Bridging Donor Ligands Enable an Ultrastable Graphite Anode for Sodium‐Ion Batteries

Abstract

Abstract Graphite is widely utilized as an anode material in lithium‐ion batteries due to its abundance, cost‐effectiveness, and excellent structural stability during lithium intercalation and deintercalation, which contribute to a long cycle life. However, graphite is not inherently suitable for sodium‐ion batteries (SIBs) due to the limited intercalation properties of sodium ions. To address this, we propose the concept of bridging‐donor‐ligands, which construct ligand channels and consistently expand the graphite interlayer spacing. Using sodium dicyandiamide (NaDCA) as a model ligand, we demonstrate the formation of abundant ligand channels facilitated by the versatile dicyanamide anion (DCA − ), significantly enhancing the structural robustness of ternary graphite intercalation compounds (t‐GICs). Hence, the graphite anode capacity retention is over 94% after 5000 cycles, with an average Coulombic efficiency (CE) exceeding 99.8% in SIBs. This mechanism is versatile and can be extended to other metal‐ion battery electrolytes.