Strain‐Modulated Engineering of High‐Entropy Vanadium‐Based Chalcogenide for Sustainable Water Oxidation

ABSTRACT High‐entropy metal chalcogenides (HEMC), stabilized by their high configurational entropy and multi‐element disorder, have emerged as promising materials for electrocatalysis. However, synthesizing high‐entropy sulfide catalysts via bottom‐up routes remains challenging due to the thermodynamic incompatibility of multiple metals, which promotes unwanted phase segregation and hinders controlled self‐assembly for optimal electrocatalytic performance. In this study, we tackle this challenge by systematically optimizing the solvothermal synthesis parameters, including solvent ratio, reductants, and stabilizers, to produce a single‐phase, strain‐engineered HEMC nanoflower/nanoflake (VMoFeCoNi)S _x , as strain engineering has the potential to modify the adsorption process and enhance electrocatalytic activity. The Williamson–Hall analysis reveals a compressive micro strain of 0.67%, manifested as a blue shift of the (220) reflection (44.34° → 44.47°) and a slight lattice contraction relative to the control samples. The optimized HEMC‐based anode exhibits top‐level oxygen evolution reaction (OER) performance in alkaline media, achieving overpotentials of 210 mV and 250 mV at current densities of 50 mA cm ⁻² and 100 mA cm ⁻² , respectively. Notably, it retains excellent OER stability with minimal degradation at 200 mA cm ⁻² over 120 h, demonstrating rapid reaction kinetics and durability at high current density, positioning it as a promising candidate for practical energy applications.