Fast-charging hybrid battery cathodes with internal redox mediation operable at 10C-rate

Structural batteries require electrodes with integrated energy storage with load-bearing properties. Active materials such as lithium iron phosphate (LFP) typically show high rate capabilities, but, when investigated in a structural battery platform, LFP exhibits poor rate capabilities. Organic radical polymers are promising alternatives because they possess fast-charging properties and good cycling stability. In the present work, we combine the redox-active polymer PTMA-GMA (poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate)- co -(glycidyl methacrylate)) with LFP on a carbon fiber (CF) weave as a structural support. Synergistic redox mediation between PTMA and LFP facilitates fast charging in the hybrid cathode up to 10C-rate in the structural battery platform. The PTMA-GMA/LFP CF hybrid structural cathodes exhibit a reversible capacity of 104 mAh g -1 at 1C-rate and a 30% capacity retention at 10C-rate. Further, during a fast C-rate charging and slow C-rate discharging protocol, the hybrid structural cathodes retained 50% of their initial capacity at 10C-rate. At the even higher C-rate of 25, the power was 2240 W kg -1 of combined active material. As compared to other structural battery cathodes, the power attained by this structural hybrid electrode is among the highest known and offers opportunities for mass savings in structural composites and energy storage devices. • Redox-active PTMA-GMA and LFP active materials coated on CF electrodes were prepared as structural composite hybrid cathodes and investigated in lithium metal half-cells. • The PTMA-GMA/LFP structural cathode achieved a high fast-charging rate capability (∼ 10 C-rate), demonstrating a 50% capacity retention at 10 C-rate. • The hybrid cathode exhibited a mediation facilitated by internal electron transfer between PTMA and LFP thus promoting fast-charging, • The obtained specific power is among some of the highest ever observed for structural electrodes