Molecular Engineering to Enable High-Voltage Lithium-Ion Battery: From Propylene Carbonate to Trifluoropropylene Carbonate
Jianzhong Yang, Qian Liu, Krzysztof Pupek, Trevor L. Dzwiniel, Nancy L. Dietz Rago, Jiayu Cao, Naveen K. Dandu, Larry A. Curtiss, Kewei Liu, Chen Liao, Zhengcheng Zhang
Abstract
Molecular engineering of electrolyte structures has led to the successful application of trifluoropropylene carbonate (TFPC), a fluorinated derivative of propylene carbonate (PC), in next-generation high-voltage high-energy lithium-ion cell. In contrast to a PC-based electrolyte which cointercalates in the form of Li+-solvated species into the graphene layer and exfoliates a graphite anode, a TFPC-based electrolyte is highly compatible with a graphite anode at low potential. Additionally, it shows exceptional oxidation stability on the charged cathode surface owing to the presence of the −CF3 group. An all-fluorinated electrolyte, that is, 1.0 M LiPF6 TFPC/2,2,2-trifluoroethyl carbonate (FEMC) (1/1 volume ratio) + FEC additive, was formulated and demonstrated excellent cycling stability in a high-voltage LiNi0.5Mn0.3Co0.2O2/graphite cell cycled between 3.0 and 4.6 V.