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

Li-doped Co3O4 (LixCo3−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 LixCo3−xO4 samples were formed as tetragonal powders with a simple spinel structure and with particle sizes about 30–40 nm. All LixCo3−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. Li0.21Co2.79O4 exhibited the highest OER activity amongst the five samples. A single cell, non-precious metal alkaline anion exchange membrane water electrolysers (AAEMWE) with Li0.21Co2.79O4 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.

► Li-doped Co3O4 nanopowders (30–40 nm) were prepared with various Li contents. ► Li doping improved conductivity and OER activity of the cobalt oxide. ► MEA with LixCo3−xO4 exhibited 300 mA cm−2 with voltage 2.2–2.05 V at 20–45 °C. ► Degradation mechanism shall be studied to improve stability of the performance.