Deforming lanthanum trihydride for superionic conduction.

With strong reducibility and high redox potential, the hydride ion (H-) is a reactive hydrogen species and an energy carrier. Materials that conduct pure H- at ambient conditions will be enablers of advanced clean energy storage and electrochemical conversion technologies1,2. However, rare earth trihydrides, known for fast H migration, also exhibit detrimental electronic conductivity3-5. Here we show that by creating nanosized grains and defects in the lattice, the electronic conductivity of LaHx can be suppressed by more than five orders of magnitude. This transforms LaHx to a superionic conductor at -40 °C with a record high H- conductivity of 1.0 × 10-2 S cm-1 and a low diffusion barrier of 0.12 eV. A room-temperature all-solid-state hydride cell is demonstrated.

Catalyst-free synthesis of lithium hydride at room temperature.

An organic solvent-assisted catalyst-free mechanochemical reaction is developed to synthesize lithium hydride at mild gas pressures and room temperature. Studies show that the formation of intermediates on the surface of bulk lithium metal is crucial for the synthesis of high purity (>98%) LiH. This provides a new strategy for the large-scale production of lithium-based hydrogen storage materials.