Reaction at the positive electrode on Al foil of lithium-ion batteries in alkaline water and related reactions in the coexistence of halide ions

Lithium-ion batteries have a significant safety risk of extensive fire and explosion accidents due to thermal runaway. One of the key issues of the recycling of end-of-life lithium-ion batteries is safe deactivation prior to the separation and recovery of the elements. This study aimed to improve the safety in the deactivation process of wastes of lithium-ion batteries by crushing in lime water under an inert atmosphere by investigating the reaction at the positive electrode. Especially, the solution conditions to generate O 2 gas at the positive electrode were investigated to avoid hydrogen explosion caused by H 2 gas generated at the negative electrode. The positive electrode retrieved from lithium-ion batteries was solely immersed in Li salt-added solutions. The generated gas was analysed by gas chromatography, and the shift of immersion potential was measured. The generation of O 2 gas was accelerated and suppressed by the existence of Li + cation and halide anions, respectively. The gas species was consistent with the immersion potential of the positive electrode. The behavior of waste of lithium-ion batteries during the deactivation by immersion in salt water is discussed. In addition, several reductants were added to the solution to utilize the function of sacrificial anode.