Bioinspired Ultrafast All-Climate Self-Charging Flow Battery

Self-charging batteries represent a promising type of energy system for round-the-clock energy supply and delivery. Current state-of-the-art implementations predominantly employ solid-state electrodes that exploit spontaneous reactions between discharged catholytes and oxygen from the air. However, the inherent sluggish heterogeneous solid-gas interfacial reactions impose severe thermodynamic and kinetic constraints, limiting charging rates to hours. Inspired by nature's rapid flavin-based extracellular electron-transfer mechanism, we developed an ultrafast all-climate self-charging battery based on flavin redox chemistry. Capitalizing on flavin's fast reaction kinetics in liquid phases to break the bottleneck of solid-state reactions, the assembled self-charging flow battery demonstrates a record-high charging rate, with 90% of capacity achieved within 10 min. In situ/ex situ characterizations revealed that the enthalpically favorable inner-sphere electron transfer involving flavin's isoalloxazine ring drives the ultrafast kinetics. By tailoring the solvation environment of the electrolyte via additive engineering, all-climate operations of the battery were achieved, demonstrating decent cycling stability in a wide temperature range between -20 and 50 °C. By mimicking the ubiquitous metabolic processes in nature, this as-fabricated ultrafast all-climate self-charging flow battery broadens the design of sustainable and green energy systems operating in harsh environments.