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. Metal–organic framework (MOF) nanorod‐assembled superstructure is fabricated in a facile one‐pot synthesis by precise control of reaction temperature and time. Carbon nanorod‐assembled superstructure can be obtained using the MOF superstructure as precursor, which can serve as a high‐performance anode material for fast potassium storage with high specific capacity, high rate capability, and high long‐term cycling stability.