Preparation and properties of Mg-doped Li-B alloy anode materials for high specific-capacity thermal batteries

•We provide an alternative to the conventional Li-B alloy for thermal battery.•The Mg-doped Li-B alloy anode was prepared by high-temperature melting process.•The specific capacity of novel Mg-doped Li-B alloy is up to 4270 As/g.•The Li loading in novel Li-B anode is up to 64% and free Li is more than 40%.