Opening Mechanism of Closed Graphitized Tips via Low-Temperature Surface Fluorination

Abstract

When treated at high temperatures, petroleum coke materials exhibit structures which are formed of graphitized closed tips. The external surface of these materials is mostly formed of hemispherical tips similar to those found in carbon nanotubes. By low-temperature fluorination using CF 4 radio-frequency plasmas, an opening mechanism of the closed tips occurs, thus allowing a drastic increase of possible intercalation into the structure. The interest for Li + storage in Li-ion batteries has been demonstrated by capacity measurements which show an enhancement of the Li + capacity retention into the host materials.

Surface Modification of Carbon Anodes for Lithium Ion Batteries by Fluorine and Chlorine

“…They are carbon coating [1][2][3][4][5][6][7][8][9][10][11][12][13][14], metal or metal oxide coating [15][16][17][18][19][20][21][22][23][24][25], surface oxidation [26][27][28][29][30][31][32][33], surface fluorination and chlorination [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52], and polymer, Si or Sb coating …”

Distinct Infrared Spectral Signatures of the 1,2- and 1,4-Fluorinated Single-Walled Carbon Nanotubes: A Molecular Dynamics Study

“…The discovery of carbon nanotubes (CNTs) has led to an explosion of studies focusing on understanding and controlling CNT atomic and electronic properties, as motivated by a variety of electronics, − biological, − materials, − energy, − and other applications. Chemical functionalization of CNT sidewalls provides one of the most efficient routes to the desired property control.…”

“…Fluoride atoms and other substituents on the CNT surface can be used to transform CNT films between the superhydrophobic and nearly hydrophilic states. , Control of surface adsorption properties by covalent and noncovalent CNT functionalization leads to superior CNT−polymer composites, materials with improved friction properties, and strongly interconnected CNT blocks . Fluorination and defluorination reactions form the basis for CNT applications in hydrogen storage and Li ion batteries . Finally, complexation of CNTs with organic sensitizers leads to promising photovoltaic materials …”

“…24 Fluorination and defluorination reactions form the basis for CNT applications in hydrogen storage 26 and Li ion batteries. 25 Finally, complexation of CNTs with organic sensitizers leads to promising photovoltaic materials. 27 Generally, CNTs are chemically nonreactive and are hard to functionalize due to the efficient carbon-carbon bonding.…”