FIRG026 - Void growth within Li electrodes in solid electrolyte cells
FIRG026 - Void growth within Li electrodes in solid electrolyte cells
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FIRG026 - 固体电解质电池中锂电极内的空洞生长
DOI：
10.1016/j.actamat.2022.118303
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发表时间：
2022
期刊：
影响因子：
9.4
通讯作者：
Agier J
中科院分区：
文献类型：
--
作者：
Agier J
通过建立一个框架来分析固态锂电池电极/电解质界面处空洞的生长，该框架使用Onsager形式主义来耦合锂电极的幂律蠕变变形和Li+通过单离子导体固体电解质的通量。对于界面电阻和电解质电导率的实际组合，界面通量的标准Butler-Volmer动力学不能提供足够的通量聚焦以引发空隙生长，因此采用修改的动力学，其中界面电阻通过蠕变Li电极内位错的存在而降低。在剥离条件下，由于通量集中在这些空隙的周边上总是较低，因此尺寸为100的预先存在的空隙收缩。然而，在半球形杂质颗粒周围的电极中的空间不均匀蠕变降低了界面电阻，从而显著的通量集中在杂质的外围。这种通量聚焦导致具有两种不同行为状态的空隙生长：（i）在低电流下稳定但形成小空隙，而（ii）在较高电流下形成大空隙，但这些最终崩溃。没有发现预测孤立空隙尺寸增长大于10 μ m的条件，这表明孤立空隙的增长不会导致电池失效。因此，我们提出了一个假设，在剥离电极过程中，在界面上沉积的杂质颗粒周围开始的空隙的聚结。随后的预测是一致的测量单元故障，并提供线索的故障机制，由于空隙的增长。
The growth of voids at the electrode/electrolyte interface of a solid state Li battery is analysed by establishing a framework that uses the Onsager formalism to couple the power-law creep deformation of the Li electrode and flux of L i+ through a single-ion conductor solid electrolyte. For realistic combinations of the interfacial resistance and electrolyte conductivity, standard Butler-Volmer kinetics for the interfacial flux does not provide sufficient flux focussing to initiate void growth and so a modified kinetics is adopted where the interfacial resistance is decreased by the presence of dislocations within the creeping Li electrode. Micron-sized pre-existing voids shrink under stripping conditions as flux focussing on the periphery of these voids is always low. However, spatially inhomogeneous creep in the electrode around a hemispherical impurity particle reduces the interfacial resistance with consequent significant flux focussing at the periphery of the impurity. This flux focussing results in void growth with two distinct regimes of behaviour:(i) at low currents stable but small voids form while (ii) at higher currents large voids form but these ultimately collapse. No conditions are identified for which isolated voids are predicted to grow larger than 10 μ m in size suggesting that cell failure does not occur by the growth of isolated voids. We therefore propose a hypothesis for the coalescence of voids that initiate around impurity particles being deposited on the interface during stripping of the electrode. The ensuing predictions are consistent with measurements of cell failure and provide clues of the failure mechanisms due to void growth.