In this podcast i discuss the following points raised by Eveline from Delft University of Technology (original text):
In my group we do a lot of work with solid state inorganic electrolytes. I would be extremely interested in your view about the scale up and economics of such systems! For example, in your last Podcast you describe how the LPS/Polymer cells are made.
1. How could such processes be implement on a larger scale and for larger batteries?
2. And if two polymer interfaces are needed, what is the benefit compared to a composite polymer electrolyte with inorganic fillers?
3. And then, compared to standard lithium-ion, is it even possible that the technology could ever compete economically?
Hydro-Québec has been a leading solid polymer electrolyte (SPE) innovation engine for more than 20 years. It has already licensed legitimate solid battery technologies to electric car manufacturers such as Bluecar and Dongshi Kingpower. While initially limited to LFP cathodes and 80C operating temperature, current SPE technology extends to high voltage NCM, NCA or LCO cathodes and can operate at a lower temperature of 40C. SPE electrolytes are also stable with lithium metal electrodes guaranteeing higher energy densities than lithium ion cells with conventional liquid electrolytes.
Cycle life of solid state batteries with SPE is governed by the electrochemical stability of the polymer during cycling. Since most such polymers are crosslinked in order to improve their mechanical and electrochemical properties, residual crosslinking agent may often remain in the SPE during battery operation. This may cause undesired side reactions and accelerate deterioration of SPE. In this patent, Hydro-Québec discloses a crosslinking strategy which improves electrochemical stability.
Plating lithium metal anodes through inorganic solid electrolytes is challenging and slow due to proliferation of dendrites along the grain boundary where ionic conductivity is higher. Sakamoto’s group shares evidence of rate improvements without dendritic growth with LLZO solid electrolytes.