Amidation‐Dominated Re‐Assembly Strategy for Single‐Atom Design/Nano‐Engineering: Constructing Ni/S/C Nanotubes with Fast and Stable K‐Storage

An amidation‐dominated re‐assembly strategy is developed to prepare uniform single atom Ni/S/C nanotubes. In this re‐assembly process, a single‐atom design and nano‐structured engineering are realized simultaneously. Both the NiO₅ single‐atom active centers and nanotube framework endow the Ni/S/C ternary composite with accelerated reaction kinetics for potassium‐ion storage. Theoretical calculations and electrochemical studies prove that the atomically dispersed Ni could enhance the convention kinetics and decrease the decomposition energy barrier of the chemically‐absorbed small‐molecule sulfur in Ni/S/C nanotubes, thus lowering the electrode reaction overpotential and resistance remarkably. The mechanically stable nanotube framework could well accommodate the volume variation during potassiation/depotassiation process. As a result, a high K‐storage capacity of 608 mAh g^?1 at 100 mA g^?1 and stable cycling capacity of 330.6 mAh g^?1 at 1000 mA g^?1 after 500 cycles are achieved.