论文标题
高压尖晶石表面上表面膜的阳极分解 - 密度函数理论和实验研究
Anodic Decomposition of Surface Films on High Voltage Spinel Surfaces -- Density Function Theory and Experimental Study
论文作者
论文摘要
在高压锂离子电池中，在阴极材料界面处有机溶剂液体电解质的氧化分解已被确定为快速容量褪色的主要原因。最近也已证明，“阴极电解质间相相：（CEI）膜部分或完全由电解质分解产物组成，与高电位的电池循环行为相关。使用密度功能理论（DFT）计算，杂交PBE0功能，以及（001）的表面（001）的表面，请先研究两种型号。碳酸盐（EC）溶剂分子被预测在LI（X）Mn（2）O（2）O（2）O（4）（001）表面上被氧化，以适度的操作电压，从而形成吸附的有机片段，以释放CO2气体的进一步氧化性碎片。 Li（X）Ni（0.5）Mn（1.5）O（4）（LNMO）在较小的X值下，我们认为涉及CEI膜的首次形成，然后在较高的电位上进一步氧化CEI，与容量淡出的机制最相关。探索。
Oxidative decomposition of organic-solvent-based liquid electrolytes at cathode material interfaces has been identified as a main reason for rapid capacity fade in high-voltage lithium ion batteries. The evolution of "cathode electrolyte interphase: (CEI) films, partly or completely consisting of electrolyte decomposition products, has also recently been demonstrated to be correlated with battery cycling behavior at high potentials. Using Density Functional Theory (DFT) calculations, the hybrid PBE0 functional, and the (001) surfaces of spinel oxides as models, we examine these two interrelated processes. Consistent with previous calculations, ethylene carbonate (EC) solvent molecules are predicted to be readily oxidized on the Li(x)Mn(2)O(4) (001) surface at modest operational voltages, forming adsorbed organic fragments. Further oxidative decompostion of such CEI fragments to release CO2 gas is however predicted to require higher voltages consistent with Li(x)Ni(0.5)Mn(1.5)O(4) (LNMO) at smaller x values. We argue that multi-step reactions, involving first formation of CEI films and then further oxidization of CEI at higher potentials, are most relevant to capacity fade. Mechanisms associated with dissolution or oxidation of native Li2CO3 films, which is removed before the electrolyte is in contact with oxide surfaces, are also explored.
