Unraveling the Intercorrelation Between Micro/Mesopores and K Migration Behavior in Hard Carbon. Issue 12 (27th January 2022)

• Record Type: Journal Article
• Authors: Yuan, Fei; Zhang, Di; Li, Zhaojin; Sun, Huilan; Yu, Qiyao; Wang, Qiujun; Zhang, Jianguo; Wu, Yusheng; Xi, Kai; Wang, Bo
• Is Part Of: Small. Volume 18:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-27
• Subjects: anodes -- hard carbons -- micro/mesopores -- potassium migration behavior -- potassium ion batteries; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202107113
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Pore‐structure design with increased ion‐diffusion ability is usually regarded as an effective strategy to improve K‐storage performance in hard carbon (HC). However, the relationship between porous structure and K + migration behavior remains unclear and requires further exploration. Herein, a series of chemically activated hard carbon spheres (denoted as AHCSs) with controllable micro/mesopores structure are successfully synthesized to explore intercorrelation between micro/mesopores and K migration behavior. The experimental results indicate AHCSs have two different K + storage ways, that is, adsorption behavior at high potential region and intercalation process at low potential region. These behaviors are closely related to the pores structure evolution: the micropores afford extra active sites for efficient K‐ions adsorption, and therefore positive correlation between micropores and adsorption‐contributed capacity is confirmed; the mesopores permit more K‐ions intercalation/deintercalation by offering adequate pathways, and as a result positive correlations between mesopores and intercalation‐contributed capacity as well as initial Coulombic efficiency are revealed. All these together contribute to achieving excellent reversible capacity, and exceptional rate capability with an ultra‐long cycle lifespan in PIBs, and simultaneously exhibit a high energy density as well as considerable cycling stability for potassium‐ion full cells. These results promote a fundamental understanding of K + migration behaviors in hard carbon. Abstract : The intercorrelation between micro/mesopores and K migration behavior in hard carbon is revealed, in which the micropores afford extra active sites for efficient K‐ions adsorption; the mesopores permit more K‐ions intercalation–deintercalation by offering adequate pathways. Therefore, the sample with the optimal micro/mesopores configurations achieves an excellent electrochemical performance in terms of cycle and reversible capacity.