High-performance solid-solution potassium-ion intercalation mechanism of multilayered turbostratic graphene nanosheets

• Published in: Journal of energy chemistry Vol. 67; pp. 814 - 823
• Main Authors: Um, Jiae, Yoon, Seung Uk, Kim, Hoseong, Youn, Beom Sik, Jin, Hyoung-Joon, Lim, Hyung-Kyu, Yun, Young Soo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2022
• Subjects: Anode; Defective carbon; Graphene nanosheet; Potassium-ion batteries; Turbostratic graphite; Turbostratic graphite; Graphene nanosheet; Anode; Defective carbon; Potassium-ion batteries
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2021.11.027

[Display omitted] The solid-solution reaction between an alkali cation and an active host material is known as a single-phase redox mechanism, and it is typically accompanied by a continuous voltage change. It is distinct from the typical alkali cation intercalation reaction at an equivalent site of the active host material, which exhibits a voltage plateau. Herein, we report an unusual solid-solution potassium-ion intercalation mechanism with a low-voltage plateau capacity on multilayered turbostratic graphene nanosheets (T-GNSs). Despite the disordered graphitic structure with a broad range of d-spacings (3.65–4.18 Å), the T-GNSs showed a reversible plateau capacity of ∼ 200 mA h g−1, which is higher than that of a well-ordered graphite nanoplate (∼120 mA h g−1). In addition, a sloping capacity of ∼ 220 mA h g−1 was delivered with the plateau capacity, and higher rate capabilities, better reversibility, and a more stable cycling performance were confirmed on the turbostratic microstructure. First-principles calculations suggest that the multitudinous lattice domains of the T-GNSs contain diverse intercalation sites with strong binding energies, which could be the origin of the high-performance solid-solution potassium-ion intercalation behavior when the turbostratic graphene stacks have a d-spacing smaller than that of equilibrium potassium–graphite intercalation compounds (5.35 Å).