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Achieving sustainable water oxidation presents significant challenges, particularly employing cobalt-based electrocatalysts. Despite promising activities, many cobalt-based electrocatalysts undergo in-situ partial restructuring into disordered (oxy)hydroxides, as indicated by the Pourbaix diagram. This restructuring typically degrades structural integrity and electronic conductivity, undermining catalytic stability. Here, we propose a complex doping strategy to stabilize LiCoO2, a cobalt oxide that can be sourced from spent lithium-ion batteries, for sustainable water oxidation. Specifically, by co-doping LiCoO2 with Ni, Fe, and Pd, we mitigate the reconstructed extent of the in-situ generated spinel phase during water oxidation reaction and enhance electrochemical stability. Furthermore, complex doping improves the surface conductivity and facilitates gas removal, boosting mechanical robustness. Consequently, the optimized LiCo0.79Ni0.1Fe0.1Pd0.01O2 achieves a competitive water oxidation stability of over 2000 hours. Additionally, in membrane electrolyzer tests, LiCo0.79Ni0.1Fe0.1Pd0.01O2 outperforms the benchmark RuO2, delivering 2.5 A cm-2 at 1.58 V and maintaining stability for over 1400 hours. By elucidating the role of each dopant in LiCo0.79Ni0.1Fe0.1Pd0.01O2, this work offers critical insights for the rational design of sustainable water splitting electrodes.
Wang et al. (Wed,) studied this question.