Design-of-experiments-guided optimization of slurry-cast cathodes for solid-state batteries

• Published in: Cell reports physical science Vol. 2; no. 6; p. 100465
• Main Authors: Teo, Jun Hao, Strauss, Florian, Tripković, Đorđije, Schweidler, Simon, Ma, Yuan, Bianchini, Matteo, Janek, Jürgen, Brezesinski, Torsten
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 23.06.2021; Elsevier
• Subjects: all-solid-state battery; binder instability; design of experiments; gas evolution; layered Ni-rich oxide cathode; slurry-based processing; layered Ni-rich oxide cathode; all-solid-state battery; gas evolution; slurry-based processing; design of experiments; binder instability
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2021.100465

Laboratory research into bulk-type solid-state batteries (SSBs) has been focused predominantly on powder-based, pelletized cells and has been sufficient to evaluate fundamental limitations and tailor the constituents to some degree. However, to improve experimental reliability and for commercial implementation of this technology, competitive slurry-cast electrodes are required. Here, we report on the application of an approach guided by design of experiments (DoE) to evaluate the influence of the type/content of polymer binder and conductive carbon additive on the cyclability and processability of Li1+x(Ni0.6Co0.2Mn0.2)1−xO2 (NCM622) cathodes in SSB cells using lithium thiophosphate solid electrolytes. The predictions are verified by charge-discharge and impedance spectroscopy measurements. Furthermore, structural changes and gas evolution are monitored via X-ray diffraction and differential electrochemical mass spectrometry, respectively, in an attempt to rationalize and support the DoE results. In summary, the optimized combination of polymer binder and conductive carbon additive leads to high electrochemical performance and good processability. [Display omitted] Statistical optimization of slurry-cast NCM cathodes for solid-state batteriesCycling performance and processability correlate with binder chemistry and contentDesign of experiments (DoE) results are corroborated experimentallyOperando gas analysis reveals (electro-)chemical binder instability Teo et al. apply a statistical approach, DoE, to facilitate the transition from pelletized to slurry-cast cathodes for solid-state batteries. Datasets from electrochemical and mechanical tests are used to build a model that allows effective tailoring of the slurry recipe. The DoE predictions/results are evaluated using various analytical techniques.