Alcohol-Based Electrolytes—An Alternative Between Aqueous and Nonaqueous for Increased Voltage and High-Rate Lithium-Ion Batteries

Currently, lithium-ions battery as the most important energy storage device has occupied most markets. High safety and high energy density batteries are still urgently required in our life. Some novel electrolyte matching high-voltage battery endurance has attracted much attention. Concentrated electrolytes thanks to their large electrochemical window, are promising electrolytes. We study here different concentrated solutions as electrolytes composed of LiTFSI salt and methanol solvent. Here a methanol-in-salt (MIS) electrolyte with 17 M LiTFSI in methanol is explored. As alcohol-based electrolyte with an alcohol solvation structure is formed, the 17 M electrolytes show better electrochemistry window which can reach a 3.13 volts potential platform and the maximum voltage can reach to 5.23 volts. The LiFePO₄/active carbon and Li₄Ti₅O₁₂/active carbon cells can cycle stably using the 17 M electrolytes. Furthermore, some high-voltage cell of LiMn₂O₄, Li_1.03(Ni_0.5Co_0.2Mn_0.3)_0.97O₂ still can work with the MIS electrolytes. A full cell using LiFePO₄/Li₄Ti₅O₁₂ can cycle more than 100 cycles with the 17 M electrolyte at a high-rate current. It shed a light that the nontoxic and environmental alcohol-based electrolytes can be used in high-rate batteries in the future.