Lithium ion battery

Abstract

The invention discloses a lithium ion battery which comprises an anode piece, a cathode piece, an isolation film and electrolyte, wherein the anode piece comprises an anode flow collection body and ananode diaphragm which is attached on the anode flow collection body and contains an anode active substance, the cathode piece comprises a cathode flow collection body and a cathode diaphragm which isattached on the cathode flow collection body and contains a cathode active substance, an electrolyte solvent contains methylphosphoric acid dimethyl ester, and the cathode active substance is lithiumtitanate. In the lithium ion battery, the lithium titanate can not generate a reduction reaction with the methylphosphoric acid dimethyl ester because the platform electric potential of the lithium titanate is about 1.5V (Li+ / Li relatively) and is higher than the reduction electric potential of 1.2V (Li+ / Li relatively) of the methylphosphoric acid dimethyl ester, and the first-time efficiency andthe capacity of the lithium ion battery are not influenced.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to a lithium ion battery with good safety performance and electrochemical performance. Background technique [0002] With the development of science and technology, lithium-ion batteries, which have the advantages of high energy, high reliability, and good processability, are more and more popular, and are widely used in various portable electronic devices. [0003] Lithium-ion batteries generally include a positive electrode sheet, a negative electrode sheet, a separator, and an electrolyte. The positive electrode sheet includes a positive electrode collector and a positive electrode membrane attached to the positive electrode collector and contains a positive electrode active material. The negative electrode sheet includes a negative electrode collector and is attached to the negative electrode collector. Negative diaphragm containing negative active material on the fluid. However, there ...

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Problems solved by technology

[0005] However, see figure 1 , the lithium-ion battery in the above-mentioned prior art has at least the following defects: when the dimethyl methyl phosphate solvent is applied in the negative pole graphite system, it will undergo a reduction reaction with graphite at about 1.2V (relative to Li+ / Li), Leading to graphite peeling, the first efficiency and capacity of lithium-ion batteries are greatly lost, which affects the safety performance and electrochemical performance of lithium-ion batteries

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