General and Scalable Fabrication of Core-Shell Metal Sulfides@C Anchored on 3D N-Doped Foam toward Flexible Sodium Ion Batteries

Flexible self-standing transitional metal sulfides (TMSs)/carbon nanoarchitectures have attracted widespread research interests for sodium ion batteries (SIBs), thanks to their enormous capability to address intrinsic issues of TMSs for SIBs applications. However, controllable synthesis of hierarchical hybrid structures is always laborious and involves complicated procedures. Herein, a simple yet general and scalable adsorption-annealing strategy is first devised to finely construct core-shell carbon-coated TMSs (TMSs@C, including Co9S8@C, FeS@C, Ni3S2@C, MnS@C, and ZnS@C) nanoparticles anchored on 3D N-doped carbon foam (3DNCF) via the coordination and hydrogen-bond adsorption. Benefiting from synergistic contributions from strong chemical affinity between nanodimensional TMSs and 3DNCF, efficient electronic/ionic transport channels, as well as a uniform carbon accommodating layer, the resulted self-standing TMSs@C/3DNCF electrodes exhibit distinguished sodium storage performances, including large reversible capacities, high rate behaviors, and exceptional long-span cycle stability in both half cells and flexible full devices. More significantly, the smart methodology developed holds huge promise for commercialization of binder-free TMSs@C/3DNCF anodes toward advanced flexible SIBs.