For electric mobility and many other applications, Lithium-ion batteries with a high energy density and low costs are demanded. To promote both features on the part of the anodes, the use of carbon coated, abundant SiO (SiO-C) with its high specific capacity and good cycling stability as an active material is very promising.[1] However, SiO-C shows a high irreversible capacity loss in the initial formation cycle resulting in a low initial coulombic efficiency. This impairment can be effectively mitigated by applying pre-lithiated SiO-C particles (Li-SiO-C).[2,3]

For a stable industrial electrode production process, certain requirements have to be fulfilled by the slurries. However, research reported about the application of all kinds of SiO-C is mainly based on lab scale experiments. In this presentation, we illustrate the challenges and impairments occurring when Li-SiO-C is processed. Li-SiO-C particles cause a strong basicity in battery suspensions.[4] The created environment affects different chemical and physical properties of the suspensions which have a decisive influence on processability. The suspensions suffer from a low stability, cause filter clogging during application, defective coatings and poor adhesion of the electrode composite.

We explain an approach that enables a basic processability under common production conditions and with common equipment by the use of an additive. Moreover, we show that the use of single-walled carbon nanotubes (SWCNTs) as well as an appropriate binder are decisive strategies to further improve the processability of Li-SiO-C regarding the stability and shear thinning behaviour of the slurries and the adhesion strength of the electrodes. Our work is based on highly relevant LIB electrodes containing as much as 20 % pre-lithiated SiO in the anode active material and an active mass content of up to 96.75% in the electrode composite and it implies production in a pilot scale. By demonstrating a good electrochemical performance including a cycling stability over 500 cycles in full cells, we verify the suitability of our concepts.

References:
[1] M. Xia et al., „Scalable synthesis SiO@C anode by fluidization thermal chemical vapor deposition in fluidized bed reactor for high-energy lithium-ion battery“, Appl. Surf. Sci. 467–468 (2019), 298–308.
[2] T. Hirose et al., “Comparison of the Structure and Phase Changes of Carbon-Coated SiO and Li-Doped Carbon-Coated SiO During Repeated Charge–Discharge Cycling“, J. Electrochem. Soc., 167 (2020), 120523.
[3] Y. Reynier et al., “Practical implementation of Li doped SiO in high energy density 21700 cell.” J. Power Sources, 450 (2020) , 227699.
[4] Kuo, Chih-ying; Hsu, Hsiao-ping; Lan, Chung-wen, „Scalable chemical prelithiation of SiO/C anode material for lithium-ion batteries“, J. Power Sources, 558 (2023), 232599.

Acknowledgement:
The presented work was financially supported by BMBF within the project WaBaFli under the reference number 03XP0409D.