Wednesday, 12 October 2022: 14:20
Galleria 1 (The Hilton Atlanta)
High voltage aqueous Li-ion batteries have attracted great attention for large-scale energy storage due to their merits of intrinsic safety, low cost, and environmental friendliness. Despite recent developments such as “Water-in-salt” (WISE) electrolytes which extended the aqueous electrolyte stability window to 3.0 V and thus significantly enhanced the energy density of aqueous Li-ion batteries. Aqueous electrolyte beyond WISE with a lower salt concentration of <5.0 m and wider electrochemical stability window of >3.0 V is urgently needed to compete with commercial organic electrolytes. Here, we report a nonflammable ternary eutectic electrolyte that reduces the overall salt concentration to 4.5 m and expands the electrochemical stability window to >3.3 V by forming a robust solid electrolyte interphase (SEI). A remarkable performance of 500 cycles for practical LiMn2O4||Li4Ti5O12 pouch cells using a 4.5 m aqueous electrolyte was achieved. Critical factors including gravimetric energy density of LiMn2O4||Li4Ti5O12, self-discharge rate, and operation temperature range were investigated. This paper aims to show the possibility of the practical application of safe, low cost, and high energy aqueous Li-ion batteries.