Effect of Electrolyte Additives on Cycling Performance of 18650 Graphite//NMC811 Li-ion Batteries

Abstract

The practical application of Nickel-rich NMC811lithium-ion battery cylindrical cell type 18650 has been limited with its poor cycling stability due to transition metal dissolution, microcrack of NMC811 cathode, and thermodynamic instability of graphite anode. Herein, we study the effect of each electrolyte additive; VC, VEC, FEC, and PS, on the stability performance of the battery by varying the additive content at 1%, 2% and 3%. The study revealed the effect of electrolyte additives on the creation of stable SEI and CEI layers, which efficiently protected the surface of anode and cathode, respectively. It was found that high capacity retention of 61.98% can be obtained after 70 cycles, when 3%wt of VC, VEC, FEC, and PS was added. The average degradation rate of 0.54% per cycle was also observed. The improvement of cycling performance of the battery is confirmed.