Sulfonylimide based single lithium-ion conducting polymer electrolytes boosting high-safety and high-energy-density lithium batteries

Single-ion conducting polymer electrolytes (SICPEs) have received much attention due to their excellent Li⁺ transference numbers, which can effectively reduce the concentration gradient and inhibit the growth of lithium dendrites. Recently, sulfonimide based SICPEs with superior ionic conductivity have become the most widely studied SICPEs by virtue of their highly delocalized anions and diverse molecular designability. In this review, the molecular design of sulfonimide based SICPEs is summarized in terms of anionic groups and polymer backbones of SICPEs. Then, the potential influence of SICPEs on battery safety is discussed from electrolyte level and interface level, respectively. It is believed that the battery safety and interface compatibility need to be given sufficient attention for SICPEs, in addition to the ion conductivity and Li⁺ transference number. It is hoped that this review can inspire a deeper consideration on SICPEs, which can pave a new pathway for the high-safety and high-energy-density lithium batteries.