Corrosion of magnesium electrolytes: chlorides – the culprit

Chloride containing magnesium electrolytes are corrosive towards non noble metals. Currently the development of non-corrosive magnesium electrolytes is a key challenge on the road to a rechargeable magnesium battery. The component responsible for corrosion of magnesium electrolytes has not been previously elucidated. Here we clarify that chlorides in the cation (Mg2(μ-Cl)3·6THF)+ are a major culprit for corrosion. We also corroborate the feasibility of ion exchange reactions as a suitable synthetic approach towards magnesium electrolytes which do not contain the cation (Mg2(μ-Cl)3·6THF)+. Our results indicate that magnesium organoborates are an interesting class of magnesium electrolytes which undergo magnesium deposition and dissolution and are non-corrosive in nature at high voltages.