Synergistically optimizing electronic structure and reducing ions transport resistance by oxygen functional groups and defects in carbon for superior sodium capture and potassium storage capability

Abstract Electrochemical potassium storage and sodium capture play a critical role in supercapacitors (SCs) and capacitive deionization (CDI). Here, we report that a synergy of oxygen functional groups and intrinsic defects can boost potassium storage and sodium capture. The ions adsorption and migration can be easily tuned by manipulating oxygen functional groups and intrinsic defects. Compared to non-template carbon material, the Defects/Oxygen-containing functional groups modified carbon material presents an approximately 20% and 28.6% improvement in K+ transmission capability and Na+ storage capacity at similar conditions, respectively. Theoretical calculations further clarify that intrinsic defects redistribute electronic configuration, increase active sites and ion adsorption capability, oxygen functional groups promote the formation of more edge-defect, enlarge interlayer space and lower ion intercalation energy, thereby synergistically promoting sodium capture and potassium storage.