Simultaneous Realization of Multilayer Interphases on a Ni-Rich NCM Cathode and a SiO_x Anode by the Combination of Vinylene Carbonate with Lithium Difluoro(oxalato)borate

Abstract

Ni-rich NCM and SiO x electrode materials have garnered the most attention for advanced lithium-ion batteries (LIBs); however, severe parasitic reactions occurring at their interfaces are critical bottlenecks in their widespread application. In this study, an effective additive combination (VL) composed of vinylene carbonate (VC) and lithium difluoro(oxalato)borate (LiDFOB) is proposed for both Ni-rich NCM and SiO x electrode materials. The LiDFOB additive individually delivers inorganic-rich cathode−electrolyte interphase (CEI) and solid−electrolyte interphase (SEI) layers in anodic and cathodic polarizations before the VC additive. Subsequently, the VC additive is capable of the formation of additional CEI and SEI layers composed of relatively organic-rich components through an electrochemical reaction; thus, inorganic−organic hybridized CEI and SEI layers are simultaneously formed at the Ni-rich NCM and SiO x electrodes. Accordingly, the VL-assisted electrolyte exhibits remarkably prolonged cycling retention for the Ni-rich NCM cathode (86.5%) and SiO x anode (72.7%), whereas the standard electrolyte shows a substantial decrease in cycling retention for the Ni-rich NCM cathode (59.2%) and SiO x anode (18.1%). Further systematic analyses prove that VL-assisted electrolytes form effective interphases for Nirich NCM and SiO x electrodes simultaneously, thereby leading to stable and prolonged cycling behaviors of LIBs that offer high energy densities.