Synergistic design of g-C3N4-supported CNTs: experimental and DFT insights for enhanced electrochemical performance in flexible Li-S batteries

Vijay K. Tomer*, Rameshwar L. Kumawat, Otavio Augusto Titton Dias, Ritu Malik*, George C. Schatz, Mohini Sain

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

In addressing the shuttle effect and sluggish redox kinetics of lithium polysulfides (LiPSs) in lithium-sulfur batteries, we developed a novel heterostructure combining 1D carbon nanotubes (CNTs) grown on a 2D sheet of graphitic carbon nitride (g-C3N4) to improve conversion reaction kinetics and LiPS adsorption capacity. The high pyridine N content in g-C3N4 facilitates homogeneous Li ion deposition and enhances affinity between Li and N atoms. Extensive experimental characterization and density functional theory (DFT) calculations validated the interaction between g-C3N4-CNT/S and LiPSs. In pouch cell evaluation, the hybrid g-C3N4-CNT/S cathode, with ∼70% sulfur loading, demonstrated outstanding rate performance, delivering ∼895 mA h g−1 at 0.1C and retaining ∼500 mA h g−1 even at 1.5C under lean electrolyte conditions (E/S ∼5 μl mg−1). Long-term stability over 250 cycles, with a capacity retention of 86% and a coulombic efficiency (CE) of 90.4%, was achieved, even with an elevated sulfur loading of 6.2 mg cm−2. Post-mortem investigation using X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) elucidated surface chemistry changes and elemental composition alterations, highlighting the formation of various reaction products during charge-discharge cycles. This study underscores the cost-effective heterostructure strategy's potential for advancing LiSBs in practical applications.

Original languageEnglish (US)
Pages (from-to)15814-15828
Number of pages15
JournalJournal of Materials Chemistry A
Volume12
Issue number26
DOIs
StatePublished - May 16 2024

ASJC Scopus subject areas

  • General Chemistry
  • Renewable Energy, Sustainability and the Environment
  • General Materials Science

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