Confined Space Dual-Type Quantum Dots for High-Rate Electrochemical Energy Storage

Qingjun Yang, King Yan Chung, Xinlong Liu, Lin Sun, Jing Han, Yujue Yang, Tiandi Chen, Weidong Shi, Bingang Xu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

Abstract

Owing to the quantum size effect and high redox activity, quantum dots (QDs) play very essential roles toward electrochemical energy storage. However, it is very difficult to obtain different types and uniformly dispersed high-active QDs in a stable conductive microenvironment, because QDs prepared by traditional methods are mostly dissolved in solution or loaded on the surface of other semiconductors. Herein, dual-type semiconductor QDs (Co9S8 and CdS) are skillfully constructed within the interlayer of ultrathin-layered double hydroxides. In particular, the expandable interlayer provides a very suitable confined space for the growth and uniform dispersion of QDs, where Co9S8 originates from in situ transformation of cobalt atoms in laminate and CdS is generated from interlayer pre-embedding Cd2+. Meanwhile, XAFS and GGA+U calculations are employed to explore and prove the mechanism of QDs formation and energy storage characteristics as compared to surface loading QDs. Significantly, the hybrid supercapacitors achieve a high energy density of 329.2 µWh cm−2, capacitance retention of 99.1%, and coulomb efficiency of 96.9% after 22 000 cycles, which is superior to the reported QDs-based supercapacitors. These findings provide unique insights for designing and developing stable, ordered, and highly active QDs.

Original languageEnglish
JournalAdvanced Materials
DOIs
Publication statusAccepted/In press - 2024

Keywords

  • confined space
  • dual-type quantum dots
  • electrochemical energy storage
  • layered double hydroxides
  • stacked electrodes

ASJC Scopus subject areas

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering

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