인천대학교 인디고클랫폼 인천대학교 기술지원허브

Although nickel-rich cathode materials have been suggested as prospective advanced cathodes for over 20 years, their poor cycling lifespan remains the main challenge in achieving stable cycling. Herein, we report the use of 4-(trifluoromethyl)phenyl isothiocyanate (FIC) as an efficient interface-forming additive for stabilizing the Ni-rich cathode interfaces. Because the FIC additive involves an isothiocyanate (NCS) functional group, it is predicted that the electrochemical oxidation of the FIC results in NCS-functionalized cathode–electrolyte interphases (CEI) at the interface of the nickel-rich cathode, which is expected to constrain parasitic reactions. According to the linear sweep voltammetry, the electrochemical oxidation of the FIC permits the build-up of NCS-functionalized CEI layers at 3.97 V (vs. Li/Li+) without severe intervening of Li+ transport during the electrochemical processes. In cycling performance, the FIC-containing electrolytes experienced a remarkable improvement in retention at high-temperature cycling (89.1%), whereas the baseline electrolyte led to an enormous fading of the retention (70.3%). Further systematic SEM, EIS, XPS, and ICP-MS analyses indicate that less electrolyte decomposition and irreversible dissolution of transition metals are found at the interface of recovered Ni-rich cathodes by the incorporation of NCS-functionalized CEI layers.