Electrostatic Interaction-directed Construction of Hierarchical Nanostructured Carbon Composite with Dual Electrical Conductive Networks for Zinc-ion Hybrid Capacitors with Ultrastability

Metal-organic framework (MOF)-derived carbon composites have been considered as the promising materials for energy storage. However, the construction of MOF-based composites with highly controllable mode via the liquid-liquid synthesis method has a great challenge because of the simultaneous heterogeneous nucleation on substrates and the self-nucleation of individual MOF nanocrystals in the liquid phase. Herein, we report a bidirectional electrostatic generated self-assembly strategy to achieve the precisely controlled coatings of single-layer nanoscale MOFs on a range of substrates, including carbon nanotubes (CNTs), graphene oxide (GO), MXene, layered double hydroxides (LDHs), MOFs, and SiO2. The obtained MOF-based nanostructured carbon composite exhibits the hierarchical porosity (V-meso/V-micro: 2.4), ultrahigh N content of 12.4 at.% and "dual electrical conductive networks." The assembled aqueous zinc-ion hybrid capacitor (ZIC) with the prepared nanocarbon composite as a cathode shows a high specific capacitance of 236 F g(-1) at 0.5 A g(-1), great rate performance of 98 F g(-1) at 100 A g(-1), and especially, an ultralong cycling stability up to 230 000 cycles with the capacitance retention of 90.1%. This work develops a repeatable and general method for the controlled construction of MOF coatings on various functional substrates and further fabricates carbon composites for ZICs with ultrastability.