Lithium cell plus plate and its preparation method and lithium ion secondary battery

Abstract

This invention discloses a lithium battery positive electrode with low cost and large cycling content in high temperature and its making method, and the second battery used this lithium battery. This positive electrode includes the collector, the first coating layer on the collector and the second coating layer on the first coating, and active materials of the first coating layer are at least one of sharp spar-shaped lithium manganate and the derivation of the lithium manganate, the active materials of the second coating layer are at least one of lithium cobalt, lithium cobalt derivation, lithium nickel and lithium nickel derivation.

Description

【Technical field】 [0001] The invention relates to a lithium battery cathode with low cost and improved cycle capacity at high temperature, a preparation method thereof, and a lithium ion secondary battery using the cathode. 【Background technique】 [0002] In recent years, with the demand for energy and the environment, environmentally friendly vehicles such as electric vehicles and electric bicycles have attracted attention, and some of them are being put into practical use. As an energy provider for electric vehicles, batteries must have large capacity and good cycle performance. Lithium-ion secondary batteries are being used more and more for their advantages such as high voltage, light weight, no memory effect, long cycle life and no environmental pollution. Many people accept it. [0003] For positive electrode active materials for rechargeable lithium batteries, chalcogenides that intercalate or release lithium ions are used, and typical positive electrode active mater...

AI Technical Summary

Problems solved by technology

Due to the incompatibility of the structure when the two phases coexist, the electrical contact between the electrode material particles is poor, and the diffusion of lithium ions is difficult.

The volume change caused by the cubic to tetragonal phase transition also results in a loss of capacity

[0010] Tests have proved that both the dissolution of Mn and the Jahn-Teller effect mainly occur at the end of the material discharge (the average valence of Mn is around +3.5), and at this time, the surface of the spinel lithium manganate particles on the surface of the pole piece is prone to local overheating. Discharge, the valence of Mn here is lower than +3.5, and the dissolution of Mn and the Jahn-Teller effect are very prone to occur. Cycles at high temperatures will aggravate these two main processes that lead to capacity fading

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