HSAB theory predicts the design of sulfide-based solid electrolytes with excellent air-stability and high ionic conductivity.
A substituted Li4SnS4 solid electrolyte has been designed and demonstrated to have excellent air stability and exceptionally high ionic conductivity. This discovery opens the possibility for the design of new batteries that are safer and have higher energy density than today’s batteries. Hard and soft acid base (HSAB) theory was used to design sulfide-based solid electrolytes via aliovalent substitution of Li4SnS4 to achieve high conduction and excellent air stability. The optimized composition of Li3.833Sn0.833As0.166S4 has a high ionic conductivity of 1.39 mScm-1 at 25°C and a low activation energy of 0.21 eV. When evaluated in test cells, this electrolyte was found to be suitable for over a broad temperature range with stable performance. As part of this study, a new coating approach was developed to prevent interfacial reactions between solid electrolytes and metallic lithium. These findings provide key insights for the design of new solid electrolytes that will enable the development of safe, high energy batteries.
Gayatri Sahu, Zhan Lin, Juchuan Li, Zengcai Liu, Nancy Dudney, and Chengdu Liang, “Air-Stable, High-Conduction Solid Electrolytes of Arsenic-Substituted Li4SnS4,” Energy & Environmental Science, DOI: 10.1039/c3ee43357A
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