 We propose a new electrochemical system based on a negative electrode based on lithium pentatitanate, a positive electrode based on the lithium-vanadium(III) phosphate, 0.67 mol dm−3 lithium chlorate(VII) solution in a mixture of propylene carbonate and 1,2-dimethoxyethane as an electrolyte and consider the peculiarities of its functioning. The paper cites the arguments and experimental data disclosing the influence of the products of the secondary oxidation of 1,2-dimethoxyethane at the Li3V2(PO4)3-electrode on the functional behavior of the Li4Ti5O12-electrode as the main reason for the observed decrease in the characteristics of the battery prototypes and suggests the ways to solve this problem.