Asymmetric Temperature Modulation for Extreme Fast Charging of Lithium-Ion Batteries

Adding a 200-mile range in 10 min, so-called extreme fast charging (XFC), is the key to mainstream adoption of battery electric vehicles (BEVs). Here, we present an asymmetric temperature modulation (ATM) method that, on one hand, charges a Li-ion cell at an elevated temperature of 60°C to eliminate Li plating and, on the other, limits the exposure time at 60°C to only ∼10 min per cycle, or 0.1% of the lifetime of a BEV, to prevent severe solid-electrolyte-interphase growth. The asymmetric temperature between charge and discharge opens a new path to enhance kinetics and transport during charging while still achieving long life. We show that a 9.5-Ah 170-Wh/kg cell sustained 1,700 XFC cycles (6 C charge to 80% state of charge) at 20% capacity loss with the ATM, compared to 60 cycles for a control cell, and that a 209-Wh/kg BEV cell retained 91.7% capacity after 2,500 XFC cycles. [Display omitted] •Asymmetric charge and discharge temperatures enable durable extreme fast charging•High-temperature charging eliminates Li plating by enhanced transport and kinetics•Limited exposure time to high temperature avoids severe SEI growth•Elevated charging temperature reduces battery cooling need by >12× Electric vehicles will only be truly competitive when they can be charged as fast as refilling a gas tank. The US Department of Energy has set a goal of developing extreme fast charging (XFC) technology that can add 200 miles of driving range in 10 min. A critical barrier to XFC is Li plating, which usually occurs at high charge rates and drastically deteriorates battery life and safety. Here, we present an asymmetric temperature modulation (ATM) method that charges a Li-ion cell at an elevated temperature of 60°C to eliminate Li plating and limits the exposure time to 60°C to only ∼10 min per cycle to prevent serious materials degradation. Using industrially available battery materials, we show that a high-energy (209 Wh/kg) Li-ion cell with the ATM method retains 91.7% capacity after 2,500 XFC cycles (equal to 500,000 miles of driving range), far exceeding the US Department of Energy (DOE) target (500 cycles at 20% loss). An asymmetric temperature modulation method is presented in which a Li-ion cell is rapidly pre-heated to and charged at ∼60°C, and the cell’s exposure time to 60°C is limited to ∼10 min per cycle. The elevated temperature enhances kinetics and transport and hence eliminates Li plating; the limited exposure time to 60°C avoids severe materials degradat