Electrolyte for lithium secondary battery and lithium secondary battery containing the same

A lithium secondary battery and electrolyte technology, which is applied in the direction of non-aqueous electrolyte batteries, secondary batteries, electrolytes, etc., can solve the problems of elution and destruction of positive electrode transition metals, etc.

Active Publication Date: 2020-07-31

HYUNDAI MOTOR CO LTD +2

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AI-Extracted Technical Summary

Problems solved by technology

[0008]For example, HF may destroy the CEI of the positive electrode and the SEI of the negati...

Method used

[0094] Therefore, the carbonate-based solvent (EC, EMC, DMC, DEC) can preferably be used as a solvent in combin...

Abstract

Disclosed are an electrolyte for a lithium secondary battery and a lithium secondary battery containing the same. The electrolyte for the lithium secondary battery includes a lithium salt, a solvent component and an additive including one or more of the following compounds,wherein each of R1, R2and R3is independently hydrogen, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3to 20 carbon atoms, an aryl group having 6 to 30 carbon atoms, or an arylalkyl group having 6 to 30 carbon atoms.

Application Domain

Li-accumulatorsOrganic electrolytes +1

Technology Topic

ElectrolyteCarbon atom +3

Image

Examples

Experimental program(3)
Comparison scheme(2)
Effect test(1)

Example Embodiment

[0125] Preparation of Example 1

[0126] Example 1 was prepared under the same conditions as Comparative Example 1, except that the electrolyte further contained an additive of the following chemical formula (1).

[0127] Chemical formula (1)

[0128]

Example Embodiment

[0129] Preparation of Example 2

[0130] Example 2 was prepared under the same conditions as Comparative Example 1, except that the electrolyte further contained an additive of the following chemical formula (2).

[0131] Chemical formula (2)

[0132]

Example Embodiment

[0133] Preparation of Example 3

[0134] Example 3 was prepared under the same conditions as Comparative Example 1, except that the electrolyte further contained an additive of the following chemical formula (3).

[0135] Chemical formula (3)

[0136]

[0137] Preparation of Examples 4-6

[0138] Example 4 was prepared under the same conditions as Comparative Example 2, except that the electrolyte further contained 0.5% by weight of the additive of formula (1) based on the total weight of the electrolyte.

[0139] Example 5 was prepared under the same conditions as Comparative Example 2, except that the electrolyte further contained 0.5% by weight of the additive of formula (2) based on the total weight of the electrolyte.

[0140] Example 6 was prepared under the same conditions as Comparative Example 3, except that the electrolyte further contained 0.5% by weight of the additive of formula (3) based on the total weight of the electrolyte.

[0141] Preparation of Examples 7-9

[0142] Examples 7-9 were prepared under the same conditions as Comparative Example 1, except that the electrolyte further contained 0.5 wt %, 1 wt % and 3 wt % of the additive of formula (1) based on the total weight of the electrolyte, respectively.

[0143] The performance of the lithium secondary batteries of each example and each comparative example will be evaluated below.

[0144] (1) Evaluation of HF scavenging effect

[0145] In order to analyze the HF scavenging effect, by 19 F NMR (Nuclear Magnetic Resonance) measurements test the HF content. Figure 1A The comparative example 1 is shown 19 Results of F NMR measurements, Figures 1B to 1D Corresponding to Examples 1-3 respectively 19 F NMR measurement results. Examples 1 to 3 of the present invention included 1 wt% of the additives of formulae (1) to (3) and were tested after mixing for 1 hour 19 FNMR.

[0146] exist 1A to 1D , the HF is at about -155ppm 19 The F resonance peak, corresponding to the HF 19 F resonance, the TMSF is at about -156.4 ppm, -156.7 ppm and -157 ppm 19 F resonance peak, corresponding to trimethylsilyl fluoride (TMSF) 19 F resonance. In addition, the above numerical values for HF and TMSF represent a quantitative comparison of the relative signal intensities of HF and TMSF.

[0147] like Figures 1A-1D As shown, the HF of Examples 1 to 3 19 The signal intensity of the F formant is smaller than that of the HF of Comparative Example 1 19 The signal intensity of the F formant and the formation of the TMSF 19 F resonance peak, it can be proved that the additives of chemical formulae (1) to (3) have the effect of scavenging HF by the following reaction formulae (2) to (4).

[0148] Reaction formula (2)

[0149]

[0150] Reaction formula (3)

[0151]

[0152] Reaction formula (4)

[0153]

[0154] Furthermore, in the case of Example 1 of Examples 1-3, the HF 19 The signal intensity of the F formant was reduced the most, the HF was cleared the most, and the TMSF formed by the cleared HF had the most 19 The F formant has the strongest signal intensity. From this, it can be seen that the aminosilyl group (N-Si) has a better HF scavenging effect, and it can be seen that the additive of chemical formula (1) of Example 1 has more excellent HF scavenging effect than the additives of chemical formulas (2) to (3). Good HF removal effect.

[0155] (2) Evaluation of ionic conductivity

PUM

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