Fundamental Studies on the Impedance of Lithium All-Solid-State Batteries

锂全固态电池（ASSB）的阻抗主要取决于电池内部的固体颗粒（Li嵌入活性材料颗粒和固体电解质颗粒）之间的接触，从而取决于所施加的堆压力。这种电池类型的阻抗谱由不同的贡献，这还不能以明确的方式归因于阳极，阴极和界面处的过程。 在这个项目中，将开发一种系统的方法来分析和解释ASSB的阻抗谱，目的是实现一个明确的属性的阻抗贡献的过程中的ASSB。ASSB将由In-Li阳极、固体电解质隔膜和复合阴极组成。在复合阴极中，活性材料颗粒（分别为单晶和多晶LiNi 0.6Mn 0.2Co 0.2O2）、固体电解质颗粒（分别为Li5.3PS 4.3ClBr 0.7和Li2.5Y 0.5Zr 0.5Cl 6）和炭黑将以不同的体积比混合。ASSB将在一个专门设计的测量系统中进行循环，该系统具有主动压力和温度控制，并将在不同的堆压和充电状态下收集阻抗谱。 对于ASSB的阻抗谱的分析和解释，将使用以下方法：（i）对称电池（阳极）上的阻抗测量|固体电解质|阳极），（阴极|固体电解质|阴极）和（阳极|固体电解质|阴极|固体电解质|阳极）将提供关于阳极、阴极和界面的阻抗贡献的信息;（ii）具有不同阴极厚度的ASSB上的阻抗测量对于区分固体颗粒的离子传输电阻和活性材料处的电荷转移电阻将是重要的|固体电解质界面 阴极的阻抗贡献的分析将基于合适的传输线模型。阴极内部的电荷转移电阻的值将根据材料组合、堆压力和充电状态获得。这些值将与含有液体电解质的常规锂离子电池的复合阴极的公开值进行比较。

The impedance of a lithium all-solid-state battery (ASSB) depends critically on the contacts between the solid particles (Li intercalating active material particles and solid electrolyte particles) inside the battery and thus on the applied stack pressure. The impedance spectra of this battery type consist of different contributions, which could not yet be attributed in an unambiguous fashion to processes in the anode, in the cathode, and at interfaces. In this project, a systematic approach for the analysis and interpretation of the impedance spectra of ASSBs will be developed with the aim to achieve a clear-cut attribution of impedance contributions to processes in the ASSBs. The ASSBs will consist of an In-Li anode, a solid electrolyte separator and a composite cathode. In the composite cathode, active material particles (single-crystalline and poly-crystalline LiNi0.6Mn0.2Co0.2O2, respectively), solid electrolyte particles (Li5.3PS4.3ClBr0.7 and Li2.5Y0.5Zr0.5Cl6, respectively) and carbon black will be mixed in different volume ratios. The ASSBs will be cycled in a specifically designed measuring system with active pressure and tempertur control, and the impedance spectra will be collected at different stack pressures and states of charge. For the analysis and interpretation of the impedance spectra of the ASSBs, the following approach will be used: (i) Impedance measurements on symmetric cells (anode | solid electrolyte | anode), (cathode | solid electrolyte | cathode), and (anode | solid electrolyte | cathode | solid electrolyte | anode) will provide information on the impedance contributions of anode, cathode and interfaces; (ii) Impedance measurements on ASSBs with different cathode thickness will be important for differentiating between ion transport resistances of the solid particles and charge transfer resistance at the active material | solid electrolyte interfaces. The analysis of the impedance contribution of the cathode will be based on a suitable transmission-line model. Values for the charge transfer resistance inside the cathode will be obtained in dependence of the material combination, stack pressure, and state of charge. These values will be compared to published values for composite cathodes of conventional lithium-ion batteries containing a liquid electrolyte.