Realizing High‐Performance Li/Na‐Ion Half/Full Batteries via the Synergistic Coupling of Nano‐Iron Sulfide and S‐doped Graphene

Iron sulfide (FeS) anodes are plagued by severe irreversibility and volume changes that limit cycle performances. Here, a synergistically coupled hybrid composite, nanoengineered iron sulfide/S‐doped graphene aerogel, was developed as high‐capacity anode material for Li/Na‐ion half/full batteries. The rational coupling of in situ generated FeS nanocrystals and the S‐doped rGO aerogel matrix boosted the electronic conductivity, Li + /Na + diffusion kinetics, and accommodated the volume changes in FeS. This anode system exhibited excellent long‐term cyclability retaining high reversible capacities of 422 (1100 cycles) and 382 mAh g −1 (1600 cycles), respectively, for Li + and Na + storage at 5 A g −1 . Full batteries designed with this anode system exhibited 435 (FeS/srGOA||LiCoO 2 ) and 455 mAh g −1 (FeS/srGOA||Na 0.64 Co 0.1 Mn 0.9 O 2 ). The proposed low‐cost anode system is competent with the current Li‐ion battery technology and extends its utility for Na + storage.