Sustainable water oxidation enabled by a complex-doped cobalt oxide electrode

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Energy

Background:

• Cobalt-based electrocatalysts for water oxidation face stability challenges due to in-situ restructuring into disordered (oxy)hydroxides.
• This restructuring degrades structural integrity and electronic conductivity, limiting catalytic performance and lifespan.
• Developing stable and efficient electrocatalysts is crucial for sustainable water splitting technologies.

Purpose of the Study:

• To stabilize LiCoO2, a cobalt oxide derived from spent lithium-ion batteries, for enhanced water oxidation.
• To investigate the effect of complex doping with Ni, Fe, and Pd on the structural and electrochemical properties of LiCoO2.
• To improve the catalytic activity, stability, and mechanical robustness of cobalt-based electrocatalysts for water oxidation.

Main Methods:

• Co-doping LiCoO2 with varying concentrations of Ni, Fe, and Pd.
• Electrochemical characterization including water oxidation activity and stability tests.
• Membrane electrolyzer tests to evaluate performance against benchmark catalysts like RuO2.

Main Results:

• Co-doping LiCoO2 with Ni, Fe, and Pd mitigated in-situ spinel phase reconstruction and enhanced electrochemical stability.
• Optimized LiCo0.79Ni0.1Fe0.1Pd0.01O2 demonstrated over 2000 hours of water oxidation stability.
• In membrane electrolyzer tests, LiCo0.79Ni0.1Fe0.1Pd0.01O2 achieved 2.5 A cm-2 at 1.58 V with over 1400 hours of stability, outperforming RuO2.

Conclusions:

• Complex doping of LiCoO2 with Ni, Fe, and Pd is an effective strategy to enhance its stability and performance for sustainable water oxidation.
• The dopants improve conductivity, facilitate gas removal, and boost mechanical robustness, addressing key limitations of cobalt-based catalysts.
• This research provides valuable insights for designing robust and efficient electrocatalysts for water splitting, utilizing recycled battery materials.