In recent years, with rapid spread of information-related equipment such as personal computers, video cameras, and mobile phones, batteries used as a power source therefor have been actively developed. Further, in the automobile industry, development of batteries having high output and high capacity for electric vehicles or hybrid vehicles has been promoted. Among various batteries, a lithium battery has an advantage of a high energy density.
In this regard, as a solvent of a liquid electrolyte for a lithium battery, it is known to use a glyme that is one of oligoethers. For example, Patent Literature 1 discloses a Li-based secondary battery which includes a cathode containing a specific electrode active material, a liquid electrolyte in which at least a part of a glyme and a Li salt forms a complex, and an anode. This technique is intended to improve rate characteristics and a power density of a battery. In addition, Patent Literature 2 discloses a liquid electrolyte which contains only a glyme as a solvent of the liquid electrolyte and an alkali metal salt as a solute of the liquid electrolyte, in which at least a part of the glyme and the alkali metal salt forms a complex. This technique is intended to provide a high-voltage liquid electrolyte having high thermal stability and being usable in general in-vehicle secondary batteries.