Promoting Li+‐Solvents Desolvation by Engineering Nickel Single Atoms into Graphene Membrane toward Fast Sulfur Redox Kinetics

Lithium‐sulfur (Li‐S) batteries featuring high energy density are expected to be next‐generation energy storage devices, but are severely impeded by the suppressive Li+‐solvents desolvation process at the electrode/electrolyte interface. Herein, a novel electrochemical in‐situ doping coupled with self‐assembly strategy is proposed to fabricate the graphene membrane anchored by Ni single atoms (Ni‐SA‐G), aimed at promoting the dissociation kinetics of Li+‐solvents complex by combining electrocatalysis and nanochannel sieving effect. Theoretical simulation and in‐situ Raman spectroscopy characterizations revealed that the Ni‐O5 configuration within the Ni‐SA‐G membrane is capable of lowering the Li+‐solvent dissociation energy barrier and promoting free Li+ migration, thereby delivering the fast sulfur redox kinetics. In addition, taking advantage of the Ni‐SA‐G membrane with a special transport channel, the large‐sized solvent molecules and polysulfides were sieved and confined to a great degree. As a result, the Li‐S batteries with the Ni‐SA‐G as cathode front‐faces exhibit a high capacity of 1169 mAh g−1 with a good rate performance and outstanding long‐term cycling stability, where a capacity decay of only 0.024% per cycle after 700 cycles can be achieved. Furthermore, the cell with a sulfur loading of 4.78 mg cm−2 delivers a high areal capacity of 4.0 mAh cm−2 at 0.2 C.