Hollow silica spheres encapsulated with nitrogen-doped carbon frame as an anode for high performance Li-ion capacitor: Correlating experimental and theoretical studies

A.C. Lokhande, K. Badawy, D. Malvekar, J.H. Kim, N. Singh, S. Mao, D. Choi

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The sluggish reaction kinetics of the silica (SiO2) electrode due to low electrical conductivity and high-capacity degradation due to volume expansion result in poor electrochemical performance. To overcome these drawbacks, we have fabricated hollow SiO2 microspheres (HSiO2) encapsulated in an N-doped carbon frame (C[sbnd]N) using a simple template-based method followed by the carbonization treatment. The significance of such a unique structural architecture is that the HSiO2 microspheres provide additional space for volume expansion which restores the structural integrity of the hollow SiO2 microspheres through buffering effect. At the same time, the C[sbnd]N enhances electrical conductivity, which accelerates Li+ diffusion and promotes high charge accommodation. As a result, the collective contribution of HSiO2 and C[sbnd]N results in superior electrochemical performance in terms of improved capacity, accelerated reaction kinetics (rate capability), and higher cyclic stability. The density functional theory (DFT) validates the enhanced interactive characteristics of the HSiO2/C[sbnd]N composite electrode with Li ions, which include improved charge transfer kinetics, high binding energy, and low migration barrier. The HSiO2/C[sbnd]N composite electrode employed in the lithium-ion capacitor (LIC) demonstrates exceptional performance, with a remarkable energy density of 161.76 Wh/kg, a high power density of 23.52 kW/kg, and an outstanding stability of 87 % for 20,000 cycles, outperforming most of the previously reported anodes based on sulfides and oxides. © 2023 Elsevier Ltd
Original languageBritish English
JournalJournal of Energy Storage
Volume72
DOIs
StatePublished - 2023

Keywords

  • Anodes
  • Binding energy
  • Carbon
  • Carbonization
  • Charge transfer
  • Density functional theory
  • Doping (additives)
  • Electric conductivity
  • Electrochemical electrodes
  • Ions
  • Kinetics
  • Lithium
  • Lithium compounds
  • Lithium-ion batteries
  • Microspheres
  • Nitrogen
  • Reaction kinetics
  • Silicon
  • Sulfur compounds
  • Composites electrodes
  • Electrical conductivity
  • Electrochemical performance
  • Hollow silica spheres
  • Lithium-ion capacitors
  • Nitrogen-doped carbons
  • Nitrogen-doping
  • Performance
  • SiO 2
  • Volume expansion
  • Silica

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