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Degradation Mechanism of Dimethyl Carbonate (DMC) Dissociation on the LiCoO2 Cathode Surface: A First-Principles Study
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2017-10-09 00:00:00 , DOI: 10.1021/acsami.7b09352 Liyuan Huai 1 , Zhenlian Chen 1 , Jun Li 1
ACS Applied Materials & Interfaces ( IF 8.3 ) Pub Date : 2017-10-09 00:00:00 , DOI: 10.1021/acsami.7b09352 Liyuan Huai 1 , Zhenlian Chen 1 , Jun Li 1
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The degradation mechanism of dimethyl carbonate electrolyte dissociation on the (010) surfaces of LiCoO2 and delithiated Li1/3CoO2 were investigated by periodic density functional theory. The high-throughput Madelung matrix calculation was employed to screen possible Li1/3CoO2 supercells for models of the charged state at 4.5 V. The result shows that the Li1/3CoO2(010) surface presents much stronger attraction toward dimethyl carbonate molecule with the adsorption energy of −1.98 eV than the LiCoO2(010) surface does. The C–H bond scission is the most possible dissociation mechanism of dimethyl carbonate on both surfaces, whereas the C–O bond scission of carboxyl is unlikely to occur. The energy barrier for the C–H bond scission is slightly lower on Li1/3CoO2(010) surface. The kinetic analysis further shows that the reaction rate of the C–H bond scission is much higher than that of the C–O bond scission of methoxyl by a factor of about 103 on both surfaces in the temperature range of 283–333 K, indicating that the C–H bond scission is the exclusive dimethyl carbonate dissociation mechanism on the cycled LiCoO2(010) surface. This study provides the basis to understand and develop novel cathodes or electrolytes for improving the cathode–electrolyte interface.
中文翻译：
LiCoO 2阴极表面碳酸二甲酯（DMC）分解的降解机理：第一性原理研究
利用周期密度泛函理论研究了碳酸锂二甲酯在LiCoO 2（010）和去锂化的Li 1/3 CoO 2的表面上离解的降解机理。高通量的Madelung矩阵计算用于筛选4.5 V充电状态模型中可能的Li 1/3 CoO 2超级电池。结果表明，Li 1/3 CoO 2（010）表面对二甲基有更强的吸引力碳酸盐分子，其吸附能比LiCoO 2为-1.98 eV（010）表面呢。C–H键断裂是碳酸二甲酯在两个表面上最可能的解离机理，而羧基的C–O键断裂则不太可能发生。Li 1/3 CoO 2（010）表面的C–H键断裂的能垒略低。动力学分析进一步表明，在283–333 K的温度范围内，两个表面上C–H键断裂的反应速率比甲氧基的C–O键断裂的反应速率高出约10 3倍，表明CH键断裂是循环的LiCoO 2上唯一的碳酸二甲酯解离机理（010）表面。该研究为理解和开发新型阴极或电解质以改善阴极-电解质界面提供了基础。
更新日期：2017-10-09
中文翻译：
LiCoO 2阴极表面碳酸二甲酯（DMC）分解的降解机理：第一性原理研究
利用周期密度泛函理论研究了碳酸锂二甲酯在LiCoO 2（010）和去锂化的Li 1/3 CoO 2的表面上离解的降解机理。高通量的Madelung矩阵计算用于筛选4.5 V充电状态模型中可能的Li 1/3 CoO 2超级电池。结果表明，Li 1/3 CoO 2（010）表面对二甲基有更强的吸引力碳酸盐分子，其吸附能比LiCoO 2为-1.98 eV（010）表面呢。C–H键断裂是碳酸二甲酯在两个表面上最可能的解离机理，而羧基的C–O键断裂则不太可能发生。Li 1/3 CoO 2（010）表面的C–H键断裂的能垒略低。动力学分析进一步表明，在283–333 K的温度范围内，两个表面上C–H键断裂的反应速率比甲氧基的C–O键断裂的反应速率高出约10 3倍，表明CH键断裂是循环的LiCoO 2上唯一的碳酸二甲酯解离机理（010）表面。该研究为理解和开发新型阴极或电解质以改善阴极-电解质界面提供了基础。
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