Preparation and characterization of mica glass-ceramics as hydrogen storage materials

This work is an attempt to study storing hydrogen in safe, reliable, compact, and cost-effective glass-ceramics materials for the first time. The effect of replacing K⁺ by Na⁺ or Li⁺ in the fluorophlogopite formula KMg₃AlSi₃O₁₀F₂ was studied using DTA, XRD and SEM. Also the effect of the crystallized phases within glass-ceramics on the surface area and capacity of storing hydrogen under different pressures were studied. Replacement of K⁺ by Na⁺ or Li⁺ leads to increase the temperature of crystallization in the same order. XRD revealed crystallization of spodumene (LiAlSi₂O₆) and forsterite (Mg₂SiO₄) in GLi and Na-fluorophlogopite (NaMg₃AlSi₃O₁₀F₂) and Na-mica (NaAl₃Si₃O₁₁) in GNa while Lucite (KAlSi₂O₆) and forsterite in GK. Surface area measurements for optimum samples showed low values in the range 0.48–0.58 m²/g; also total pore volumes have low values 9.4 × 10^?4–6.99 × 10^?3 cm³/g. The hydrogen adsorption content reached 1.25, 2.5, 1.34 sand 1.9 wt% for GLi, GNa, GK and GK samples heated for 2 h at 770,1100, 1000 and 1100 °C, respectively. The results obtained that, Na-bearing samples are the proper for hydrogen storage wherein sodium mica and phlogopite with characteristic sheet structure were crystallized.