A Stable Conversion and Alloying Anode for Potassium-Ion Batteries: A Combined Strategy of Encapsulation and Confinement

Shijian Wang, Pan Xiong (Corresponding author), Xin Guo, Jinqiang Zhang, Xiaochun Gao, Fan Zhang, Xiao Tang, Peter H.L. Notten, Guoxiu Wang (Corresponding author)

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Potassium-ion batteries based on conversion/alloying reactions have high potential applications in new-generation large-scale energy storage. However, their applications are hindered by inherent large-volume variations and sluggish kinetics of the conversion/alloying-type electrode materials during the repeated insertion and extraction of bulky K+ ions. Although some efforts have been focused on this issue, the reported potassium-ion batteries still suffer from poor cycling lifespans. Here, a superior stable antimony selenide (Sb2Se3) anode is reported for high-performance potassium-ion batteries through a combined strategy of conductive encapsulation and 2D confinement. The Sb2Se3 nanorods are uniformly coated with a conductive N-doped carbon layer and then confined between graphene nanosheets. The synergistic effects between conductive coating and confinement effectively buffer the large volumetric variation of the conversion/alloying anodes, which can maintain structural stability for superior cyclability. The as-prepared anodes exhibit a high reversible specific capacity of ≈590 mA h g−1 and outstanding cycling stability over 350 cycles. In situ and ex situ characterizations reveal a high structural integration of the large-volume-change Sb2Se3 anodes during a reversible K storage mechanism of two-step conversion and multistep alloying processes. This work can open up a new possibility for the design of stable conversion/alloying-based anodes for high-performance potassium-ion batteries.

Original languageEnglish
Article number2001588
Number of pages10
JournalAdvanced Functional Materials
Volume30
Issue number27
DOIs
Publication statusPublished - 1 Jul 2020

Keywords

  • 2D confinements
  • antimony selenides
  • conductive encapsulations
  • conversion/alloying anodes
  • potassium-ion batteries

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