Dehydrogenation Performances of Different Al Source Composite Systems of 2LiBH4 + M (M = Al, LiAlH4, Li3AlH6).

Yun Li,Xuezhang Xiao,Jun He,Lixin Chen,Dongdong Zhu,Shaolong Wu

doi:10.3389/fchem.2020.00227

Abstract

Hydrogen has become a promising energy source due to its efficient and renewable properties. Although promising, hydrogen energy has not been in widespread use due to the lack of high-performance materials for hydrogen storage. Previous studies have shown that the addition of Al-based compounds to LiBH4 can create composites that have good properties for hydrogen storage. In this work, the dehydrogenation performances of different composite systems of 2LiBH4+ M (M = Al, LiAlH4, Li3AlH6) were investigated. The results show that, under a ball to powder ratio of 25:1 and a rotation speed of 300 rpm, the optimum ball milling time is 50 h for synthesizing Li3AlH6 from LiH and LiAlH4. The three studied systems destabilized LiBH4 at relatively low temperatures, and the 2LiBH4-Li3AlH6 composite demonstrated excellent behavior. Based on the differential scanning calorimetry results, pure LiBH4 released hydrogen at 469°C. The dehydrogenation temperature of LiBH4 is 416°C for 2LiBH4-Li3AlH6 versus 435°C for 2LiBH4-LiAlH4 and 445°C for 2LiBH4-Al. The 2LiBH4-Li3AlH6, 2LiBH4-LiAlH4, and 2LiBH4-Al samples released 9.1, 8, and 5.7 wt.% of H2, respectively. Additionally, the 2LiBH4-Li3AlH6 composite released the 9.1 wt.% H2 within 150 min. An increase in the kinetics was achieved. From the results, it was concluded that 2LiBH4-Li3AlH6 exhibits the best dehydrogenation performance. Therefore, the 2LiBH4-Li3AlH6 composite is considered a promising hydrogen storage material.

Highlights

Hydrogen energy has become an ideal new energy resource due to its clean, efficient, and renewable properties (Schlapbach and Zuttel, 2001)
Many factors impede the commercial application of pure LiBH4, such as high dehydrogenation temperature, slow dehydrogenation rate, and poor cycle reversibility (Lodziana and Vegge, 2004)
15 g mixed powder of LiH and LiAlH4 was milled each time with a molar ratio of 2:1, a ball to powder ratio of 25:1, and a milling speed of 300 rpm

Summary

INTRODUCTION

Hydrogen energy has become an ideal new energy resource due to its clean, efficient, and renewable properties (Schlapbach and Zuttel, 2001). Many factors impede the commercial application of pure LiBH4, such as high dehydrogenation temperature, slow dehydrogenation rate, and poor cycle reversibility (Lodziana and Vegge, 2004) To solve these issues, researchers have concentrated on modifying LiBH4 (Vajo and Olson, 2007) through anion/cation substitution (Fang et al, 2011; Lombardo et al, 2019), catalytic modification (Kou et al, 2012; Huang et al, 2016; Zhai et al, 2016), the combined effect of composites (Vajo et al, 2010; Kou et al, 2012), and the application of the confinement effect of nano-materials (Vajo, 2011; Zhang et al., 2017). Al-based LiBH4 composite systems, 2LiBH4-Al, 2LiBH4-LiAlH4, and 2LiBH4-Li3AlH6 were prepared, and the hydrogen storage performance was investigated

MATERIALS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS

DATA AVAILABILITY STATEMENT