Müller Philipp, Szczuka Conrad, Tsai Chih-Long, Schöner Sandro, Windmüller Anna, Yu Shicheng, Steinle Dominik, Tempel Hermann, Bresser Dominic, Kungl Hans, Eichel Rüdiger-A
Institut für Energie- und Klimaforschung (IEK-9: Grundlagen der Elektrochemie), Forschungszentrum Jülich, Jülich 52425, Germany.
Institut für Materialien und Prozesse für elektrochemische Energiespeicher- und wandler, RWTH Aachen University, Aachen 52074, Germany.
ACS Appl Mater Interfaces. 2024 Jun 26;16(25):32209-32219. doi: 10.1021/acsami.4c03387. Epub 2024 Jun 11.
Solid-state polymer electrolytes (SPEs), such as poly(ethylene oxide) (PEO), have good flexibility when compared to ceramic-type solid electrolytes. Therefore, it could be an ideal solid electrolyte for zero-excess all-solid-state Li metal battery (ZESSLB), also known as anode-free all-solid-state Li battery, development by offering better contact to the Cu current collector. However, the low Coulombic efficiencies observed from polymer type solid-state Li batteries (SSLBs) raise the concern that PEO may consume the limited amount of Li in ZESSLB to fail the system. Here, we designed ZESSLBs by using all-ceramic half-cells and an extra PEO electrolyte interlayer to study the reactivity between PEO and freshly deposited Li under a real battery operating conduction. By shuttling active Li back from the anode to the cathode, the PEO SPEs can be separated from the ZESSLBs for experimental studies without the influence from cathode materials or possible contamination from the usage of Li foil as the anode. Electrochemical cycling of ZESSLBs shows that the capacities of ZESSLBs with solvent-free and solvent-casted PEO SPEs significantly degraded compared to the ones with Li metal as the anode for the all-solid-state Li batteries. The fast capacity degradation of ZESSLBs using different types of PEO SPEs is evidenced to be associated with Li reacting with PEO, residual solvent, and water in PEO and dead Li formation upon the presence or absence of residual solvent. The results suggest that avoiding direct contact between the PEO electrolyte and deposited lithium is necessary when there is only a limited amount of Li available in ZESSLBs.
与陶瓷类固体电解质相比，固态聚合物电解质（SPEs），如聚环氧乙烷（PEO），具有良好的柔韧性。因此，它可能是零过量全固态锂金属电池（ZESSLB）的理想固体电解质，ZESSLB也被称为无阳极全固态锂电池，通过与铜集流体提供更好的接触来进行开发。然而，从聚合物型固态锂电池（SSLBs）中观察到的低库仑效率引发了人们的担忧，即PEO可能会消耗ZESSLB中有限量的锂，从而导致系统失效。在这里，我们通过使用全陶瓷半电池和额外的PEO电解质夹层来设计ZESSLB，以研究在实际电池运行传导下PEO与新沉积锂之间的反应活性。通过将活性锂从阳极穿梭回阴极，PEO SPEs可以与ZESSLB分离，以便进行实验研究，而不受阴极材料的影响或使用锂箔作为阳极可能带来的污染。ZESSLB的电化学循环表明，与以锂金属作为全固态锂电池阳极的情况相比，使用无溶剂和溶剂浇铸PEO SPEs的ZESSLB的容量显著下降。使用不同类型PEO SPEs的ZESSLB的快速容量下降被证明与锂与PEO、PEO中的残留溶剂和水的反应以及在有或没有残留溶剂的情况下形成死锂有关。结果表明，当ZESSLB中只有有限量的锂可用时，避免PEO电解质与沉积锂直接接触是必要的。
