Fraunhofer Institute for Material and Beam Technology IWS
Fraunhofer Institute for Material and Beam Technology IWS

KaSiLi

Structural mechanical cathode adaptation on silicon- and lithium-based anode materials (KaSiLi)

New thin-film electrodes made of silicon and lithium for the “Research Fab Battery”

SEM cross-sectional image of an NMC cathode (lithium nickel cobalt manganese oxide) produced using the IWS dry film process.
© Fraunhofer IWS
SEM cross-sectional image of an NMC cathode (lithium nickel cobalt manganese oxide) produced using the IWS dry film process.

The project's overall objective is to develop high-energy cells (Li-S and LIB) based on lithium and silicon anodes increasing the energy density compared to conventional lithium-ion cells and minimizing the volume change during cycling.

The developments focus on high-energy cells based on silicon and lithium anodes, which allow an increase of the volumetric energy density of up to 65 % compared to conventional lithium ion cells. However, the significant charge-state dependent volume changes of these materials on the microscale are transferred to a (macroscopic) change in the thickness of the cells and thus lead to major challenges for the cell integration into battery systems. The present project addresses these challenges with innovative approaches to reduce the volume changes.

Important sub-steps in this process include the following:

SEM image of a silicon layer with defined structure: The anodes' properties in the battery application can be controlled by selectively adjusting the structure and thickness of the layers.
© Fraunhofer IWS
SEM image of a silicon layer with defined structure: The anodes' properties in the battery application can be controlled by selectively adjusting the structure and thickness of the layers.
By minimizing volume changes at the electrode level in Li-S and LIB prototype cells, high energy densities are to be detected at the cell level with simultaneous minimal thickness changes via the charge state.
© Fraunhofer IWS
By minimizing volume changes at the electrode level in Li-S and LIB prototype cells, high energy densities are to be detected at the cell level with simultaneous minimal thickness changes via the charge state.
Pouch cell construction in three stages: They are assembled by stacking individual layers of electrodes and separators. This enables industry-oriented material tests for a wide variety of cell systems.
© Fraunhofer IWS Dresden
Pouch cell construction in three stages: They are assembled by stacking individual layers of electrodes and separators. This enables industry-oriented material tests for a wide variety of cell systems.

Development of high-capacity Si and Li-based anodes

  • with increased cycle stability, minimized volume changes and higher volumetric capacity for high-energy cells by influencing the microstructure, the interface to the current collector, galvanic seeding approaches and by adapting the interface to the electrolyte system or to the current collector


Development of high capacity oxide and sulfur based cathodes

  • Development of Ni-rich NCM materials as cathode system for the design of high-energy lithium-ion cells based on Si and Li anodes
  • Development of sulfur/carbon composites as cathode system for the design of high-energy lithium sulfur cells based on thin-film lithium anodes


Structural mechanical and electrochemical adaptation for high energy cells

  • Adaptation of all cell components and balancing of the full cells while minimizing structural-mechanical changes and maximizing energy density for the cell systems Li/S8 and NMC/Si, as well as NMC/Li.


Prototype cell development based on lithium and silicon anodes

  • Model-based cell design for the design and construction of multi-layer pouch cells. By integrating innovative approaches to minimize volume changes at the electrode level in Li-S and LIB prototype cells, high energy densities with minimal thickness changes over the state of charge are to be demonstrated at cell level.


In addition, the KaSiLi project will actively contribute to the ExcellBattMat platforms by integrating the acquired know-how on the correlation of structural-mechanical and electrochemical changes at material, component and cell level, on the production of high-energy components and the development of prototype cells.

Research funding

The project KaSiLi was funded by the Federal Ministry of Education and Research under the number 03XP0254 A-D.

Project duration:

01.11.2019 - 31.10.2022

Project sponsor

Project partner

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