Abstract We have been studying a cell system which consists of an amorphous (a-) V 2O 5-P 2O 5 (95:5 in molar ratio) cathode, a lithium (Li) metal anode and an organic electrolyte by fabricating an AA-size prototype cell. In a previous study, we reported the influence of the mixing ratio of ethylene carbonate (EC) and propylene carbonate (PC) solvents, in EC/PC binary mixed solvent systems incorporating LiAsF 6 as the solute, on the cell performance and safety of Li/a-V 2O 5-P 2O 5 cells. In this paper, we examine the influence of LiAsF 6-EC/PC/2-methyl-tetrahydrofuran (2MeTHF) (solvent mixing volume ratio; 15:70:15) ternary mixed solvent electrolyte on the properties of AA-size Li/a-V 2O 5-P 2O 5 cells. The goals are to improve the cycle life of Li/a-V 2O 5-P 2O 5 cells while ensuring their safety and controlling their cost. Cell performance includes rate capability and charge-discharge cycle life. The abuse tests carried out on the Li/a-V 2O 5-P 2O 5 cells consist of a heating test at 130 °C and an external short circuit test at 25 °C. Cells with a ternary mixed solvent electrolyte have a longer cycle life than cells with EC/PC binary mixed solvent electrolytes. In addition, these cells are much less likely to suffer from soft shorting at low discharge rate cycles than cells with EC/PC binary mixed solvent electrolytes. This improvement in the cycle life is thought to result from an improvement in the Li anode cycling efficiency based on Li-half cell cycling test results. In addition, the abuse tests ensure the fundamental safety of cells containing ternary mixed solvent electrolyte.