History of Electrolyte Solution Development

The electrolyte for LIBs is a mixture of organic solvents and an electrolyte salt compoimd. The common solvents are a mixture of cyclic carbonate esters, such as ethylene carbonate and propylene carbonate, and linear carbonate esters, such as dimethyl carbonate and diethyl carbonate. The solution is completed with the addition of a salt compound such as LiPFe or LiBp4. Electrolyte solutions must enable the Li ions to transport freely, which requires both high dielectric constant and low viscosity. Cyclic carbonate esters have a high dielectric constant but high viscosity, while linear carbonate esters have low viscosity but low dielectric constant. Suitable electrolyte solutions are therefore obtained by mixing the two. 

FIGURE 1.10 Major materials in the LIB electrolyte salt market. 

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