Exploring synergetic effects of vinylene carbonate and 1,3-propane sultone on LiNi0.6Mn0.2Co0.2O2/graphite cells with excellent high-temperature performance

LiNi0.6Mn0.2Co0.2O2 attracts increasing attention in industry due to its high energy density. Vinylene carbonate and 1,3-propane sultone are engaged to enhance the high-temperature performance of LiNi0.6Mn0.2Co0.2O2/artificial graphite pouch cells in this work. With the addition of the additives, the capacity retention of the full cell reaches 98% after 200 cycles at 45 °C and 500 mA. Meanwhile, the underneath mechanism is investigated by employing X-ray photoelectron spectroscopy, gas chromatograph-mass spectrometer and liquid chromatography-quadruple time of flight mass spectrometry measurements. The results show that the additives can not only protect the anode, but also shelter the cathode. It is of great interest that vinylene carbonate can suppress the decomposition of electrolyte, leading to less organic species in electrolyte, more stable interfaces. The addition of 1,3-propane sultone takes part in the generation of sulfonates after formation, which can be reduced to sulfides upon cycling. The combination of these two additives can optimize the interfacial reactions, as well as can suppress the decomposition of electrolytes and the dissolution of manganese, which leads to much better high-temperature storage performance and cycling performance of the full cells. [Display omitted] •VC and PS as electrolyte additives in NMC622/graphite cells are investigated.•Capacity retention is 98% after 200 cycles at 0.5 C and 45 °C with VC and PS.•The thicker CEI can prevent Mn dissolution more effectively.•Sulfonates on anode are reduced to sulfides upon cycling.