Extreme Fast-Charging of Lithium-Ion Cells: Effect on Anode and Electrolyte

Herein, the effects of charge rate in coin cells containing NMC532/1506-T graphite are investigated. The cells are cycled at room temperature using charge rates of 1-, 2-, 4-, and 8-C and discharged at the 1-C rate for 50 cycles. The amounts of lithium and LiF are found to be highly correlated with charge time. Three decomposition products are identified in the organic electrolyte. The proposed, empirical formulae for these compounds are C14H33O15P3, C16H37O15P3, and C11H22O7PF; all are most likely organophosphates formed by the reaction of organic electrolyte decomposition products with LiPF6 or P(=O)F-3. The relative concentrations of these organics do not display sensitivity to charge rate. These results imply that a new performance fade mechanism is not introduced by electrolyte decomposition.

Automated summary

The effects of charge rate on coin cells containing NMC532/1506-T graphite were studied, showing that the amounts of lithium and LiF were highly correlated with charge time. Three decomposition products were identified in the organic electrolyte, with their relative concentrations not showing sensitivity to charge rate, implying that a new performance fade mechanism is not introduced by electrolyte decomposition.