The energy density of solid state battery technology is a key factor in the adoption of safer, high power batteries, and Imech is aiming to reach 1000Wh/L by 2024 for long-range electrical vehicles.
The lithium metal solid-state battery cell with a record energy density of 400 Wh/l has a charging speed of 0.5C, charging ie in two hours. The centre is also expanding its pilot line for fabrication of 5Ah solid-state pouch cells at the EnergyVille Campus in Genk, Belgium, in collaboration with the University of Hasselt.
The solid nanocomposite electrolyte developed at Imec has a high conductivity of up to 10 mS/cm with a potential for even higher conductivities. A distinguishing feature of the new material is that it is applied as a liquid – via wet chemical coating – and only afterwards converted into a solid when it is already in place in the electrodes. That way it is perfectly suited to be casted into dense powder electrodes where it fills all cavities and makes maximum contact, just as a liquid electrolyte does.
The solid nanocomposite electrolyte is combined with a standard lithium iron phosphate (LFP) cathode and lithium metal anode to create the 400Wh/l solid state battery cell. This is twice the energy density of a cell developed last year, and is part of the move to reach densities over 1,000Wh/liter at a charging speed of 2-3C, ie charging in less than half an hour.
The cells are being built on a 300 square meter battery assembly pilot line which includes a dry room of 100 square meters using conventional A4 sheet-to-sheet wet coating-based processing. As such, the assembly of the new cells could be done by slight modification of existing manufacturing lines for Li-ion batteries and means the new technology would not need expensive investments to switch from wet to solid-state cells.
“The new battery demonstrates that our breakthrough electrolyte can be integrated in performant batteries. The pilot-line allows us to take the next step and upscale the battery breakthrough to industrially relevant processes and formats, using manufacturing