Spent electrode co-upcycling empowers anode-free Zn - I₂ batteries

With a growing amount of spent lithium-ion batteries estimated to accumulate over years, developing efficient recycling methodologies becomes urgent. Despite many efforts in this direction, the current routes require costly procedures with limited efficiencies and give rise to the under-utilization of recovered materials over both electrodes. Here, we put forward a co-upcycling strategy by integrating hydrometallurgy with Joule heating to address these concerns. Inspired by the Zn - iodine battery research community, we fully utilize the regenerated anode and cathode species from SLIBs into constructing prototype Zn - I₂ battery affording dual-electrode regulation. Operando spectroscopic characterizations and theoretical simulations reveal the co-upcycled materials simultaneously help mitigate polyiodide shuttle effect and ameliorate Zn deposition reversibility. Leveraging this strategy, the thus-derived anode-free Zn - I₂ pouch cell demonstrates an energy density of 229 Wh kg^-1. Techno-economic analysis further suggests the material usage and energy consumption in our protocol are notably low. This work is anticipated to establish an innovative paradigm of environmentally sustainable solutions toward next-generation energy storage.