Importantly, Mg(BH 4 )(NH 2 ) was the first magnesium ion conductor where Mg stripping and plating behavior were confirmed. Building on this breakthrough, subsequent investigations explored the electrochemical properties of all-solid-state batteries utilizing Mg(BH 4 )(NH 2 ) as a solid electrolyte, sulfide-based positive electrode materials, and metallic magnesium negative electrodes, revealing promising initial discharge behavior.