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Free keywords:
complex hydrides, interface, Li-ion conductors, sodium ion conductors, solid-state electrolytes/ion conductors, X-ray Raman scattering, Alumina, Aluminum oxide, Hydrides, Interface states, Interfaces (materials), Lithium, Lithium compounds, Metal ions, Raman scattering, Silica, Sodium, Sodium Borohydride, Solid electrolytes, Complex hydrides, Electrolyte ion, Interface effect, Ion conductors, Li-ion conductor, Sodium ion conductors, Solid-state electrolyte, Solid-state electrolyte/ion conductor, X-ray raman scatterings, Nanocomposites
Abstract:
Solid-state electrolytes (SSEs) with high ionic conductivities are crucial for safer and high-capacity batteries. Interface effects in nanocomposites of SSEs and insulators can lead to profound increases in conductivity. Understanding the composition of the interface is crucial for tuning the conductivity of composite solid electrolytes. Herein, X-ray Raman Scattering (XRS) spectroscopy is used for the first time to unravel the nature of the interface effects responsible for conductivity enhancements in nanocomposites of complex hydride-based electrolytes (LiBH4, NaBH4, and NaNH2) and oxides. XRS probe of the Li, Na, and B local environments reveals that the interface consists of highly distorted/defected and structurally distinct phase(s) compared to the original compounds. Interestingly, nanocomposites with higher concentrations of the interface compounds exhibit higher conductivities. Clear differences are observed in the interface composition of SiO2- and Al2O3-based nanocomposites, attributed to differences in the reactivity of their surface groups. These results demonstrate that interfacial reactions play a dominant role in conductivity enhancement in composite solid electrolytes. This work showcases the potential of XRS in investigating interface interactions, providing valuable insights into the often complex ion conductor/insulator interfaces, especially for systems containing light elements such as Li, B, and Na present in most SSEs and batteries. © 2024 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH.
