Improving cyclic stability of lithium nickel manganese oxide cathode for high voltage lithium ion battery by modifying electrode/electrolyte interface with electrolyte additive

Highlights: • Cyclic stability of LiNi_0.5Mn_1.5O₄ is improved significantly by using PES as additive. • A protective SEI is formed on LiNi_0.5Mn_1.5O₄ due to the preferential oxidation of PES. • The SEI suppresses electrolyte decomposition and structure destruction of LiNi_0.5Mn_1.5O₄. - Abstract: We report a new approach to improve the cyclic stability of lithium nickel manganese oxide (LiNi_0.5Mn_1.5O₄) cathode, in which the cathode/electrolyte interface is modified by using prop-1-ene-1, 3-sultone (PES) as an electrolyte additive. The interfacial properties of LiNi_0.5Mn_1.5O₄ cathode in PES-containing electrolyte have been investigated by scanning electron spectroscopy (SEM), transmission electron microscopy (TEM), thermal gravimetry (TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), cyclic voltammometry (CV), chronoamperometry (CA), and constant current charge/discharge test. It is found that the application of PES improves significantly the cyclic stability of LiNi_0.5Mn_1.5O₄. After 400 cycles at 1C rate (1C=147 mA g⁻¹), the capacity retention of LiNi_0.5Mn_1.5O₄ is 90% for the cell using 1.0 wt% PES, while only 49% for the cell without the additive. The characterizations from SEM, TEM, TG, XRD, and XPS confirm that the LiNi_0.5Mn_1.5O₄/electrolyte interface is modified and a protective solid electrolyte interface film is formed on LiNi_0.5Mn_1.5O₄ particles, which prevents LiNi_0.5Mn_1.5O₄ from destruction and suppresses the electrolyte decomposition