Electrifying our transportation is one key step to decrease human society’s fossil fuel consumption, therefore, reducing CO₂ emissions. In the past decade, electric vehicles (EVs), especially electric passenger cars, are successfully commercialized and are gaining increasing market shares. Most of these EVs are powered by Li-ion batteries (LiBs) due to their high performance over other alternative vehicle power sources. After three decades of development, the energy density of LiBs has steadily increased to >250 Wh/kg at the cell level, which enables EVs with a comparable drive range to their gasoline counterparts. However, the charging time of LiBs is much longer than the refueling of a gasoline tank. The current battery technology can only achieve 80% charge for >30-40 minutes at a high temperature (40-50°C), which falls short of the U.S. Department of Energy (DOE)’s target of 80% charge within 10 minutes. Achieving such a super-fast charging performance without degrading battery life is a challenge that still has not been solved.

In this talk, I will discuss our latest findings that by engineering the composition of the electrolyte, the charging performance of LiB can be significantly enhanced. When compared with the commercial carbonate electrolytes (1M LiPF₆ in EC-DMC, LP30; or 1M LiPF₆ in EC-EMC, LP50), our electrolytes show remarkably better charging performance at all charging rate > 1C. Some formulation of our electrolyte is able to deliver >80% charge at 4C rate within 15 minutes at room temperature. I will discuss our fundamental study to understand the mechanisms underlying the remarkable charging performance of our electrolytes compared to the commercial carbonate electrolytes.