Monday, 30 May 2022: 15:20
West Meeting Room 109 (Vancouver Convention Center)
Batteries capable of fast charging rely on electrolytes that maximize ion mobility to allow redox reactions to proceed at the same rate electrons are transported between electrodes. Here I will describe our recent efforts in liquid electrolyte development to enable 80% change in state-of-charge in 15, 10, and 5 minutes in lithium metal batteries without irreversible damage to the cell. The effects of concentration, viscosity, ionic conductivity, and solvation effects on cycle life are investigated, revealing that electrolytes with the highest Li+ mobility minimize the fast-charge overpotential and enable the full capacity of the cell to cycle reversibly. We further show through detailed synchrotron hard X-ray microtomography and complementary scanning electron microscopy that such electrolytes also suppress ramified Li growth. We also perform detailed electroanalytical studies to quantify the remarkably slow rates of lithium consumption and point to dead lithium formation as a primary challenge for (ultra)-fast-charging lithium metal batteries.