Electrolyte adaptive to silicon-carbon negative electrode and lithium ion battery

An electrolyte and negative electrode technology, which is applied in the field of electrolyte and lithium-ion batteries, can solve the problems of destroying the structural stability of positive active materials, the dissolution of positive transition metal ions, and the acceleration of electrolyte decomposition to produce gas, etc., to achieve inhibition of metal ion dissolution, Improve the continuous repair ability and improve the effect of electrochemical performance

Pending Publication Date: 2020-04-21
HUIZHOU LIWINON NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the particularity of silicon-carbon anode materials, a large amount of FEC is usually required, and FEC is easy to decompose and produce gas under high temperature environment, and its decomposition product HF acid will destroy the structural stability of the positive electrode active material, resulting in the dissolution of positive transition metal ions. Accelerate electrolyte decomposition to produce gas and degrade high temperature storage performance

Method used

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  • Electrolyte adaptive to silicon-carbon negative electrode and lithium ion battery
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  • Electrolyte adaptive to silicon-carbon negative electrode and lithium ion battery

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Preparation of electrolyte: In a glove box filled with argon, ethylene carbonate, ethyl methyl carbonate and diethyl carbonate were mixed in a mass ratio of EC:EMC:DEC=3:2:5, and then added to the mixed solution. Slowly add 13.0 wt% lithium hexafluorophosphate (LiPF) based on the total weight of the electrolyte. 6 ), 0.5 wt % lithium difluorophosphate (LiPO) based on the total weight of the electrolyte 2 F 2 ) and 2.5 wt % lithium bisfluorosulfonimide (LiFSI) based on the total weight of the electrolyte, and finally, 1.0 wt % based on the total weight of the electrolyte of compound A with the structure of formula I, 0.3 wt % of compound A with the structure of formula II Compound B, 10 wt % of fluoroethylene carbonate (FEC) and 0.5 wt % of ethylene sulfate (DTD) were mixed to obtain the electrolyte of Example 1.

[0035] Preparation of soft pack battery: the prepared positive electrode sheet (active material LiCoO 2 ), the diaphragm and the negative electrode sheet (...

Embodiment 2-14

[0036] Examples 2-14 and Comparative Examples 1-9

[0037] In Examples 2-14 and Comparative Examples 1-9, except that the composition ratio of each component of the electrolyte solution is added as shown in Table 1, the rest are the same as those in Example 1. In addition, the structural formula of the additive of formula I and the structural formula of the additive of formula II in each embodiment are shown in Table 2.

[0038] Table 1 embodiment 1-14 and the electrolyte composition ratio of each component of comparative example 1-9

[0039]

[0040]

[0041]

[0042] Structural Formula I and Structural Formula II Specific Substance Descriptions in the Examples of Table 2

[0043]

[0044]

[0045] Performance Testing

[0046] Relevant performance tests were carried out on the batteries prepared in Examples 1-14 and Comparative Examples 1-9 and their electrolytes.

[0047] (1) Normal temperature cycle performance test: At 25°C, the battery after capacity div...

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Abstract

The invention belongs to the technical field of lithium ion batteries and especially relates to an electrolyte adaptive to a silicon-carbon negative electrode and a lithium ion battery. The electrolyte comprises electrolyte lithium salt, a non-aqueous organic solvent and additives, and the additives comprise a compound additive A with a structure as shown in a formula I, a compound additive B withthe structure as shown in a formula II, a film-forming additive C and a lithium salt additive D. Compared with the prior art, by using the lithium ion battery electrolyte adaptive to the silicon-carbon negative electrode, through a synergistic effect of the additive A, the additive B, the additive C and the additive D, the electrolyte has excellent film forming performance on a surface of the silicon-carbon negative electrode so that cycle performance, high-temperature storage performance and the like of the silicon-carbon negative electrode lithium ion battery are effectively improved, and problems of volume expansion, cycle diving and the like in a charging and discharging process of the silicon-carbon negative electrode battery in the prior art are well solved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to an electrolyte suitable for a silicon carbon negative electrode and a lithium ion battery. Background technique [0002] In order to meet the growing demand for high energy density and high power density of lithium-ion batteries in portable electronic devices and new energy vehicles, it is imperative to develop battery systems with high energy density. Silicon due to its high specific capacity (3579mAh g -1 ) and low operating voltage plateau (relative to Li / Li + 0.1-0.5V) and abundant reserves, it is a promising anode material for next-generation lithium-ion batteries. However, the volume expansion of silicon (>300%) during the charge-discharge process of silicon anodes can lead to severe particle pulverization and destruction of the solid electrolyte interphase layer, resulting in battery capacity fading and poor cycling performance. Therefore, p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M10/0567H01M10/42H01M10/0525
CPCH01M10/0525H01M10/0567H01M10/4235H01M2300/0025Y02E60/10
Inventor 张丽娟周槐李江蓝杨山陈杰李载波
Owner HUIZHOU LIWINON NEW ENERGY TECH CO LTD
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