Intercalation of Li+ into a Co-Containing Steel-Ceramic Composite: Substantial Oxygen Evolution at Almost Zero Overpotential

Abstract

The exploration of promising renewable energy sources for the future is likely the most significant challenge for humanity. Hydrogen is considered to play a major role in the urgently required reorganization of our current energy sector. Water can be split into hydrogen and oxygen and therefore presents an in principle inexhaustible and environmentally friendly hydrogen source. However, electrochemical approaches for the cleavage of H2O remain challenging, especially considering that the experimentally required potential at which oxygen evolves is substantially higher than the theoretically required potential. This results in significant overpotentials (eta) on the anode side, which limits the widespread applicability of this technique. Here, we have applied a two-step activation procedure of a Co-containing steel, which led to a significant reduction of eta for the oxygen evolution reaction (OER) down to almost zero. The enhanced electrochemical behavior comes as a result of Li-ion doping, which leads to Li intercalation into the Co3O4 containing surface layer of the steel-ceramic composite material. Thus, our results indicate that additional metal doping and resulting surface modification is a promising strategy for achieving substantial OER at pH-neutral conditions close to the thermodynamic limit.