Lithium Leaching–Induced Activation of Spent LFP Composites for Enhanced Water Oxidation with Concurrent Lithium Recovery

Abstract

We present a strategy for repurposing spent lithium iron phosphate cathodes into an efficient oxygen evolution reaction (OER) catalyst (s LFP@NiO). A key finding is that lithium leaching under OER conditions critically activates the catalyst. We show that leaching strengthens the Ni–Fe interface, promotes Fe enrichment in the surface layer, and expands the NiO lattice into an oxyhydroxide like structure that facilitates OH- diffusion. These changes drive surface reconstruction into an active γ-Ni(Fe)OOH phase and increase active site density, as confirmed by complementary structural analyses, leading to enhanced OER activity. Notably, chemical delithiation achieves identical activation, enabling simultaneous lithium recovery and catalyst production. This approach offers a dual function solution for sustainable water oxidation and battery waste valorization.