Lithium manganate battery

The invention relates to the technical field of manufacturing of lithium ion batteries, and particularly relates to a lithium manganate battery with relative high energy density and excellent storage performance, belonging to the field of electrochemistry. The lithium manganate battery is characterized in that a positive electrode material is prepared from the following components in percentage by mass: 96-98 percent of lithium manganate, 1-2 percent of alkaline substances and 1-2 percent of fluoride. According to the lithium manganate battery, due to fluoride and the alkaline substances in the positive electrode material, electrolyte decomposition and HF generation can be effectively inhibited, and dissolution of the positive electrode material Li2MnO4 can be reduced, so that the capacity recovery rate of the stored lithium manganate battery can be improved; and the charging specific capacity of a negative electrode material can be effectively improved by adding a silicon-carbon material into the negative electrode material, and the energy density of the lithium manganate battery can be further effectively increased.