Bioinspired value-added conversion of rotten bread into porous vanadium oxide-vanadium carbide@carbon composites for high-rate Zn- and Li-ion batteries

Abstract

The rapid accumulation of food waste has emerged as a pressing environmental challenge, motivating the development of sustainable strategies for waste valorization. Developing sustainable routes to transform discarded food-waste into functional electrode materials offers an effective solution to these challenges while supporting the growing demand for advanced battery technologies. In this work, we report a simple, scalable, and cost-effective approach to convert rotten bread into a highly porous vanadium oxide-vanadium carbide/carbon (VO-VC) composite through an infiltration and in-situ thermal process. Unlike conventional multistep routes that rely on post-synthetic carbon coating, our method enables the simultaneous formation of a conductive carbon framework and electroactive vanadium-based VO-VC heterostructures, which ensures intimate interfacial contact and enhanced electrochemical kinetics. In particular, the synergistic integration of VO and VC on porous carbon generates abundant heterointerfaces, enables lower charge transfer resistance and higher diffusion coefficients (σ = 6.47×10-13 cm2 s-1) during the Li-ion energy storage. As a result, the optimized VO-VC@800 electrode exhibits excellent electrochemical performance when evaluated as a Li-ion battery anode, delivering a high reversible capacity of 759.2 mAh g-1 at 0.1 A g-1 with a good rate capability of 407.8 mAh g-1 at 1 A g-1, and long-term cycling stability (9.5% capacity loss) after 100 cycles and the electrode still showed good cycling stability after 450 cycles. Moreover, the same electrode demonstrates robust performance in aqueous zinc-ion batteries, achieving a high specific capacity of 170 mAh g-1 along with stable cycling and good rate characteristics, benefiting from rapid Zn2+ transport and structural integrity. Overall, our work demonstrates a viable waste-to-watts materials strategy and highlights the potential of biomass-derived metal oxide-carbon composites for sustainable rechargeable battery applications.