Optimizing the composition of LiFSI-based electrolytes by a method combining simplex with normalization

The optimizing method of electrolyte formulation is always vital for the development of high-performance lithium-ion batteries. Traditional optimization methods are mainly aimed at the optimization of the electrolyte composition type, and less attention is paid to the optimization of the composition proportion in a certain electrolyte formulation. In this paper, in order to balance the relationship between aluminum (Al) foil corrosion inhibition and battery electrochemical performance, the electrolyte system LiFSI 0.6 -LiBOB 0.4 -EC/DEC/EMC (1 : 1 : 1, by volume) was optimized by combining the simplex method, normalization and electrochemical testing. A lithium iron phosphate (LiFePO 4 ) cathode with the optimized electrolyte of LiFSI 0.53 -LiBOB 0.35 -EC/DEC/EMC (1.3 : 1.5 : 1.5) delivers a high capacity (143.1 mA h g −1 at 0.5C) and remarkable cycle life (94.9% retention after 100 cycles) at 45 °C. The outstanding performance is attributed to the composition of the cathode electrolyte interphase (CEI) containing the solid and dense LiF, AlF 3 , B 2 O 3 and Li 2 CO 3 . This provides a new method and idea for future electrolyte formulation optimization. The manuscript addresses that the electrolyte system with five components was optimized by combining the simplex method, normalization and electrochemical testing in lithium-ion batteries. The optimized electrolyte is better than commercial electrolyte LiPF 6 -EC/DEC.