Degradation of magnesium-ion battery anodes by galvanic replacement reaction in all-phenyl complex electrolyte

•The spontaneous degradation of metallic Mg and Mg2Sn in APC has been studied using DFT calculation and experimental methods.•Mg atoms from metallic Mg and Mg2Sn are oxidized by the anions present in APC through galvanic replacement reaction.•APC-induced spontaneous degradation of Mg and Mg alloys is susceptible to affect the performance of Mg-ion battery anodes.