Nitrogen‐Doped Carbon Nanotubes Derived from Metal–Organic Frameworks for Potassium‐Ion Battery Anodes

To tackle the issue of the poor rate capability of graphite anodes for potassium‐ion batteries (KIBs), nitrogen‐doped carbon nanotubes (NCNTs) with an edge‐open layer‐alignment structure were synthesized using a simple and scalable approach of pyrolyzing cobalt‐containing metal–organic frameworks. The unique structure enables a facile and fast intercalation of K ions. As anodes of KIBs, the NCNTs demonstrated an improved rate capability by a high capacity retention of 102 mA h g−1 at a high current density of 2000 mA g−1 and a good stability without evident capacity loss over 500 cycles at 2000 mA g−1. Our findings can help to develop highperformance anode materials for potassium‐ion batteries as large‐scale and low‐cost energy‐storage systems.