Effects of adding calcium to lithium on the discharge and hydrogen evolution of lithium anodes

The effects of the alkaline earth metal calcium on the electrochemical behavior of lithium anode in 4 mol L−1 LiOH and NaOH solutions were investigated via hydrogen collection, X-ray diffraction (XRD) and scanning electron microscope (SEM). It was found that adding minor calcium to lithium decreased the hydrogen evolution on the surface of lithium–calcium alloy in the alkaline electrolyte containing corrosion inhibitors. The SEM image and XRD analysis showed that calcium formed calcium hydride on the surface of lithium–calcium alloy anode. The hypothesis has been proposed that the hydrogen inhibition effect is caused by calcium hydride combined with LiOH and LiOH·H2O formed on the anode surface. The formation of calcium hydride and LiOH and LiOH·H2O reduced the porosity of the film and water penetration onto the active sites of the lithium–calcium alloy.