Designing new functional materials is crucial for the development of efficient energy storage and conversion devices such as all solid-state batteries.
LiBH 4 is a promising solid electrolyte for Li-ion batteries. It displays high
lithium mobility, although only above 110 °C at which a transition to a high
temperature hexagonal structure occurs. Herein, it is shown that confining
LiBH4 in the pores of ordered mesoporous silica scaffolds leads to high Li+
conductivity (0.1 mS cm−1 ) at room temperature. This is a surprisingly high
value, especially given that the nanocomposites comprise 42 vol% of SiO2.
Solid state 7Li NMR
confirmed that the high conductivity can be attributed to
a very high Li+ mobility in the solid phase at room temperature. Confinement
of LiBH4 in the pores leads also to a lower solid-solid phase transition temperature
than for bulk LiBH4. However, the high ionic mobility is associated
with a fraction of the confined borohydride that shows no phase transition,
and most likely located close to the interface with the SiO2 pore walls. These
results point to a new strategy to design low-temperature ion conducting
solids for application in all solid-state lithium ion batteries, which could
enable safe use of Li-metal anodes.
, Nale, A., Sveinbjörnsson, D. Þ., Eggenhuisen, T. M., Verkuijlen, M. H. W., Suwarno, D., Vegge, T.
, Kentgens, A. P. M., & Jongh, P. E. D. (2015). Nanoconfined LiBH4 as a Fast Lithium Ion Conductor
. Advanced Functional Materials
(2), 184–192. https://doi.org/10.1002/adfm.201402538