耐高電壓鋰離子電池電解液的開發(fā)研究
[Abstract]:Electrolyte is an indispensable part of lithium ion battery, which restricts the safety and stability of battery to a great extent. Nowadays, the demand for energy density of battery is more and more high, and a series of high voltage cathode materials, represented by LiNi0.5Mn1.5O4, have appeared. Therefore, the research of high voltage electrolyte has been paid more and more attention. Although there are some research reports on solvent and additive of new high voltage electrolyte, there is still a big gap from commercial application. In this paper, by comparing the electrochemical window and ionic conductivity of succinonitrile and adiponitrile, it is confirmed that the physical properties of the mixed electrolyte can be optimized by adding 5% of carbonic acid ester. The performance of cathode material LiNi0.5Mn1.5O4 in electrolyte was studied by charge-discharge test, but the cycling performance was not good. Adding proper amount of lithium diacetate borate to the mixed electrolyte could improve the performance of the electrolyte at the rate of 2C. After 200 cycles, the performance of the electrolyte was improved. Capacity only attenuates by 11. In addition, the cyclic stability of LiNi0.5Mn1.5O4 positive electrode in ordinary electrolyte was studied. The initial discharge specific capacity of 0.2C is 124.5mAh g-1, and the charge / discharge voltage is 3.0-4.9 V. The capacity maintenance rates of 1C and 2C cycles in the interval are 90% and 92%, respectively, when ordinary electrolytes are used, The capacity maintenance rate was only 48% and 47%. The action mechanism of succinic anhydride was studied. The oxidation potential of succinic anhydride was lower than that of carbonate by linear voltammetry. A good interfacial film is formed on the surface of the cathode material. On the one hand, the contact between the electrolyte and the cathode material is isolated and the side reactions between them are reduced; on the other hand, the conductivity of the material can be increased, which is favorable to the deintercalation and embedding of the lithium ion. Thus, the cyclic stability of high pressure cathode materials is improved. The application of other three kinds of additives in high-voltage electrolyte was also investigated. By testing the cycle stability, it is found that after adding 1% phthalic anhydride, the high rate performance of Li / LiNi0.5Mn1.5O4 battery is very good, and the cycle capacity of 200 cycles hardly attenuates, and the mechanism of its action remains to be further studied. Ethylfluorocarbonate was used to replace ethylene carbonate and mixed with butylene nitrile. The mixed electrolyte has a electrochemical stabilization window of up to 5 V. However, it is regrettable that ethylfluorocarbonate has not improved the compatibility between butylonitrile and cathode materials, which leads to the poor cycling performance of LiNi0.5Mn1.5O4 materials. It is suspected that the addition of too much or too little may be the reason for further experimental exploration.
【學(xué)位授予單位】:華南理工大學(xué)
【學(xué)位級(jí)別】:碩士
【學(xué)位授予年份】:2014
【分類號(hào)】:TM912
【共引文獻(xiàn)】
相關(guān)博士學(xué)位論文 前10條
1 廖友好;鋰離子電池安全型電解質(zhì)的制備及性能研究[D];華南理工大學(xué);2013年
2 劉建生;鋰離子電池新型凝膠聚合物電解質(zhì)的改性研究[D];華南理工大學(xué);2013年
3 吳賢文;功能電解液對(duì)LiMn_2O_4和LiNi_(0.5)Mn_(1.5)O_4電化學(xué)性能改善及其機(jī)理研究[D];中南大學(xué);2013年
4 文志剛;金屬氧化物微/納米結(jié)構(gòu)的合成、表征及其在鋰離子電池中的應(yīng)用研究[D];中南大學(xué);2013年
5 夏陽;生物模板法構(gòu)筑多級(jí)多孔結(jié)構(gòu)電極材料及其儲(chǔ)鋰性能研究[D];浙江工業(yè)大學(xué);2013年
6 裴啟飛;AlCl_3-BMIC離子液體電解精煉鋁中雜質(zhì)行為研究[D];昆明理工大學(xué);2012年
7 柳志民;高性能鈦氧化物負(fù)極材料制備及其電化學(xué)性能研究[D];哈爾濱工業(yè)大學(xué);2012年
8 李娜;高功率柔性鋰離子電池電極材料的制備及其性能研究[D];中國科學(xué)技術(shù)大學(xué);2013年
9 陳立鋒;碳基復(fù)合材料的設(shè)計(jì)、規(guī)模化制備及其在超級(jí)電容器中的應(yīng)用[D];中國科學(xué)技術(shù)大學(xué);2013年
10 鄭立炎;電致化學(xué)發(fā)光新材料的研究[D];福州大學(xué);2011年
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