Recycling Defunct Lithium-Ion Battery Cathodes to Quaternary Layered Double Hydroxides for Efficient Oxygen Evolution Reaction.

With the wide-application of batteries (LIBs) correlated industries, continuous accumulation of wasted LIBs occurs, which causes environment issues and exhaustion of metal resources. Therefore, it is of vital importance to develop practical and efficient techniques to reuse the materials in wasted LIBs. In this work, a novel approach is proposed to reuse scrapped Li(CoNiMn)O and LiFePO cathodes by converting them into oxygen evolution reaction (OER) electrocatalysts through simple leaching and co-precipitation steps. The synthesized quaternary layered double hydroxides (Q-LDHs) exhibits excellent OER activity, with the optimized Q-LDH-0.1 requiring a low overpotential of 270 mV to achieve the given current density of 10 mA cm, showing a low Tafel slope of 66 mV dec. The high catalytic activity of Q-LDH-0.1 should be attributed to the synergistic effects of electron interactions among homogeneously distributed iron, nickel, cobalt, and manganese atoms, the highly disordered coordination environment, and the catalytic activity of their mixed valence states, which combine to enhance the adsorption and transformation of OER intermediates. Additionally, the involvement of the more favorable lattice oxygen mechanism further promotes OER efficiency. This work presents a feasible approach for recycling abandoned LIB cathodic materials and offers valuable insights for developing low-cost, highly-effective LDH electrocatalysts.