported these experimental findings by revealing that sulfur modification and vanadium oxide formation improve the electronic properties and light absorption capabilities of the pristine V2C MXene, contributing to its superior photocathodic performance. These great achievements in photo-electrochemical behaviors of V2CTx@S are due to the catalytic synergy of bifunctional MXene decorated with sulfur element, the formation of outer high-valence vanadium oxide, and inner conductive of V2CTx. The findings provide crucial insights into designing of highly efficient photocathode materials for advanced solar batteries.