Investigating The Cycling Performance of Lithium Hydride-Porous Silicon Alloys for Solid-State Hydrogen Energy Storage

Abstract

Among light metals, lithium hydride (LiH) offers a high hydrogen storage capacity (~12.6 wt.%); however, it faces chal-lenges like high thermodynamic stability (~700 °C required for decomposition) and reactivity with moisture, leading to lithium oxide and hydroxide formation. This study explores improving the thermodynamic properties of LiH and cyclic stability by alloying it with porous silicon (PS), a nanostructured material synthesized via electrochemical anodization. The LiH-PS alloy was prepared using high-energy milling and heat treatment at 500 °C for 3 hours. Hydrogen uptake was measured through kinetic analysis and pressure composition isotherms (PCI) at 400 °C and ~3.8 MPa. During 10 hydro-genation cycles, the alloy exhibited an initial absorption of ~4.2 wt.% in 6 minutes, stabilizing at ~2.5 wt.% over 3 hours in subsequent cycles. A slight capacity decrease (0.11 wt.%) after 10 cycles confirmed its stability for repeated use.