Reversing the Irreversible: Thermodynamic Stabilization of LiAlH4 Nanoconfined Within a Nitrogen-Doped Carbon Host
- Sandia National Lab. (SNL-CA), Livermore, CA (United States); Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sandia National Lab. (SNL-CA), Livermore, CA (United States)
- SLAC National Accelerator Lab., Menlo Park, CA (United States)
- Inst. for Basic Science, Seoul (Korea, Republic of); Seoul National Univ. (Korea, Republic of)
- Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of)
A general problem when designing functional nanomaterials for energy storage is the lack of control over the stability and reactivity of metastable phases. Using the high-capacity hydrogen storage candidate LiAlH4 as an exemplar, we demonstrate an alternative approach to the thermodynamic stabilization of metastable metal hydrides by coordination to nitrogen binding sites within the nanopores of N-doped CMK-3 carbon (NCMK-3). The resulting LiAlH4@NCMK-3 material releases H2 at temperatures as low as 126 °C with full decomposition below 240 °C, bypassing the usual Li3AlH6 intermediate observed in bulk. Moreover, >80% of LiAlH4 can be regenerated under 100 MPa H2, a feat previously thought to be impossible. Nitrogen sites are critical to these improvements, as no reversibility is observed with undoped CMK-3. Density functional theory predicts a drastically reduced Al–H bond dissociation energy and supports the observed change in the reaction pathway. Finally, the calculations also provide a rationale for the solid-state reversibility, which derives from the combined effects of nanoconfinement, Li adatom formation, and charge redistribution between the metal hydride and the host.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS); Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- Ministry of Trade, Industry & Energy, Republic of Korea; USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- Grant/Contract Number:
- AC02-05CH11231; AC52-07NA27344; NA0003525
- OSTI ID:
- 1808761
- Report Number(s):
- LLNL-JRNL--820001; SAND2022-1884J; 1028406
- Journal Information:
- ACS Nano, Journal Name: ACS Nano Journal Issue: 6 Vol. 15; ISSN 1936-0851
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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analytical chemistry
coordination chemistry
hydrogen
hydrogen storage
inorganic chemistry
materials science
metal hydrides
metastable materials
nanoconfinement
nanoscience and nanotechnology
organic chemistry
physical chemistry
porous carbons
solid state physics