Though lithium-ion batteries (LIBs) have seen a meteoric rise in worldwide deployment over the last decade, they should be further advanced in constant demand of higher rate capability and wider temperature adaptability. A solid electrolyte interphase (SEI) is the essential part of LIBs, determining the charge-discharge performance and degradation behavior. Herein, improvement of the SEI properties is achieved by regulating the electrochemical double layer structure with a nonsacrificial electrolyte additive, that is, lithium nonafluoro-1-butanesulfonate. The anion adsorption of the additive affects the decomposition behavior of other additive and solvent species, and the generated SEI at the graphite electrode becomes thinner and more uniform, leading to decreased impedance and finally resulting in improved energy efficiency, power capability, and fast charging performance of the graphite/NCM811 cell. Furthermore, the low-temperature cycleability at -20 °C is considerably enhanced with no dendritic Li metal deposition at the negative electrode surface. A mechanistic study on the interfacial phenomena and the effect is carried out by using various theoretical and experimental methods, such as density functional theory calculations, electrochemical quartz crystal microbalance, and transmission electron microscopy. Consequently, the approach of SEI modification with the nonsacrificial electrolyte additive can be one of the effective ways to advance LIB technology in future.
Keywords: anion adsorption; high rate capability; lithium-ion battery; low-temperature performance; nonsacrificial additive; solid electrolyte interphase.