Search

All-solid-state lithium-sulfur batteries (ASSB-LiS batteries) are considered among advanced candidates for next-generation energy storage systems, as they break with restrictions and limitations that liquid electrolytes impose on lithium-ion batteries and lithium-sulfur batteries (LiS-batteries), meaning enhanced safety and higher energy densities. However, investigations under realistic conditions on pouch cell level are challenging, as it is necessary to implement a scalable preparation method for sheet-type cathodes with high sulfur utilization and loading. In this study, a solvent-free process to prepare free-standing cathode sheets with low binder content down to 0.1 wt% PTFE is demonstrated. The contribution of binder and electrolyte on the conversion reaction of sulfur is discussed. Sheet-type cathodes reach nearly theoretical sulfur utilization of 1672 mAh gS-1 and outstanding reversible capacity reten-tion with 72% of initial discharge capacity after 400 cycles by adapting cut-off voltages to the stability window of the electrolyte. Furthermore, an all-solid-state pouch cell is demonstrated using the dry-film cathode, which is suc-cessfully tested for 50 cycles at different C-rates. Thickness monitoring of the cell stack gives fundamental insights into the volume change and breathing behavior of both cathode and anode.

Columnar silicon (col-Si) is a great candidate as anode material to achieve volumetric energy density, outperforming state-of-the-art lithium-ion batteries. The utilization of col-Si in industrial scale is mainly restricted by poor cyclic life originating from immense volumetric expansion of Si, resulting in mechanical failure of the electrode. Understanding the mechanic and breathing behavior of col-Si films coupled with copper current collectors (Cu-CC) is therefore crucial to mitigate the above-mentioned issues. In this study, structure-mechanical changes of col-Si anodes, which are induced by stress evolution upon (de-)lithiation of Si, are investigated via operando electrochemical dilatometry and in situ thickness monitoring on material and stack level depending on Cu-CC thickness (10 and 18 µm) and state-of-charge/balancing factor (SoC / N/P ratio). Employing moderately thick Cu-CC (18 µm) prohibits electrode deformation significantly, achieving energy densities of 1101 and 873 Wh L-1 in multilayered-pouch cells for N/P ratios of 1.1 and 2.0, respectively. The volume uptake that takes place after the first cycle can strongly be reduced from ∆Vcell stack: 55% to 25% by adapting N/P: 2.0 instead of 1.1. Even after volumetric growth (lithiated state), energy densities around 700 Wh L-1 are still achievable, confirming the feasibility of the col-Si approach.