Carbon anode from carbon dots-regulated polypyrrole for enhanced potassium storage

Aiming at the problems of poor cycle stability of carbon-based materials in potassium ion batteries, functionalized nitrogen and sulfur co-doped carbon dots (CDs) are applied to improve the potassium sto-rage performance of electrode materials. In this work, the functionalized CDs are used to regulate the structure and morphology of the polypyrrole in-situ during the polymerization process of pyrrole monomer. Concretely, the original strip-like fibrous polypyrrole can be induced to become bead-like particle with the disappearance of fiber shape, and with the increase of the amount of carbon dots, the active particles increased. Compared with pure polypyrrole derived carbon, the carbon-dot-regulated polypyrrole derived carbon exhibits more excellent cycling performances with a shorter ion transmission and transfer path, more active sites, increased contact area with the electrolyte and improved structural stability. The specific capacity of the carbon anode carbonized from polypyrrole (C-ppy-NSCDs-10 0) regulated by 100 mg of carbon dots could reach 360.2 mAh g-1 at 0.1 A g-1, showing the application potential of carbon dots in improving electrochemical potassium storage by regulating the morphology of carbon-based materials. Predictably, these unparalleled features of CDs can be expected to inspire more exciting results in po-tassium-ion energy storage systems. (c) 2023 Elsevier B.V. All rights reserved.