Solid lithium hydride as a hydrogen source for fuel cells

Abstract

Hydrogen is produced by the hydrolysis reaction of solid lithium hydride and water. The hydrolysis reaction proceeds naturally with excess water. The reaction product, lithium hydroxide, is dissolved and removed from the reaction site by the excess water and steam. Two research test series conducted at the Naval Undersea Warfare Center are described. The first series were tests run at atmospheric pressure (0.1 MPa) in a transparent test fixture. The reaction was controllable. The reaction runs with seawater. The second series of tests were run at pressures from 0.25 to 1.50 MPa. The reaction runs at higher pressures with the hydrogen generation rate decreasing about one-third at 1.50 MPa. The water supply rate is the key determining factor. The surface area of solid lithium hydride plays only a minor role in determining the hydrogen generation rate. The process can be configured as a compact fuel source for multi-kilowatt, underwater propulsion systems.