Scientists at the Chalmers University of Technology, Sweden, and Xi'an Jiaotong University, China, have developed an interlayer that boost the current density of a solid state battery tenfold.
The interlayer is made of a spreadable, 'butter-like' material, making it easier to integrate into a production process for an electric vehicle solid state battery while increasing performance and safety.
"This interlayer makes the battery cell significantly more stable, and therefore able to withstand much higher current density. What is also important is that it is very easy to apply the soft mass onto the lithium metal anode in the battery - like spreading butter on a sandwich," said Shizhao Xiong, a researcher at the Department of Physics at Chalmers.
In the solid state battery design, a layer of the metal lithium is combined with a layer of ceramic solid electrolyte, transports lithium ions between the electrodes of the battery. The spreadable interlayer is made of nanoparticles of the ceramic electrolyte, LAGP (Li 1.5Al0.5Ge1.5(PO4)3), mixed with an ionic liquid. The liquid encapsulates the LAGP particles and makes the interlayer soft and protective. The material, which has a similar texture to butter from the fridge, fills several functions and can be spread easily.
This creates a chemically stable interface between the metal and ceramic layers with low resistance of 5 Ω cm 2) and efficiently prevents thermal runaway at elevated temperatures of 300 °C. Solid‐state cells designed with the interlayer can be operated at high current densities, 1 mA/cm 2, and enable high rate capability with high safety.
"This is an important step on the road to being able to manufacture large-scale, cost-effective, safe and environmentally friendly batteries that deliver high capacity and can be charged and discharged at a high rate," said Aleksandar Matic, Professor at the Department of Physics at Chalmers,