Imec Achieves 400Wh/Liter with Solid-State Li-Metal Battery

June 19, 2019 by Scott McMahan

Imec announced at the European Electric Vehicle Batteries Summit (Berlin, June 18-19) a solid-state Li-metal battery cell with an unsurpassed energy density of 400 Wh/liter at a charging speed of 0.5C (2 hours).

Imec also reported that they have begun to upscale the materials and processes in a pilot line for fabrication of solid-state pouch cells at the EnergyVille Campus in Genk (Belgium) and the pilot line is set-up in collaboration with the University of Hasselt.

With its engineering roadmap for solid-state batteries, Imec is targeting 1000Wh/L at 2-3C performance by 2024, surpassing wet Li-ion batteries.

Today's rechargeable Li-ion battery technology still has room for improvement, but this improvement is not enough to significantly increase e.g. the range and improve the autonomy of EVs. Therefore, Imec's researchers are attempting to replace the wet electrolyte with a solid material.

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This solid material battery offers a platform to further improve the energy density of the cell beyond that of liquid-electrolyte-based cells.

Pilot battery samples undergoing testing

The solid nanocomposite electrolyte that the R&D center developed boasts exceptionally high conductivity of up to 10 mS/cm with a potential for even higher conductivities.

Uniquely, the new material is applied as a liquid via wet chemical coating and only afterward is it converted into a solid when it is already in position in the electrodes. That way, imec says, it is well suited to be cast into dense powder electrodes where it fills all cavities and makes maximum contact, just as a liquid electrolyte does.

Using that solid nanocomposite electrolyte combined with a standard lithium iron phosphate (LFP) cathode and lithium metal anode, imec has now created an improved battery with an energy density of 400Wh/liter at a charging speed of 0.5C (2 hours), a record combination for a solid-state battery. With this performance result, imec managed to double its excellent outcome of last years efforts, following its roadmap to ultimately reach densities over 1,000Wh/liter at a charging speed of 2-3C (less than half an hour).

The newly started upscaling of the cells is taking place in a state-of-the-art lab for this new solid-state battery technology. The lab includes a 300 square meter battery assembly pilot line, which includes a dry room of 100 square meters.

The fabrication uses a conventional A4 sheet-to-sheet wet coating-based line which imec says is well suited for processing its innovative solid electrolyte. As such, the construction of the new cells could be done with slight modification of existing manufacturing lines for Li-ion batteries.

Therefore, the new technology would not need expensive investments to switch from wet to solid-state cells, imec says. The new pilot line and lab, which are located at the EnergyVille Campus, are set-up together with the University of Hasselt. The pilot line allows manufacturing of prototype pouch cells of up to 5Ah capacity, and the lab is ready to become a cornerstone for research groups and companies doing R&D projects on these batteries.

"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 processes similar to those for wet batteries," says Philippe Vereecken, Scientific Director at Imec/EnergyVille.

Imec notes that bringing innovative battery technology to fruition and transferring it to the market will require the involvement and commitment of major material suppliers and battery producers. For this reason, Imec performs its battery R&D as a collaborative effort, encouraging open innovation to which it invites all interested parties.