Confined Lithium-Sulfur Reactions in Narrow-Diameter Carbon Nanotubes Reveal Enhanced Electrochemical Reactivity.
Chengyin FuMaría Belén OviedoYihan ZhuArthur von Wald CresceKang XuGuanghui LiMikhail E ItkisRobert C HaddonMiaofang ChiYu HanBryan M WongJuchen GuoPublished in: ACS nano (2018)
We demonstrate an unusual electrochemical reaction of sulfur with lithium upon encapsulation in narrow-diameter (subnanometer) single-walled carbon nanotubes (SWNTs). Our study provides mechanistic insight on the synergistic effects of sulfur confinement and Li+ ion solvation properties that culminate in a new mechanism of these sub-nanoscale-enabled reactions (which cannot be solely attributed to the lithiation-delithiation of conventional sulfur). Two types of SWNTs with distinct diameters, produced by electric arc (EA-SWNTs, average diameter 1.55 nm) or high-pressure carbon monoxide (HiPco-SWNTs, average diameter 1.0 nm), are investigated with two comparable electrolyte systems based on tetraethylene glycol dimethyl ether (TEGDME) and 1,4,7,10,13-pentaoxacyclopentadecane (15-crown-5). Electrochemical analyses indicate that a conventional solution-phase Li-S reaction occurs in EA-SWNTs, which can be attributed to the smaller solvated [Li(TEGDME)]+ and [Li(15-crown-5)]+ ions within the EA-SWNT diameter. In stark contrast, the Li-S confined in narrower diameter HiPco-SWNTs exhibits unusual electrochemical behavior that can be attributed to a solid-state reaction enabled by the smaller HiPco-SWNT diameter compared to the size of solvated Li+ ions. Our results of the electrochemical analyses are corroborated and supported with various spectroscopic analyses including operando Raman, X-ray photoelectron spectroscopy, and first-principles calculations from density functional theory. Taken together, our findings demonstrate that the controlled solid-state lithiation-delithiation of sulfur and an enhanced electrochemical reactivity can be achieved by sub-nanoscale encapsulation and one-dimensional confinement in narrow-diameter SWNTs.
Keyphrases
- solid state
- optic nerve
- ionic liquid
- gold nanoparticles
- density functional theory
- molecularly imprinted
- label free
- molecular dynamics
- ion batteries
- magnetic resonance
- carbon nanotubes
- electron transfer
- photodynamic therapy
- atomic force microscopy
- molecular dynamics simulations
- optical coherence tomography
- quantum dots
- molecular docking
- computed tomography
- water soluble
- mass spectrometry
- drug delivery
- aqueous solution
- single cell
- simultaneous determination
- tandem mass spectrometry