A lithium titanate secondary battery

A secondary battery and lithium titanate technology, which is applied in the field of lithium ion batteries, can solve the problems of affecting battery stability, low reduction potential, and inability to effectively isolate direct contact with the lithium titanate surface, so as to improve the low-temperature performance of the battery and reduce dissolution , Reduce the effect of battery gas production

Active Publication Date: 2019-04-23
GUANGZHOU TINCI MATERIALS TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, lithium titanate batteries are prone to gas generation at high temperatures, which affects the stability of the battery
The reason is that the reduction potential of the additive in the conventional electrolyte is low, and it cannot be used at a level higher than the plateau potential of lithium titanate (1.55V vs Li + / Li), the traditional electrolyte interface protective film SEI cannot effectively isolate the direct contact between the lithium titanate surface and the electrolyte, and the Ti-O active sites exist on the lithium titanate surface, which is easy to catalyze the decomposition of the electrolyte and its trace impurities to produce gas , especially at high temperature, the reaction is more obvious

Method used

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  • A lithium titanate secondary battery
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  • A lithium titanate secondary battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Preparation of PC-based electrolyte: in an argon atmosphere glove box (H 2 O6 ) and 0.03M lithium difluorophosphate (LiPO 2 f 2 ) electrolyte lithium salt, and then sequentially add 1% lithium tetrafluorooxalate phosphate (LTFOP) and 1.0% vinyl sulfate (DTD) based on the mass percentage of the electrolyte, and stir well to obtain the present invention. PC based electrolyte (free acid <15ppm, moisture <10ppm).

[0024] Preparation of nickel-cobalt lithium manganese oxide positive electrode sheet: nickel-cobalt lithium manganese oxide (type 111) is used as the positive electrode active material, and polyvinylidene fluoride (PVDF) and conductive carbon black (Super-P) are added in a mass ratio of 96:2:2 Mix in N-methylpyrrolidone (NMP) solvent, stir to obtain a slurry, apply it on both sides of the current collector aluminum foil on a coating machine, dry, cold press, and slitting to obtain a positive electrode sheet;

[0025] Preparation of lithium titanate negative el...

Embodiment 2~5

[0031] Embodiment 2~5 and comparative example 1~5

[0032] In Examples 2-5 and Comparative Examples 1-5, except that the composition of the electrolyte solution is added as shown in Table 1, the others are the same as in Example 1. Table 1 is the composition of the electrolyte solution and battery performance test results of Examples 1-5 and Comparative Examples 1-5:

[0033]

[0034] Table 1

[0035] In the above Table 1, the abbreviations / chemical formula corresponding names of each chemical substance are as follows:

[0036] PC (propylene carbonate), DEC (diethyl carbonate), EMC (ethyl methyl carbonate), PP (propyl propionate), EC (ethylene carbonate), LiPF 6 (lithium hexafluorophosphate), LiPO 2 f 2 (lithium difluorophosphate), LiFSI (lithium difluorosulfonimide), LiDFOB (lithium difluorooxalate borate).

[0037] From the comparison of the battery performance test results between the examples in Table 1 and Comparative Examples 1-4, it can be seen that lithium tetr...

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Abstract

The invention provides a lithium titanate secondary battery which comprises an anode pole piece, a cathode pole piece and PC-based electrolyte. The secondary battery is characterized in that the PC-based electrolyte is prepared from electrolyte lithium salt, lithium tetrafluoro(oxalato)phosphate (LTFOP), ethylene sulfate (DTD) and a PC-based organic solvent. According to the secondary battery, a film can be formed by reducing before charging and lithium-intercalation of a lithium titanate cathode by utilizing the high potential (1.75V vs Li+ / Li) reduction characteristic of lithium tetrafluoro(oxalato)phosphate, catalytic decomposition of the Ti-O active part in titanium titanate for electrolyte can be inhibited, and a lithium titanate battery is prevented from producing gas at high temperature; and oxygenolysis of electrolyte on the cathode surface and dissolution of transition metal ions in a cathode material can be reduced by utilizing the characteristic of ethylene sulfate forming a film on a cathode surface, and thus the circulating service life of a lithium titanate battery can be prolonged.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a PC-based electrolyte for lithium titanate secondary batteries and a lithium titanate battery using the electrolyte. Background technique [0002] Due to the advantages of high working voltage, high energy density, long life and environmental friendliness, lithium-ion batteries are widely used in 3C digital products, power tools, electric vehicles, aerospace and other fields. [0003] As a new negative electrode material for lithium secondary batteries, lithium titanate has many advantages, such as: 1. Lithium titanate itself is non-flammable and has higher safety than graphite; 2. Lithium titanate plateau potential (1.55V vs Li + / Li) is high, there will be no problem of lithium analysis, and the discharge voltage is stable; 3. In the process of deintercalating lithium ions, it is known as "zero strain material" and has good cycle stability; 4. Lithium titanate Solid phase...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M10/0567H01M10/0569H01M10/0525
CPCH01M10/0525H01M10/0567H01M10/0569H01M2300/0037Y02E60/10
Inventor 吕家斌潘立宁徐朝银万华平彭宏伟
Owner GUANGZHOU TINCI MATERIALS TECH
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