The explosive expansion of the digital era and the rapid consumption of traditional energy such as fossil fuels have made lithium-ion batteries (LIBs) indispensable in our future. Battery applications are rapidly expanding from small 3C electronic devices to large power equipment fields such as pure electric vehicles, large energy storage, and pure electric aircraft. [1][2][3] Because of its characteristics of high energy density, high power density, and low selfdischarge rate, [2] in recent years, largecapacity and high-specific-energy LIBs have developed rapidly. However, as the energy density and power density grow, battery safety becomes more prominent. The operational temperature range of LIBs is narrow, and [4] when LIBs are subjected to conditions outside of their design window, they may fail through a rapid self-heating or thermal runaway, which may ignite the surrounding materials. [5] Several incidents involving LIBs have been reported over the last couple of years. [6,7] This is mainly because the current commercial separators mostly use polypropylene (PP) and polyethylene (PE) as the matrix of the polyolefin microporous membrane; its low melting point and softening temperature make the battery prone to thermal runaway caused by the disintegration of separators. Therefore, to solve the safety problem of LIBs, it is urgent to develop a new type of LIB separator with excellent thermal stability, outstanding flame retardant property, and excellent electrolyte wettability.The separator can prevent contact between the anode and cathode, playing an important role in battery safety. Currently, most commercial LIBs separators are polyolefin microporous separators, such as including PE and PP. [8] Those separators have many advantages such as good mechanical strength, excellent electrochemical stability, and sufficient chemical stability. However, they also suffer from many drawbacks, low ion conductivity, poor compatibility with electrolytes, and extensive shrinkage especially at high temperatures. [5,[9][10][11][12] Therefore, various approaches have been adopted to overcome those drawbacks.