A Li-doped Co3O4 oxygen evolution catalyst for non-precious metal alkaline anion exchange membrane water electrolysers

Li-doped Co₃O₄ (Li_xCo_3−xO₄, x = 0, 0.07, 0.21, 0.35, 0.49) spinel powders were prepared with a thermal decomposition method and characterized by XRD, SEM, TEM, and XPS. The Li_xCo_3−xO₄ samples were formed as tetragonal powders with a simple spinel structure and with particle sizes about 30–40 nm. All Li_xCo_3−xO₄ samples exhibited a 50 mV more negative onset potential for oxygen evolution reaction (OER) than Co₃O₄. The influence of Li-doping is discussed regarding cation distribution, electronic conductivity and oxygen binding energy. Li_0.21Co_2.79O₄ exhibited the highest OER activity amongst the five samples. A single cell, non-precious metal alkaline anion exchange membrane water electrolysers (AAEMWE) with Li_0.21Co_2.79O₄ anode exhibited a current density of 300 mA cm⁻² at a voltage 2.2 to 2.05 V at temperatures of 20–45 °C and the stability was examined with a continuous operation for 10 h at 300 mA cm⁻² and at 30 °C.