The critical role of H reduction roasting for enhancing the recycling of spent Li-ion battery cathodes in the subsequent neutral water electrolysis

• Published in: RSC sustainability Vol. 1; no. 9; pp. 2241 - 2253
• Main Authors: Zhou, Jiayin, Ni, Jihong, Guan, Xiaofei
• Format: Journal Article
• Published: 30.11.2023
• ISSN: 2753-8125
• DOI: 10.1039/d3su00201b

Effective and sustainable recycling of lithium-ion batteries is critically important for comprehensive resource utilization and environmental protection. Herein, we propose a novel recycling process that combines H 2 reduction roasting and neutral water electrolysis to recover valuable metal elements from the waste cathodes of spent lithium-ion batteries. Firstly, the waste cathode materials were calcined in H 2 to form oxides with lower valence transition metal ions. Then, the low-valence transition metal ions were leached from the reduced materials in the low-pH chamber and precipitated as hydroxides in the high-pH chamber of the neutral water electrolyzer. Three common LIB cathodes ( i.e. , LiCoO 2 , LiMn 2 O 4 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 ) were processed with this new combined method, and the leaching efficiencies of the Li ion and the transition metal ions significantly improved versus not using the reductive H 2 roasting. The leaching kinetics of LiCoO 2 , LiMn 2 O 4 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , CoO, MnO, and NiO were carefully analyzed and compared to further understand the advantages of the combined method. The kinetics study supports the experimental finding that the transition metal elements are more easily leached from the roasted products than from the pristine cathode materials. Moreover, the H 2 produced at the cathode chamber of the neutral water electrolyzer can be recycled to the first step of reduction roasting, realizing the closed-loop utilization of H 2 . This work highlights the critical role of H 2 reduction roasting in improving the recycling of the waste cathodes in the subsequent neutral water electrolysis. This work reports a novel process that combines H 2 reduction roasting and neutral water electrolysis for recycling valuable metal elements from the waste cathode of spent Li-ion batteries.