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

- Mica glass ceramic was used for storing hydrogen for the first time.
- Spodumene, Na-fluorophlogopite, Na-mica, forsterite and Lucite were obtained.
- Hydrogen uptake reaches 1.25, 2.5 and 1.9 wt% for GLi, GNa, and GK respectively.
- Hydrogen was adsorbed in the molecular form.
- Na-bearing sample with sheet structure is the proper samples for hydrogen storage.

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.