Electrolyte applicable to silicon carbon negative and lithium ion battery comprising electrolyte

An electrolyte and negative electrode technology, applied in secondary batteries, secondary battery repair/maintenance, circuits, etc., can solve the problems of SEI film instability, battery capacity decay, SEI damage, etc., to inhibit reduction and decomposition, and improve discharge capacity. , the effect of reducing the interface impedance

Active Publication Date: 2019-06-11
SHANSHAN ADVANCED MATERIALS QUZHOU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The SEI film formed by the conventional electrolyte system on the surface of the silicon carbon negative electrode is unstable, and it is easy to cause SEI damage and shedding due to the volume effect in the charging and discharging process, resulting in a rapid decline in battery capacity

Method used

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  • Electrolyte applicable to silicon carbon negative and lithium ion battery comprising electrolyte
  • Electrolyte applicable to silicon carbon negative and lithium ion battery comprising electrolyte
  • Electrolyte applicable to silicon carbon negative and lithium ion battery comprising electrolyte

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Preparation of electrolyte: In a glove box filled with argon, mix ethylene carbonate, diethyl carbonate and ethyl methyl carbonate according to the mass ratio of EC:DEC:EMC=2:3:3, and then add to the mixed solution Slowly add 12.5wt% lithium hexafluorophosphate (LiPF 6 ), based on 0.5wt% lithium bisoxalate borate (LiBOB) based on the total mass of the electrolyte and 2.5wt% lithium difluorooxalate borate (LiDFOB) based on the total mass of the electrolyte, and finally add 2.0wt% based on the total mass of the electrolyte Fluorophenylisocyanate compounds having the structure shown in formula I, 0.5wt% disilazide-based compounds having the structure shown in formula II, 5.0wt% fluoroethylene carbonate (FEC) and 0.5wt% 1, 3-propanediol cyclic sulfate (PCS), after being stirred uniformly, obtains the lithium-ion battery electrolyte of embodiment 1.

[0042] Preparation of soft-pack battery: stack the prepared positive electrode sheet, separator, and negative electrode shee...

Embodiment 2-12 and comparative example 1-8

[0044] In Examples 2-12 and Comparative Examples 1-8, except that the composition ratio of the components of the electrolyte is in accordance with the additives shown in Table 1, the others are the same as in Example 1.

[0045] Table 1 embodiment 1-12 and the composition ratio of each component of the electrolyte of comparative example 1-8

[0046]

[0047]

[0048]

[0049] The following performance tests were carried out on the full batteries prepared in Examples 1-12 and Comparative Examples 1-8:

[0050] 1) Cycling performance test at room temperature: At 25°C, charge the divided battery to 4.2V at 1C constant current and constant voltage, with a cut-off current of 0.05C, then discharge at 1C constant current to 3.0V, and cycle accordingly, charge / Calculate the capacity retention rate of the 1000th cycle after discharging 1000 cycles, the calculation formula is as follows:

[0051] 1000th cycle capacity retention rate (%)=(1000th cycle discharge capacity / first ...

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Abstract

The invention belongs to the technical field of a lithium ion battery, and particularly relates to an electrolyte applicable to a silicon carbon negative and a lithium ion battery comprising the electrolyte. The electrolyte comprises an electrolyte lithium salt, a non-aqueous organic solvent and an additive. Wherein the additive comprises a negative film formation additive, a fluorine-substitutedphenyl isocyanate compound additive with a formula I structure and a dosilane nitrogen-based compound additive. Compared with the prior art, the actual discharging capability, the cycle stability andthe high-temperature storage performance of a silicon carbon negative electrode lithium ion battery are effectively improved by means of a synergic effect generated by combined application of variousadditives, gas generation is prevented, the problems of volume expansion and pole plate pulverization of the battery during the charge-discharge process are solved very well, and meanwhile, the electrolyte is compatible with relatively good high- and low-temperature performance.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to an electrolyte suitable for a silicon-carbon negative electrode and a lithium ion battery containing the electrolyte. Background technique [0002] Lithium-ion batteries are widely used in 3C digital, electric tools, aerospace, energy storage, power vehicles and other fields due to their advantages such as high specific energy, no memory effect, and long cycle life. The rapid development of electronic information technology and consumer products has a great impact on lithium-ion batteries. Battery energy density performance puts forward higher requirements. At present, commercial lithium-ion batteries mainly use graphite as the negative electrode material, but the maximum theoretical specific capacity of graphite is only 372mAh / g, which is comparable to positive electrode materials such as lithium cobaltate, lithium manganate, lithium iron phosphate, and nickel-coba...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0567H01M10/0568H01M10/0525H01M10/42
CPCY02E60/10
Inventor 张丽娟大浦靖郭力
Owner SHANSHAN ADVANCED MATERIALS QUZHOU CO LTD
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