Regulating Graphitic Microcrystalline and Single‐Atom Chemistry in Hard Carbon Enables High‐Performance Potassium Storage

• Published in: Advanced functional materials Vol. 34; no. 12
• Main Authors: Xu, Wenbin, Li, Huaidong, Zhang, Xinyue, Chen, Tsung‐Yi, Yang, Hao, Min, Huihua, Shen, Xiaodong, Chen, Han‐Yi, Wang, Jin
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.03.2024
• Subjects: Carbon; catalytic pyrolysis; Density functional theory; Electron distribution; Electron transfer; hard carbon; Interlayers; Manganese ions; Potassium; potassium‐ion batteries; Pyrolysis; Rechargeable batteries; single‐atom
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202309509

Hard carbon (HC) has attracted considerable research interest as the most promising anode for potassium‐ion batteries (PIBs) due to its tunable interlayer spacing and abundant voids to accommodate K+. However, the practical application of hard carbon is severely hampered by low initial Coulombic efficiency (ICE) and high plateau potential. Herein, a manganese ion‐catalyzed pyrolysis strategy is explored to regulate the graphitic microcrystalline structure and localized electron distribution in hard carbon that greatly improve K+ plateau storage and ICE. Systematic experimental measurements, in situ/ex situ observations, dynamic analysis, and density functional theory calculations elucidate that the introduction of Mn2+ ions could catalyze the formation of short‐ordered graphitic nanodomains in hard carbon to provide abundant insertions of K+, and meanwhile induce localized electron distribution through the Mn─N3─C coordination structure to enable dynamic K+ diffusion and electron transfer kinetics. Consequently, the modulated hard carbon exhibits a high low‐potential–plateau capacity, excellent rate capability, and high initial Coulombic efficiency in potassium half‐cell configurations. More importantly, the charge storage mechanism of “adsorption–intercalation” is proposed based on the correlation between carbon structures and discharge/charge plateau. This work provides an in‐depth insight into the fundamentals of microstructure regulation of hard carbon anode for high‐performance PIBs. A manganese ion‐catalyzed pyrolysis strategy is explored to regulate the graphitic microcrystalline structure and localized electron distribution in hard carbon that greatly improve K+ plateau storage and initial Coulombic efficiency (ICE). The as‐prepared hard carbon anode possesses high low‐potential–plateau capacity, excellent rate capability, and high ICE for potassium ion half‐cells, as well as high energy/power density for potassium‐ion hybrid capacitors.