Entropy-driven multisite cooperativity in high-entropy CoNiCuMnMo MOF electrocatalyst for efficient lignin depolymerization toward high-power-density flow fuel cells at low temperature

High-entropy lattice distortion triggers strong charge redistribution. • Unusual Mo-C coordination creates highly electrophilic Mo 5.5+ centers. • This configuration enables ultrafast β-O-4 bond cleavage at low temperature. • Mediator-free lignin flow fuel cells deliver 545.48 mW cm −2 peak power. • Lignin oxidation efficiently replaces sluggish OER for green electricity. Low-temperature lignin flow fuel cells (LFFCs) offer sustainable green electricity generation but are hindered by the difficult degradation of lignin and sluggish electrode kinetics. Herein, a novel binder-free high-entropy metal-organic framework (HE-MOF) electrocatalyst containing five transition metals (Co, Ni, Cu, Mn, Mo) is grown on graphite felt (GF) via one-step solvothermal method to be efficient anodic catalyst for LFFC. The transition metal ions are uniformly and randomly distributed on the lattice sites of the HE-MOF, indicating the formation of single-phase solid solution without phase separation. Synchrotron XAFS spectroscopy reveals that high-entropy effect triggers severe local lattice distortions and profound electronic modulation, generating highly electrophilic Mo 5.5 + centers and intermediate Ni 1.8+ valence states alongside abundant oxygen vacancies. Thus, the HE-MOF electrocatalyst greatly enhances lignin adsorption and deep oxidation, and accelerates interfacial electron transfer. Consequently, the designed LFFC with only 1 cm² active membrane achieves a record-high maximum power density of 545.48 mW cm⁻² at 90 °C, and generates 506.5 mW h of electricity with 1.0 g lignin, simultaneously powering a 1.5 V LED pattern and two windmill devices with only 1 cm² active membrane. This study provides atomic-level design strategy for high-entropy electrocatalysts to promote the application of advanced LFFC and industrial lignin. Download: Download high-res image (168KB) Download: Download full-size image