Pyrolysis-gas reduction and carbonated water leaching for recycling spent LiCoO2 battery black mass

Spent LIB black mass is a highly heterogeneous mixture, and its compositional complexity remains a key barrier to efficient and sustainable circularity of energy materials. Here, we propose an enhanced gas-phase recovery route integrating pyrolysis-gas reduction with CO 2 -carbonated water leaching for LiCoO 2 black-mass recycling. Biomass-derived reducing gases, together with intrinsic graphite, cooperatively tune the reducing atmosphere, oxygen potential, and phase evolution, while graphite acts as an in situ carbon source to drive secondary gas equilibria and gas-solid reactions, reshaping the CO/CO 2 /H 2 /CH 4 composition and stabilizing Li as Li 2 CO 3 . Downstream, CO 2 -carbonated water enables selective Li dissolution via a reversible bicarbonate pathway, lowering water use and evaporation energy demand. An integrated electrochemical purification step rapidly removes trace dissolved Co from the carbonate leachate, supporting closed-loop operation and product purity. Validated using real smartphone black mass, the process delivers high recoveries (∼97%) of Li and Co as Li 2 CO 3 and Co 3 O 4 for LiCoO 2 batteries. This work offers energy-relevant insights for building low-energy, low-waste recycling pathways that improve material security and economic resilience. An integrated pyrolysis-gas reduction and CO 2 -carbonated water leaching strategy enables low-temperature, low-water recycling of spent LiCoO 2 black mass, achieving selective Li recovery and cleaner separation of Co-containing products. Download: Download high-res image (202KB) Download: Download full-size image