Enhanced high-voltage cycling stability of Ni-rich LiNi0.8Co0.1Mn0.1O2 cathode coated with Li2O–2B2O3

Abstract LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) is considered one of the most competitive cathode materials for lithium-ion batteries for use in next-generation electric vehicles. However, the poor cycle stability of layered Ni-rich cathode materials at high voltages (>4.3 V) has hindered their commercial development. In this study, we evaluate the effects of lithium boron oxide (LBO) glass as a lithium-ion-conductive coating layer on the structure, morphology, and electrochemical properties of NCM811 at a high cutoff voltage of 4.5 V. We show that NCM811 coated with 0.3 wt% LBO exhibits improved cycling retention (82.1%) compared with bare NCM811 (50.8%) after 100 cycles at 1C. Electrochemical impedance spectra and scanning electron microscopy and transmission electron microscopy images after cycling reveal that the LBO-coating layer not only lowered the charge-transfer resistance between the electrode and electrolyte but also improved the structural stability during cycling.