Constructing Robust Electrode/Electrolyte Interphases for Highly Stable Lithium–Sulfurized Polyacrylonitrile Batteries

Lithium–sulfurized polyacrylonitrile (SPAN) batteries show great promise for energy storage, but are plagued by poor cycling stability, which can be attributed to unfavorable electrode/electrolyte interphases for both anode and cathode. Here we design and achieve the anion‐moderate solvation structure based interconnected clusters in electrolyte by regulating the interactions of solvent with Li+ and diluent to construct robust anode/electrolyte and cathode/electrolyte interphases simultaneously for high‐performance Li–SPAN batteries. The optimal electrolyte endows Li plating/stripping with a high Coulombic efficiency of 99.47% at 1 mA cm–2 in Li||Cu cells. The Li–SPAN batteries show excellent cycling stability with a high capacity retention of 94.21% after 1215 cycles. Moreover, the assembled pouch‐type Li–SPAN battery under limited electrolyte condition (2.40 g Ah–1) achieves a capacity of 3.75 Ah, corresponding to a high energy density of 180 Wh kg–1 based on the total mass of the battery. This work provides a good electrolyte design principle to construct robust anode/electrolyte and cathode/electrolyte interphases for batteries.