Advances in host selection and interface regulation of polymer electrolytes

Abstract Polymer electrolyte (PE) has been emerging as a promising alternative to liquid electrolytes due to the unique advantages such as excellent flexibility and processability, high chemical and thermal stability, and low risk of leakage and combustion, especially for lithium‐ion batteries (LIBs). Even though abundant attempts focusing on polymer chemistries have been made, the inadequate capacity of lithium‐ion transport via segmental motion still cannot provide satisfying room temperature ionic conductivity and lithium‐ion transference number. In addition, safety concerns and short lifespan resulted from the brittle and incompatible interface between the electrode and polymer materials also hinder the commercialization of PEs‐based LIBs. Hence, for the above performance defects and interface issues, this review provides an overview of polymer electrolytes from the conductivity improvement, polymer selection and mechanical strength enhancement for protrusion suppressing. The improvement of conductivity specifically includes structure modification of poly(ethylene oxide) (PEO) host and novel electrolyte matrix beyond PEO, while the section of interface regulation mainly involves dendrite‐inhibited polymers, mechanical strengthening, and in situ polymerization. Finally, perspectives and challenges are pointed out in the development of polymer electrolytes with both excellent electrochemical performance and safety for LIBs.