The Superiority of Asymmetric Alkyl Methyl Carbonates as Solvents for Li-ion Battery Electrolytes

摘要

The electrochemical behavior of graphite electrodes cycled galvanostatically vs. Li metal in electrolyte solutiosn containing LiPF_6, LiC(SO_2CF_3)_3 and LiN(SO_2C_2F_5)_2 in ethyl and methyl alkyl carbonates was studied. The solvents include ethyl methyl, ethyl propyl, methyl propyl, isopropyl methyl and isorpopyl ethyl carbonates. The use of asymmetric, aliphatic alkyl methy carbonates is shown to be essential to achieve both high capacity and long cycle life with graphite electrodes in Li-ion batteries.