High-entropy oxides (HEOs) have recently emerged as promising materials for enhancing the performance of lithium-sulfur (LiS) batteries, owing to their strong adsorption capability toward lithium polysulfides (LPSs) and their catalytic activity in facilitating sulfur redox reactions. In this study, HEOs were engineered to optimize the solid-liquid-solid electrochemical conversion of sulfur to LPSs and their subsequent reversion. A sol-gel-derived HEO composed of six metal cations (Al, Mg, Fe, Cu, Ni, and Co) exhibited high crystalline structure, porous morphology, and uniform distribution of multiple catalytically active metal species, which collectively contributed to effective LPSs confinement and accelerated redox reactions at the cathode. Raman analysis confirmed a disordered cubic structure with diverse cation occupancy across various crystallographic sites. Notably, the synergistic effects of LiO and SNi bonds, formed through interactions between HEOs and LPSs, significantly mitigated LPSs shuttling. Specifically, [Al_0.30(MgFeCuNiCo)_0.70O] (HEO-A) and [Fe_0.30(AlMgFeCuNiCo)_0.70O] (HEO-F) demonstrated superior electrocatalytic activity toward LPSs conversion, delivering high initial discharge capacities of ~1062 mAh g⁻¹ and ~ 997 mAh g⁻¹, respectively. At a sulfur loading of ~1 mg cm⁻², HEO-A exhibited exceptional cycling stability over 200 galvanostatic charge/discharge (GCD) cycles at 0.5 C, retaining a specific discharge capacity of ~648 mAh g⁻¹, while HEO-F maintained ~416.8 mAh g⁻¹ with a minimal decay rate of 0.095 % per cycle. This study not only highlights the potential of HEOs as effective promoters for LPSs immobilization in LiS batteries but also establishes a foundation for their application in a wide range of energy conversion and storage systems.

High-entropy oxides (HEOs) have emerged as a promising class of materials for advanced energy storage and conversion technologies, owing to their unique configurational disorder, tunable electronic structures, and compositional flexibility. In this work, we developed a novel heterostructure catalyst by immobilizing HEO nanoparticles on graphene oxide (GO) nanosheets, demonstrating exceptional electrocatalytic performance and durability for the oxygen evolution reaction (OER). Comprehensive physicochemical characterization confirmed the formation of a crystalline HEO phase with uniform elemental distribution and strong interfacial bonding with the GO support. The excellent electrochemical response is attributed to the self-regulating electronic structure of HEOs, high concentration of oxygen vacancies and fine structure exposed to electrolytes. Among all prepared electrocatalysts, the optimum composition (HEO@GO-50) demonstrated outstanding OER activity with low overpotential (η) ∼303 mV, small Tafel slope 44.4 mVdec⁻¹, high exchange current density (J_o) 14.16 mAcm⁻², high double layer capacitance (C_dl) 21.35 mFcm⁻², large electrochemical surface area (ECSA) 355.83 cm², low charge transfer resistance (R_ct) 28.64 Ω, high turnover frequency (TOF) 1.033 s⁻¹ and current retention of 92 % over 10 h of chronoamperometric analysis. These parameters are very competitive with other transition metal oxide based electrocatalysts and noble metal oxides. Our findings suggest that HEO-GO hybrids could represent a promising approach for designing high-performance, noble-metal-free electrocatalysts for sustainable energy applications.