插层(化学)
材料科学
石墨烯
石墨
钾
微观结构
化学工程
碱金属
固溶体
纳米技术
化学物理
无机化学
化学
复合材料
冶金
有机化学
工程类
作者
Jiae Um,Seung Uk Yoon,Hoseong Kim,Beom Sik Youn,Hyoung‐Joon Jin,Hyung‐Kyu Lim,Young Soo Yun
标识
DOI:10.1016/j.jechem.2021.11.027
摘要
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).
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