Reactive Fluids

Various battery materials can be produced in EMPI's synthesis facilities, which are tested both for their physicochemical material properties and their performance in battery cells. In addition to Li and Na solid electrolytes, we are particularly interested in silicon-based anode materials. The aim of our work on anode materials is to produce innovative, long-term stable storage materials with very high capacity that can be used in both classic Li-ion batteries and solid-state batteries. Amorphous compounds with the composition SiCx and SiNx have proven to be particularly suitable for this purpose. The anode materials we produce offer advantages in terms of capacity, stability and charging rates. In the field of solid electrolytes, we are particularly interested in materials from the NAtrium Super Ion CONductor (NASICON) compound class and various Li solid-state ion conductors (lithium lanthanum zirconate, LLZO, and lithium aluminium titanium phosphate, LATP). Due to their nanoscale size, solid electrolytes are characterised by low processing temperatures in the further manufacture of solid-state batteries and enable the production of metal oxide/polymer composite materials.

Battery production and characterisation

For the electrochemical evaluation of the anode materials, slurries are first produced from the nanopowders. To do this, they are mixed with suitable solvents in a centrifugal mixer (Thinky, ARE 250) until a thick, homogeneous paste is obtained. Typically, conductivity additives (usually carbon black) and binders (usually polyacrylic acid) are also added to the mixture. This paste is applied to a copper foil with a defined layer thickness. After drying, the homogeneity, adhesion and conductivity of the coating are checked. Punch-out electrodes are assembled into button cells or 3-electrode cells in an argon-filled glovebox together with metallic lithium and an electrolyte. These can be tested over hundreds of charge and discharge cycles using a 96-channel MACCOR battery tester. In addition, a 16-channel Biologic VMP-3 measuring device with impedance function is available for highly sensitive measurements. This allows not only the performance characteristics to be examined in detail, but also the mechanisms in the materials.

Literature:

M. Loewenich, J. Kondek, M.R. Hansen, H. Wiggers, Amorphous Sub‐Stoichiometric Silicon Carbide (a‐SiCx) Particles from the Gas Phase for Battery Applications, Battery Energy 4 (2025) e70048, DOI: 10.1002/bte2.20250041

S. Kilian, B. Wankmiller, A.M. Sybrecht, J. Twellmann, M.R. Hansen, H. Wiggers, Active Buffer Matrix in Nanoparticle-based Silicon-Rich Silicon Nitride Anodes Enables High Stability and Fast Charging of Lithium-Ion Batteries, Adv. Mater. Interfaces, 26 (2022) 2201389, DOI: 10.1002/admi.202201389

G.M. Overhoff, Md.Y. Ali, J.P. Brinkmann, P. Lennartz, H. Orthner, M. Hammad, H. Wiggers, M. Winter, G. Brunklaus, Ceramic-in-Polymer Hybrid Electrolytes with Enhanced Electrochemical Performance, ACS Appl. Mater. Interf., 14 (2022) 53636, DOI: 10.1021/acsami.2c13408

Md.Y. Ali, H. Orthner, H. Wiggers, Spray Flame Synthesis (SFS) of Lithium Lanthanum Zirconate (LLZO) Solid Electrolyte, Materials 14 (2021) 3472, DOI: 10.3390/ma14133472