Recent Advances in Electrolytes for High-Voltage Cathodes of Lithium-Ion Batteries

With the increasing scale of energy storage, it is urgently demanding for further advancements on battery technologies in terms of energy density, cost, cycle life and safety. The development of lithium-ion batteries (LIBs) not only relies on electrodes, but also the functional electrolyte systems to achieve controllable formation of solid electrolyte interphase and high ionic conductivity. In order to satisfy the needs of higher energy density, high-voltage (> 4.3 V) cathodes such as Li-rich layered compounds, olivine LiNiPO 4 , spinel LiNi 0.5 Mn 1.5 O 4 have been extensively studied. However, high-voltage cathode-based LIBs fade rapidly mainly owing to the anodic decomposition of electrolytes, gradually thickening of interfacial passivation layer and vast irreversible capacity loss, hence encountering huge obstacle toward practical applications. To tackle this roadblock, substantial progress has been made toward oxidation-resistant electrolytes to block its side reaction with high-voltage cathodes. In this review, we discuss degradation mechanisms of electrolytes at electrolyte/cathode interface and ideal requirements of electrolytes for high-voltage cathode, as well as summarize recent advances of oxidation-resistant electrolyte optimization mainly from solvents and additives. With these insights, it is anticipated that development of liquid electrolyte tolerable to high-voltage cathode will boost the large-scale practical applications of high-voltage cathode-based LIBs.