Remarkable hydrogen storage properties at low temperature of Mg-Ni composites prepared by hydriding combustion synthesis and mechanical millingElectronic supplementary information (ESI) available. See DOI: 10.1039/c5ra09754a

• Main Authors: Tan, Yajun, Mao, Qifeng, Su, Wei, Zhu, Yunfeng, Li, Liquan
• Format: Journal Article
• Language: English
• Published: 22.07.2015
• ISSN: 2046-2069
• DOI: 10.1039/c5ra09754a

Mg 100− x Ni x ( x = 0, 5, 10 and 20) composites with the main particle size below 400 nm were synthesized by hydriding combustion synthesis followed by mechanical milling (HCS + MM). XRD and TEM results of Mg 100− x Ni x revealed that the products had the phases of MgH 2 , Mg 2 NiH 4 , Mg 2 NiH 0.3 and Mg (Mg just for x = 0 and 5), with Mg-Ni hydrides distributing uniformly in the composites. DSC results of Mg 100− x Ni x composites demonstrated that the hydrogen desorption peak for MgH 2 in the Mg 80 Ni 20 composite was decreased to 223.9/247.3 °C. With 5 at% Ni added, the Mg 95 Ni 5 reached its saturated hydrogen absorption capacity of 5.80 wt% within 100 s at 473 K. As for Mg 80 Ni 20 , a hydrogen absorption of 3.70 wt% at 313 K and a desorption capacity of 1.84 wt% at 473 K could be obtained. The Mg 2 Ni distributing uniformly in Mg-Ni composites significantly facilitates hydrogen diffusion and improves the hydriding/dehydriding kinetics and hydrogen storage capacity at low temperature. The amount of Ni is related greatly to the hydriding/dehydriding properties of Mg 100− x Ni x , which makes the hydrogen storage capacity and hydriding/dehydriding kinetics remarkable. Besides, the excellent cycling stability was also obtained through the isothermal de/hydrogenation cycling kinetics measurement. Mg 100− x Ni x ( x = 0, 5, 10 and 20) composites with excellent hydrogen storage properties at low temperature are synthesized by HCS + MM.