Synergistic Charge Scavenging in Pt/C‐Polyoxometalate Systems for Scalable Biomass Power Generation via Super‐Reduced Electrolytes

Direct electrochemical conversion of unrefined biomass waste into electricity offers a sustainable pathway for decentralized energy generation, yet its practical implementation has been fundamentally hindered by low power densities and limited scalability. A fundamental bottleneck lies in the intrinsic recalcitrance of biomass, which restricts electron harvesting to shallow oxidation pathways and confines redox mediators to low reduction states. Here, we demonstrate a scalable biomass flow fuel cell (BFFC) enabled by a super‐reduced polyoxometalate (POM) electrolyte that overcomes the long‐standing electron‐harvesting ceiling. By employing a catalytic oxidative degradation strategy that promotes extensive cleavage of recalcitrant C─C linkages in the lignocellulosic matrix, we unlock deep multi‐electron reduction of POM, achieving an electron transfer capacity exceeding four electrons per molecule. As a result, the single‐cell device delivers a record‐breaking power density of 218.6 mW cm − 2 . Beyond laboratory‐scale demonstrations, we constructed a 10‐cell stack prototype, producing 59.2 Wh over 15.6 h of stable operation directly from raw biomass.