Disclosed are high enthalpy thermochemical energy storage materials that exhibit high thermal conductivity and stability at high temperature reaction conditions. Disclosed materials include hydride-based alloys that can undergo high temperature reversible hydrogenation/dehydrogenation reactions without phase change of any metal or metalloid components of the alloy. The materials undergo a reversible exothermic hydrogenation reaction to form a metal hydride and a ternary alloy that includes a high thermal conductivity metal that, in its pure state, would exhibit a phase change at the hydrogenation reaction conditions.