Improved electrolytes for Li-ion batteries: Mixtures of ionic liquid and organic electrolyte with enhanced safety and electrochemical performance
Improved electrolytes for Li-ion batteries: Mixtures of ionic liquid and organic electrolyte with enhanced safety and electrochemical performance
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DOI：
10.1016/j.jpowsour.2009.08.056
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发表时间：
2010-02-01
影响因子：
9.2
通讯作者：
Zaghib, K.
中科院分区：
文献类型：
--
作者：
Guerfi, A.;Dontigny, M.;Zaghib, K.
研究了以LiFePO4为阴极和石墨为阳极的混合电解质锂离子电池系统的物理和电化学特性。混合电解质是基于阴离子液体（IL）和商业电池中使用的有机溶剂。我们研究了一系列的成分，以确定最佳的电导率和不可燃性的混合电解质。这使我们研究了il与通常用于商用锂离子电池的有机电解质的混合物，即碳酸乙烯（EC）和碳酸二乙烯（DEC）。该IL电解质由（三氟甲基磺酰亚胺）（TFSI）为阴离子，1-乙基-3-甲基咪唑（EMI）为阳离子组成。其中一些混合物的物理和电化学性能比单独的组分有明显的改善。电解质混合物提高了安全性；当混合物中IL含量为>= 40%时，无可燃性。在这些混合电解质中，在MCMB石墨阳极上获得了稳定的SEI层。而含tfsi阴离子的IL则不能。LiFePO4的高倍率性能在有机电解质和1:1的混合物中是相似的。当电解液中加入Us时，LiFePO4阴极的界面电阻稳定。在C/12下，至少有一些有机电解质的电池获得了155 mAh g（-1）的可逆容量，而纯IL的电池只有124 mAh g（-1）。随着放电倍率的增加，容量保持接近有机溶剂的容量，直到2 C倍率。以更高的利率。混合电解质的结果开始偏离纯有机电解质电池。对LiFePO4//Li4Ti5O12锂离子电池的评价表明，有机电解质和40%电解质混合后的锂离子电池的一级CE分别为98.7和93.0%。两种电池配置的功率性能在高达2c的速率下相当。研究表明，有机溶剂和IL的混合使用可以提高锂离子电池的安全性和电化学性能。(C) 2009 Elsevier B.V.版权所有
Physical and electrochemical characteristics of Li-ion battery systems based on LiFePO4 cathodes and graphite anodes with mixture electrolytes were investigated. The mixed electrolytes are based on anionic liquid (IL), and organic solvents used in commercial batteries. We investigated a range of compositions to determine an optimum conductivity and non-flammability of the mixed electrolyte. This led us to examine mixtures of ILs with the organic electrolyte Usually employed in commercial Li-ion batteries, i.e., ethylene carbonate (EC) and diethylene carbonate (DEC). The IL electrolyte consisted of (trifluoromethyl sulfonylimide) (TFSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) as the cation. The physical and electrochemical properties of some of these mixtures showed an improvement characteristics compared to the constituents alone. The safety was improved with electrolyte mixtures; when IL content in the mixture is >= 40%, no flammability is observed. A stable SEI layer was obtained on the MCMB graphite anode in these mixed electrolytes. which is not obtained with IL containing the TFSI-anion. The high-rate capability of LiFePO4 is similar in the organic electrolyte and the mixture with a composition of 1:1. The interface resistance of the LiFePO4 cathode is stabilized when the Us added to the electrolyte. A reversible capacity of 155 mAh g(-1) at C/12 is obtained with cells having at least some organic electrolyte compared to only 124 mAh g(-1) with pure IL. With increasing discharge rate, the capacity is maintained close to that in the organic solvent up to 2 C rate. At higher rates. the results with mixture electrolytes start to deviate from the pure organic electrolyte cell. The evaluation of the Li-ion cells: LiFePO4//Li4Ti5O12 with organic and, 40% mixture electrolytes showed good 1st CE at 98.7 and 93.0%, respectively. The power performance of both cell configurations is comparable up to 2 C rate. This study indicates that safety and electrochemical performance of the Li-ion battery can be improved by using mixed IL and organic solvents. (C) 2009 Elsevier B.V. All rights reserved.