Joanna Burdynska1
Factorial Energy1
As vehicle electrification advances, the need for high-energy, high-power energy storage solutions increases. The lithium-ion battery (LIB) has emerged as the technology of choice to meet these challenges. Nonetheless, with the ever-increasing battery capacity of cars to increase range, future systems will need to have significantly higher energy densities. At the same time, consumers are pushing for faster charging times [1].<br/>Future lithium-ion batteries may not be able to meet these requirements, especially since their energy density is limited by the given electrode configuration, in particular by the graphite anode. On top of this, safety concerns arise for such high energy systems, as the liquid, organic electrolyte is potentially flammable. To counter such concerns, next generation batteries are intended to employ solid or semi-solid electrolytes (SEs). Those novel electrolytes possess higher thermal stability, thus increase safety, and reduce leakage in the event of fire or crash.<br/>At the same time, those novel electrolytes are intended to allow substitution of the conventional graphite anode with a lithium metal anode. Elemental lithium being light-weight and possessing the most negative electrode potential is the ideal anode material choice and considered the holy grail of batteries. The use of lithium metal would significantly increase the cell energy density and allow electric vehicles to further increase their driving range, while simultaneously allow for faster charging times.<br/>As the prerequisite technologies for the practical solid-state batteries (SSBs) are reported and developed at quicker pace, its commercialization looks very promising. However, there are still problems to be solved.<br/>Highly conductive SEs, high voltage compatible cathodes and high-capacity anodes are good examples of these, however, they still must be verified by applying them to practically large format cells. At the same time, all these components of ASSBs should satisfy requirements of not only the high performance of each material, but also the compatibility between materials, mass production processability, and overall cost.<br/>Along with the cell design-related technology, multi-stacking and cell size upscaling is also crucial. Developed materials and cell technologies must be suitable for mass production not only in terms of materials, but also cells. In general, SSBs using inorganic SEs are more difficult for mass production rather than SSBs using polymer-based and/or semi-solid electrolytes.<br/>Factorial Energy is a leader in the field of semi-solid electrolytes. Prototype cells employing the proprietary Factorial Electrolyte System Technology (FEST<sup>TM</sup>) have demonstrated over 550 cycles when using a state-of-the-art nickel-rich cathode material and a lithium metal anode. Importantly, due to the semi-solid nature of the electrolyte, the cells have shown to perform well at ambient conditions, unlike other solid-state batteries, which require elevated temperatures to operate. After demonstrating the of high performance of semi-solid-state electrolytes Factorial Energy entered into development programs with three major OEMs, Mercedes Benz, Stellantis and Hyundai Motor Corporation. We believe that deep collaboration between battery companies and OEMs will help to accelerate the commercialization of next generation batteries.<br/>The successful commercialization of SSBs strongly relies on the development of the key technologies of its constituents (SEs having high ionic conductivity with high cathodic/anodic stabilities, cathodes having high specific capacity and stable to high oxidation potential, protected thin lithium metals). Also, it should come with the advanced processing including the techniques for upscaling, and cell optimization (i.e. chemical/electrochemical reactivity minimization and interfacial bonding control at the interfaces).<br/>References<br/>[1] J. Janek, Wolfgang G. Zeier, Nature Energy. 1, 16141 (2016)