A high‐safety, flame‐retardant cellulose‐based separator with encapsulation structure for lithium‐ion battery

The safety issues of lithium-ion batteries have received attention because flammable organic electrolytes are used. Also, the commercial polyolefin separator will undergo severe thermal shrinkage when internal temperature battery increases to 130–160°C, which risk. Therefore, development a high stability and high-safety is an effective strategy improve safety. Herein, we design green, cellulose-based (Cel@DBDPE) with unique encapsulation structure for batteries, in functional flame retardants (DBDPE) wrapped microscrolls formed by self-rolling 2D cellulose nanosheets upon freeze-drying. This can firmly anchor DBDPE particles prevent them from undergoing exfoliation does not affect properties separator, such as thickness pore structure. Compared polypropylene, Cel@DBDPE has excellent retardancy. former makes it less prone latter effectively combustion electrolyte, showing efficient self-extinguishing ability. Moreover, only 15 μm size competitive comparable polypropylene. Thus, there no sacrifice electrochemical performance used separator. study provides new structural construction