| abstract |
(57) [Summary] An object of the present invention is to provide a lithium secondary battery excellent in battery capacity retention characteristics by suppressing manganese elution from lithium-manganese oxide. A mixed solution of lithium-manganese oxide having a spinel crystal structure composed of lithium and manganese, a positive electrode containing a conductive agent, a negative electrode, a main solvent composed of ethylene carbonate or propylene carbonate, and ethyl methyl carbonate is mixed. A non-aqueous electrolyte secondary battery containing an electrolytic solution in which lithium fluoroborate is dissolved, wherein the sum of the weight of manganese contained in the negative electrode and the electrolytic solution eluted from the lithium-manganese oxide in the positive electrode is equal to or less than that in the positive electrode. The non-aqueous electrolyte secondary battery is not more than 5% of the total weight of manganese contained in the non-aqueous electrolyte. |