リチウムイオン電池廃棄物を原料とした海水電気分解用高耐久性酸素発生反応電極触媒

Electrocatalytic seawater splitting seems to be the most promising and urgent demand strategy for clean hydrogen energy production. Utilizing low-cost electrocatalysts is pivotal in the hydrogen economy, as seawater splitting can be made highly efficient and more economical. To meet these expectations, we proposed a novel utilization for the black carbon mass left over from hydrometallurgical metal recovery as an efficient and stable electrocatalyst for oxygen evolution reaction (OER) performed in alkaline media. The SEM-EDS, XPS, XRD, XRF, and Raman analyses revealed that the composition and structure of the post-leached battery powders depend on the hydrometallurgical waste recycling conditions, which in turn affect their OER electrocatalytic activity. In particular, the material leached with sulfuric acid (BAT 1) retained a higher content of cobalt-based compounds (mainly LiCoO₂ and Co₃O₄) embedded within a porous carbon matrix and, resulting in the best catalytic performance among all samples. The enhanced performance of BAT 1 is attributed to the synergy of its cobalt-based phases and the well-developed porous carbon structure, which collectively result in a high electrochemically active surface area. The electrochemical tests proved that Li-ion battery waste has remarkable OER catalytic performance with an overpotential of 226 mV and 225 mV, reaching 10 mA cm^- 2 in water splitting and in seawater splitting, respectively, which is only 14 mV and 95 mV higher than for benchmark RuO₂ in water splitting and seawater splitting, respectively.