Polymer‐Based Solid‐State Electrolytes for High‐Energy‐Density Lithium‐Ion Batteries – Review

Portable electronic devices and electric vehicles have become indispensable in daily life and caused an increasing demand for high‐performance lithium‐ion batteries (LIBs) with high‐energy‐density. This work compares the intrinsic characteristics and Li⁺ conduction mechanisms of various electrolytes, aiming at emphasizing their suitability for high‐energy‐density LIBs. Among all electrolytes, polymer‐based solid‐state electrolytes (SSEs) are the most promising candidates, as they demonstrate the most comprehensive properties. The advantages and disadvantages of commonly used polymer matrix materials of SSEs are discussed, along with typical approaches to address their limitations. As significant issues for high‐energy‐density and cycle stability, the development related to the cathode/electrolyte interfacial contact and wetting, interfacial electrochemical compatibility, and interfacial Li⁺ conduction in LIBs employing polymer‐based SSEs, as well as the anode/electrolyte interfacial chemical stability and lithium dendrite suppression are comprehensively reviewed and analyzed. Finally, perspectives on future research directions for developing high‐energy‐density LIBs are highlighted building upon the existing literature.