Unraveling the Intercorrelation Between Micro/Mesopores and K Migration Behavior in Hard Carbon

Fei Yuan, Di Zhang, Zhaojin Li, Huilan Sun, Qiyao Yu*, Qiujun Wang, Jianguo Zhang, Yusheng Wu, Kai Xi, Bo Wang*

*Corresponding author for this work

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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.

Original languageEnglish
Article number2107113
JournalSmall
Volume18
Issue number12
DOIs
Publication statusPublished - 24 Mar 2022

Keywords

  • anodes
  • hard carbons
  • micro/mesopores
  • potassium ion batteries
  • potassium migration behavior

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Yuan, F., Zhang, D., Li, Z., Sun, H., Yu, Q., Wang, Q., Zhang, J., Wu, Y., Xi, K., & Wang, B. (2022). Unraveling the Intercorrelation Between Micro/Mesopores and K Migration Behavior in Hard Carbon. Small, 18(12), Article 2107113. https://doi.org/10.1002/smll.202107113