Graphite Cone/Disc Anodes as Alternative to Hard Carbons for Na/K‐Ion Batteries

Abstract As sodium‐ion batteries compete for dominance in the energy storage market, the problem arises when using traditional graphitic anodes. Graphitic anodes used in Li‐ion batteries do not work well due to the limitation of Na‐ion diffusion and intercalation into graphite lattice. It is demonstrated that graphitic carbon cones and disks, manufactured via the scalable pyrolysis of hydrocarbons, are viable anode candidates for Na‐ion and K‐ion batteries. These distinctive pure graphitic carbon structures, without any heteroatoms present, show excellent Na‐ion intercalation, exhibiting a reversible capacity of ≈230 mAh g −1 at a current rate of 20 mA g −1 and excellent rate performance. The electrode has also been shown to exhibit excellent performance in K‐ion intercalation. Ex situ TEM analysis (at room and cryo temperatures) and solid‐state NMR spectroscopy show intercalated sodium and potassium evidence, revealing the charge storage mechanism. These pure graphitic structures can be a potential anode candidates for the next generation of beyond‐lithium batteries due to their morphologies that allow for reversible intercalation of larger ions without structural modifications.