Anode active material compsns anode sheet and Li ion cell

Abstract

The secondary battery of lithium ion includes positive pole, negative pole, electrolyte and diaphragm. The active material of positive pole is prepared by mixing spinel type lithium manganate and ternary positive materials of nickel, manganese and cobalt according to proportion 1-9: 9-1. Controlling mixing proportion and mean grain sizes of the said two substances controls orientation of spinel type lithium manganate on ternary positive materials as well as restrains Yang-Taylor effect of spinel type lithium manganate by ternary positive materials. The invention produces non-aqueous secondary battery of lithium ion with features of low cost, high capacity, good thermal stability, and good discharge performance of large current and small attenuation of capacity under high temperature.

Description

technical field [0001] The invention relates to an environment-friendly battery used in electrical appliances, in particular to a lithium-ion secondary battery, a positive electrode active material composition and a method for making the positive electrode sheet of the lithium-ion secondary battery. Background technique [0002] With the rapid development of the electronics industry and the information industry, people have higher and higher requirements for the power supply of various electrical products, among which lithium-ion secondary batteries are widely used due to their many superior properties. The positive electrode materials used in lithium-ion secondary batteries are mainly embedded compounds. At present, the main materials that can be used are ternary positive electrode materials, layered lithium cobalt oxide, and spinel lithium manganese oxide. The cathode material that has been widely used at present is layered lithium cobalt oxide material. [0003] Although...

AI Technical Summary

Problems solved by technology

[0006] In addition, because the volume of the unit cell of the spinel lithium manganese oxide material shrinks during charging, the volume expands during discharging, and overdischarge occurs easily in the surface area of ​​the positive electrode sheet during discharging, resulting in the Jahn-Teller effect. , to form a cubic crystal system with poor electrochemical performance, and this change is especially severe at high temperature, which becomes the main reason for the severe capacity fading of spinel lithium manganese oxide at high temperature. On the other hand, layered lithium cobalt oxide When charging, the unit cell expands, and when discharging, the unit cell shrinks, and because lithium cobalt oxide has a layered structure, the orientation is high, and it is easy to be parallel to the current collector, so that the permeability of the electrolyte is reduced, and in a large When the current is discharged, the number of lithium ions that can migrate decreases, resulting in a decrease in capacity