Recovery valuable metals from spent lithium-ion batteries via a low-temperature roasting approach: Thermodynamics and conversion mechanism

As the pressure on resources and the environment from spent lithium-ion batteries (LIBs) continues to grow, an efficient and low-cost method of the recycling process is necessary for battery sustainability. Here, we exhibit a low-temperature and acid-free leaching method based on intermediate-products extracting to recycle spent LiNi_1/3Co_1/3Mn_1/3O₂ (NCM111). Different from the conventional salt-assisted roasting process generating sulfates and metallic oxides, the roasted products of metal-ammine-sulfate complex salts were obtained at optimal conditions. Specifically, the pivotal reaction parameters, such as roasting temperature, time, mass ratio, were systematically investigated. After roasting with (NH₄)₂SO₄ at 400 °C for 20 min, more than 98% Li and 96% of Ni, Co, and Mn were leached by water at room temperature. Additionally, thermodynamic, macro-micro scale, kinetic, and economic evaluation of the recycling process were investigated, and a plausible reaction mechanism was proposed. At last, an economic and environmental benefits recycling process was presented, which is prospective for future industrial recycling of spent LIBs.