Let us make a bit of history of what happened in the project…
By M0 we put our hands to work.
By M9 we defined the cell and material requirements. Varta Microbattery, Varta Storage , Bouyges, and VDL defined the cell requirements volumetric and gravimetric specific capacity requirements considering the stationary applications, being summarized in D.2.1 Use case and KPI definition.
Specific energy density of active materials
Volumetric energy density of active materials
By M15 Solvay, CEA, Topsoe, Torrecid and IFE were working on materials, anode, cathode GPE working on improving material capacity, compatibility with electrolytes .
LMNO single crystals 4 microns size were developed. Powder coating was implemented and reactor for scaling up installed.
Powder Si-G materials were optimized and insitu synthesis reactor built that allowed to fine tune the Si to G ratio and particle size, agglomeration. Synthesis conditions in reactor were optimized to obtain spherical particles. a material with a specific capacity for 1200 mah/gr was obtained.
In parallel TNO powder was optimized by CEA and Torrecid, in terms of cost-effective solid state synthesis studying different dopants. Dopants were studied in terms of cyclability and specific capacity. Crystallographic phase was also a target to keep crystalline phase.
Solvay took the developed powders and adjusted the gel binder and electrolyte to the materials for electrode and GPE separator. High boiling solvents were selected.
WP4 started building electrodes with active powders and tailored Gel binders. Rheology of the binder powder mixture was adjusted, solid content, addition and % of conductive additives calendaring pressure, adhesion, flexibility, water content were evaluated and electrolyte optimized . This work was done for each active material.
WP5 by CICenergigune provided the material characterization that allowed to improve materials by avoiding amorphization, leaching of metals using characterization technologies like XPS, ICP-OES, FTIR…
Important achievement is the higher thermal stability of the GPE.
By the time Cidetec and Solvay worked together in adjusting the GPE to the cathode and anode and as a result in M24 CID managed to set up FCC and MPC. Processing of the powders to scale up for larger cells involved evaluation of mixer conditions, adjusting of binder content depending on the powder chemistry influencing discharge capacity.
Qcharge / mAh.g-1
Qdischarge / mAh.g-1
In parallel to all these activities CoFBAT has developed a recycling concept to achieve target of 65% recycling.
And finally we are ready to start scaling up the 21700 cells by M26!