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 15, 10, and 5 minute charging in lithium metal batteries without irreversible damage to the cell. The effects of concentration, viscosity, ionic conductivity, and ion coordination on cycle life are investigated, revealing that electrolytes with sufficient Li<sup>+</sup> mobility enable the full capacity of the cell to reversibly cycle under aggressive (ultra)-fast-charge conditions. Full cell overpotential rise is found to be a primary culprit for capacity fade, pointing to the generation of resistive interphases at high current densities, which increase area specific resistance (ASR). We also find that top performing electrolytes suppress ramified Li growth and slow Li consumption rates, suggesting that a tandem effect of active material loss and ASR growth leads to cell failure.

Designing liquid electrolytes for ultra-high fast-charge in lithium metal batteries with high-voltage cathodes

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ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.