PNNL

Abstract

The purpose of the proposed project is to improve the performances of Farasis’ commercial high-energy lithium ion batteries in a wide temperature range. PNNL has developed intellectual property about electrolyte additives and electrolyte formulations to greatly improve the low temperature discharge performance and the long-term cycling stability at room temperature and elevated temperatures of lithium ion batteries. The graphite|| NCA (LiNi0.80Co0.15Al0.05O2) coin cells of 4 mAh size with the PNNL electrolyte can retain 60% of their room-temperature capacity when discharged at ?40?C, which is much higher than the cells using the conventional electrolyte which can retain only 18% of the capacity measured at room temperature. Such cells also show higher capacity retention and better cycling stability than cells with conventional electrolytes at elevated temperatures such as 60?C. The 1 Ah graphite||NMC (LiNi1/3Mn1/3Co1/3O2) pouch cells can also retain about 69% of the room-temperature capacity at ?40?C. However, these good results are based on small size cells (?1 Ah) and the electrode loadings are about 1.5 mAh/cm2 areal capacities, which are smaller than the commercial cell sizes (10-30 Ah) and the practical electrode loadings (? 3 mAh/cm2). Therefore, this project will allow both PNNL and the industry partner Farasis Energy, Inc. to work closely to develop and optimize the current PNNL electrolyte formulations to expand the temperature application range in Farasis’ high-energy lithium ion batteries. The benefits will be obvious to both parties if the project is successfully completed. The industry partner will achieve improved cell technology performance and can increase the sales of their battery products and also gain more profits. PNNL can also get benefits by licensing the electrolyte technology and gaining reputation in the battery industry.