Elimination of "Voltage Noise" of Poly (Ethylene Oxide)-Based Solid Electrolytes in High-Voltage Lithium Batteries: Linear versus Network Polymers
Elimination of "Voltage Noise" of Poly (Ethylene Oxide)-Based Solid Electrolytes in High-Voltage Lithium Batteries: Linear versus Network Polymers
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DOI：
10.1016/j.isci.2020.101225
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发表时间：
2020-06-26
期刊：
影响因子：
5.8
通讯作者：
Kasnatscheew, Johannes
中科院分区：
文献类型：
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作者：
Homann, Gerrit;Stolz, Lukas;Kasnatscheew, Johannes
通常，基于聚（环氧乙烷）（PEO）的固体聚合物电解质（SPE）显示出高压电极（例如锂金属电池中的LiNi0.6Mn0.2Co0.2O2）的故障，其可以被监测为充电期间“电压噪声”的任意出现，并且可以归因于Li枝晶诱导的电池微短路。当在半互穿网络（s-IPN）中引入线性PEO基SPE时，这种失效行为消失，甚至能够在40 ℃下实现足够的充电/放电循环性能。可以排除任何电解质氧化反应对性能差异的影响，因为两种SPE显示出类似的（高）体氧化起始电位，约为4.6 V，相对于Li垂直条Li+。相反，如压缩测试所揭示的，SPE的改进的机械性能被认为是决定性的，因为它们在机械上更好地承受Li枝晶穿透并且更好地保持两个电极的距离，这两者都使得电池短路的可能性更小。
Frequently, poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) reveal a failure with high-voltage electrodes, e.g. LiNi0.6Mn0.2Co0.2O2 in lithium metal batteries, which can be monitored as an arbitrary appearance of a "voltage noise" during charge and can be attributed to Li dendrite-induced cell micro short circuits. This failure behavior disappears when incorporating linear PEO-based SPE in a semi-interpenetrating network (s-IPN) and even enables an adequate charge/discharge cycling performance at 40 degrees C. An impact of any electrolyte oxidation reactions on the performance difference can be excluded, as both SPEs reveal similar (high) bulk oxidation onset potentials of approximate to 4.6 V versus Li vertical bar Li+. Instead, improved mechanical properties of the SPE, as revealed by compression tests, are assumed to be determining, as they mechanically better withstand Li dendrite penetration and better maintain the distance of the two electrodes, both rendering cell shorts less likely.