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Solar-Driven Reversible Hydrogen Storage Over LiNH2-2LiH
Zibo Cheng1,2, Yeqin Guan1,3, Le Xie1
1Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China.
Angewandte Chemie (International Ed. in English)
|July 15, 2026
Summary
This study shows that UV light can break down lithium amide-lithium hydride composites for hydrogen storage. This photo-induced method enables efficient hydrogen release under mild conditions, overcoming previous limitations.
Area of Science:
- Materials Science
- Chemistry
- Energy Storage
Background:
- Lithium amide-lithium hydride composite (LiNH2-2LiH) is a promising material for hydrogen storage due to its high capacity (10.29 wt.%).
- Its practical application is limited by thermodynamic stability and slow reaction kinetics for N-H and Li-H bond cleavage and formation during hydrogen release and uptake.
- Current methods rely on high temperatures, hindering efficient hydrogen storage.
Purpose of the Study:
- To investigate the photo-induced destabilization of LiNH2-2LiH for efficient hydrogen storage.
- To explore the mechanism of UV-induced N-H bond cleavage and hydrogen evolution.
- To demonstrate the feasibility of hydrogen release and uptake under mild conditions using light.
Main Methods:
- Photoexcitation of LiNH2 using UV illumination (0.8 W·cm-2) to induce N-H bond cleavage.
- Coupling LiNH2 with LiH to suppress gaseous byproducts during UV-driven hydrogen release.
- Utilizing high-intensity full-spectrum illumination (2.9 W·cm-2) to leverage combined non-thermal and photothermal effects.
- Testing hydrogen release and uptake reversibility over multiple cycles.
Main Results:
- UV illumination of LiNH2 induced homolytic N-H bond cleavage, leading to H2, N2, and NH3 evolution.
- Coupling LiNH2 with LiH effectively suppressed gaseous byproducts during UV-driven hydrogen release.
- Complete dehydrogenation (>10.0 wt.%) of LiNH2-2LiH was achieved under high-intensity illumination.
- Near-full reversibility (ca. 99% capacity retention) was observed over 6 cycles.
- Direct hydrogen release from LiNH2-2LiH was demonstrated under natural sunlight.
Conclusions:
- Photo-induced destabilization is a viable strategy for activating strong bonds in amide-hydride composites.
- This approach offers a promising pathway for solid-state hydrogen storage under mild conditions.
- The developed method overcomes the kinetic and thermodynamic limitations of traditional thermal dehydrogenation.
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