Novel Li3V2-xMox(PO4)3 Electrode Material and Liquid Electrolytes for Lithium-Ion Batteries Cycled at Cryogenic Temperatures

초록

Lithium-ion batteries (LIBs) are widely used owing to their high specific energy and long lifespans. However, cryogenic temperatures can restrict their application considerably-for example, during cold weather (winter) and military and aerospace exploration. Molybdenum (Mo)-doped Li3V2-xMox(PO4)(3) has a beneficial tetrahedron and octahedron structure that is stable at low temperatures and shorter distances (for Li+ transmission), which contributes to higher ion conductivity at low temperatures. The theoretical capacity of Li3V2(PO4)(3) in the 3.0-4.3 V working range is 132 mAh/g, reaching 197 mAh/g in the 3.0-4.8 V working range. In this study, we first examined the optimal molar ratio of Mo in a commercial electrolyte, the most suitable Mo molar ratio being 0.02 with a specific capacity of 121.3 mAh/g in the 3.0-4.3 V working range under ambient temperature conditions. Subsequently, we developed a novel electrolyte with a volume ratio of 1,3-dioxolane:1,2-dimethoxyethane (DOL:DME) of 8:2. Here, the specific capacity was 102.3 mAh/g at room temperature with a capacity retention of 42.3%; moreover, the specific capacity was 43.3 mAh/g at 223 K with a capacity retention of 0.11% at 193 K.

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