A room temperature rechargeable all-solid-state hydride ion battery

As a negative charge carrier, the hydride ion (H^-) is more energetic, polarizable and reactive than cations¹. An H^--mediated electrochemical process is fundamentally different from existing systems and enables the development of innovative electrochemical devices, such as rechargeable batteries, fuel cells, electrolysis cells and gas separation membranes². Here we developed a core-shell hydride 3CeH₃@BaH₂, which exhibits fast H^- conduction at ambient temperature and becomes a superionic conductor above 60 °C. This hydride allows us to construct an all-solid-state rechargeable H^- battery CeH₂|3CeH₃@BaH₂|NaAlH₄, which operates at ambient conditions using NaAlH₄ and CeH₂ as cathode and anode materials, respectively. This battery has an initial specific capacity of 984 mAh g^-1 and retains 402 mAh g^-1 after 20 cycles. Using hydrogen as charge carriers can avoid the formation of detrimental metal dendrites, in principle, which creates new research avenues for clean energy storage and conversion.