Reversible Hydrogen Storage Performance of 2LiBH₄-MgH₂ Enabled by Dual Metal Borides

Abstract

2LiBH4-MgH2 is a typical reactive hydride composite with a capacity of 11.5 wt % that has attracted intensive attention. Its practical application, however, is hindered by sluggish kinetics, poor reversibility, and different reaction pathways under various temperatures and hydrogen back pressures. Herein, bimetallic (NiCo) sheet-like nanoporous carbon (NiCo@NC) is designed to improve the hydrogen storage performance of 2LiBH4-MgH2 composite. During the initial H2 desorption process of 2LiBH4-MgH2 under 4 atm H2 pressure, NiCo NPs in NiCo@NC would be in situ transformed into MgNi3B2, acting as the heterogeneous nucleation sites for MgB2, and CoB, serving as the effective catalyst for H2 desorption of 2LiBH4-MgH2 composite. Due to the synergistic effect of in situ formed CoB and MgNi3B2, the incubation period for 2LiBH4-MgH2 is reduced to 1.5 h in the initial H2 desorption process and almost vanished in the following H2 desorption and adsorption cycles, while the incubation time for bulk 2LiBH4-MgH2 composite reaches 16 h. More importantly, induced by the catalysis of NiCo@NC, 2LiBH4-MgH2 exhibits improved cycling stability with a reversible capacity of 8.4 wt % after 10 cycles of hydrogen storage process, corresponding to 95.5% of H2 desorption capacity of the second cycle. This work provides a potential strategy for the design of dual-functional catalysts to improve reversible hydrogen storage performance of reactive hydride composites.

Improvement in the Hydrogen Storage Properties of MgH2 by Adding NaAlH4

“…Complex hydrides such as LiBH 4 and NaAlH 4 have been studied by many researchers because they have high theoretical hydrogen storage capacities [1][2][3][4][5][6][7][8][9][10]. Many works were performed to improve the hydriding and dehydriding kinetics of Mg [11][12][13][14][15][16].…”

From Back to Stage: Superior Cycling Stability of 2LiBH4−MgH2 Enabled by Anion Tuning

“…[ 12 ] Nevertheless, none of these previous works claimed cycling stability exceeded 20 loops, [ 13 ] and meanwhile this metal‐cation tunning strategy has already approached its limit, even with exhausted multiphase or multiscale modulation. [ 5,11,13a,14 ] Therefore, it is urgent to propose a new perspective to further improve the hydrogen reaction kinetics and cycling stability of Li‐RHC.…”

Understanding and unlocking the role of V in boosting the reversible hydrogen storage performance of MgH2

“…1 Efficient and safe storage of hydrogen with high gravimetric and volumetric capacity poses a major bottleneck for the development of hydrogen energy. [2][3][4][5] Due to its high theoretical volumetric and gravimetric storage density (110 g L −1 and 7.6 wt%) and low price, magnesium hydride (MgH 2 ) is considered as one of the most ideal solid hydrogen storage materials. [6][7][8] Unfortunately, induced by the high thermodynamic stability and kinetic barrier, the operating temperature for the reversible hydrogen storage of MgH 2 is in general over 400 °C, which hinders its commercial applications for on-board hydrogen storage.…”