A Metal–Organic Framework Nanorod‐Assembled Superstructure and Its Derivative: Unraveling the Fast Potassium Storage Mechanism in Nitrogen‐Modified Micropores

3D carbon-based materials with multiscale hierarchy are promising electrode materials for electrochemical energy storage and conversion applications, but the synthesis in an efficient and large-scale way is still a great challenge. Herein, a carbon nanorod-assembled 3D superstructure is facilely fabricated by morphology-preserving conversion of a metal-organic framework (MOF) nanorod-assembled superstructure. The MOF superstructure can be fabricated in one-pot synthesis with high reproducibility and high yield by precise control of the MOF nucleation and growth. Its derived carbon inherits the nanorod-assembled superstructure and possesses abundant micropores and nitrogen doping, which can serve as a high-performance anode material for fast potassium storage. The superiority of the superstructure and the synergism of micropore capturing and nitrogen anchoring are verified both experimentally and theoretically.