High-energy-density fiber-shaped aqueous Ni//Fe battery enabled by metal-organic framework derived spindle-like carbon incorporated iron disulfide

Metal dichalcogenides are regarded as encouraging electrode materials for aqueous rechargeable batteries on account of their excellent conductivity and theoretical capacity. Nevertheless, the structure's instability and low conductivity have restricted their development. Herein, MIL-101-Fe-derived spindle-like carbon incorporated FeS2 are successfully prepared exactly grown on carbon nanotube fibers (S–FeS2/CNTFs) with significantly enhanced conductivity and structure's stability due to the introducing of sulfur. Furthermore, we successfully constructed an outstanding-capacity fiber-shaped aqueous rechargeable (FAR) Ni//Fe batteries using the S–FeS2/CNTFs as advanced anodes. Density functional theory reveals that the S-doping significantly increase the conductivity and accomplish the structural reconstruction of the MIL-101-Fe. The S–FeS2/CNTF electrode exhibits a distinguished capacity of 0.55 mAh cm−2 at a current density of 6 mA cm−2, and maintains a capacity of 0.42 mAh cm−2 at a high current density of 200 mA cm−2, signifying outstanding rate performance. Notably, the as-assembled FAR Ni//Fe batteries achieve a phenomenal energy density of 137.5 mW h cm−3 at power density of 2200 mW cm−3. This approach affords an innovative opinion for developing outstanding-performance flexible aqueous energy-storage devices.