Self-Discharge Decomposition of LiH Using a Metal–Insulator–Metal Diode

Bulk LiH is a thermally stable (decomposes up to 1200 K at 1 atm pressure) and electronically insulating (a wide bandgap of 4.9 eV) high-density energy compound. The self-discharge decomposition of bulk LiH was achieved both by the wired-up Pd/LiH/Al diode at 80 °C under vacuum and the wired-up Pd/LiH/Al diode assisted with DMSO at room temperature under vacuum. The LiH decomposition is rationalized as the thermally activated mobilities of Li⁺ and H⁻ or solvent-assisted ionic conductivities, which facilitate the pulling of H⁻ from LiH driven by the hydrogen affinity of palladium and the simultaneous flowing of electrons of H⁻ to Al for Li⁺ reduction through wired connection. The low temperature, especially room temperature, self-discharge decomposition of bulk LiH would be beneficial for high-purity lithium metal production and energy storage.