Recent advances in high performance conducting solid polymer electrolytes for lithium-ion batteries

Lithium-ion batteries (LIBs) as an important energy storage technology have found more and more applications in electric vehicles, electronic devices as well as grid energy storage systems. However, due to the safety issues from the flammability of combustible organic liquid electrolytes, recently solid polymer electrolytes (SPEs) have attracted more interest. Conventional SPEs are dual-ion conductors where both anions and cations possess slightly free movement and favor the concentration polarization phenomena, which may reduce their performances and lifetime. To overcome these issues, the conducting solid polymer electrolytes (CSPEs) are developed where the anions are linked via covalent bonds to the polymeric and inorganic backbones or anion acceptors, which may greatly accelerate the transportation of lithium ions and increase their lithium-ion transference number (LTN) and ionic conductivity as well as reduce the formation of concentration polarization and Li dendrite growth. Herein, a comprehensive overview of the latest development in CSPEs for LIBs is described, which emphasizes the correlations among their synthetic strategies, structures, and electrochemical performances. Finally, the state of the art, future perspectives, and core challenges are provided for designing the next generation of CSPEs in high performance LIBs.