Electrochemical Li Insertion in B-Doped Multiwall Carbon Nanotubes

Abstract

Electrochemical Li insertion into boron-doped multiwall carbon nanotubes (B-MWNTs) was investigated in a nonaqueous medium. Transmission electron microscopy observations showed that the walls of the tubes consisted of highly aligned ca. 35-45 graphene layers with good 3D ordering feature. Raman studies revealed that boron doping in multiwall carbon nanotubes (MWNTs) destroyed the local hexagonal symmetry. X-ray photoelectron spectra of B-MWNTs further supported the results of Raman spectra and confirmed the presence of BC3 nanodomains. N2 adsorption measurements indicated that the Brunauer-Emmett-Teller (BET) surface areas of undoped and doped nanotubes were 10 and 12 cm2/g, respectively, with almost similar mesopore volumes. Galvanostatic discharge-charge measurements revealed that the reversible capacity was 156 mAh/g for undoped and 180 mAh/g for B-doped nanotubes in the first cycle with almost equal coulomb efficiencies of 55-58%. The coulomb efficiency increased to more than 90% after the second cycle. Cyclic voltammetry (CV) showed that highly reversible intercalation/deintercalation of Li occurred with some undesirable reduction processes in the initial discharge process. The cycle lives of both undoped and doped samples were quite satisfactory. Slow-scan CV confirmed that the intercalation of lithium in these nanotubes occurred through staging transition, usually observed in Li graphite intercalation compounds. © 2001 The Electrochemical Society. All rights reserved.

First-principles study on the enhancement of lithium storage capacity in boron doped graphene

“…The maximum capacity of CNTs can be increased to as high as 1000 mAh/g ͑in the form of Li 2.7 C 6 ͒ by chemical etching 4 or ball-milling, 5 which open up paths allowing Li ions to diffuse inside the CNTs. Ever since boron doped CNTs with different B versus C ratios have been synthesized, [6][7][8] they have been expected to have higher Liion storage capability than pristine CNTs, and this has been confirmed both experimentally 9 and theoretically. 10 Additionally, boron doped carbonaceous materials have exhibited higher reversible capacity and better cycling stability than their pure counterparts.…”

A first-principles study of lithium absorption in boron- or nitrogen-doped single-walled carbon nanotubes

“…Until now, Li absorption in B-or N-doped SWCNT has not been investigated widely. Mukhopadhyay et al [32] investigated the electrochemical Li insertion in B-doped MWCNT. They found that the B-doped MWCNTs increased the Li insertion capacities due to their higher specific surface area, better 3D ordering, larger defect concentration and higher conductivity.…”

Recent progress of computational investigation on anode materials in Li ion batteries

“…Hence, boron-carbon composite nanotubes are promising anode materials to offer higher diffusion rate and greater Li storage capacity. Experimentally, Mukhopadhyay et al [24] found that, though the Bdoping effects were not dramatic, B-doped multi-walled CNTs showed greater Li storage capacity because of higher specific surface area, larger defect concentration, and higher conductivity.…”