Carbon coating on the current collector and LiFePO4 nanoparticles – Influence of sp and sp-like disordered carbon on the electrochemical properties

The use of Raman and XPS spectroscopy to study the cathode material of LiFePO4/C

“…Higher ratios sp 2 /sp 3 correlate with the more graphite-like nature of the carbon coating and hence with higher electronic conductivity. [7][8][9][10][11] In our work, a fraction of sp 2 /sp 3 carbon is estimated using only one excitation line at 523 nm and can be used, as was shown in 7 , as a semiquantitative estimate. The Raman spectra (Fig.…”

“…We analyzed four peaks at ~1200, 1340, 1520 and 1600 cm -1 , which are analogous to the curves presented in literature. [7][8][9][10][11] Two broad bands of them at ~1340 and ~1600 cm -1 correspond to D (disorder/defect band) and G (graphitic band) carbon particles respectively. The range ~1600 cm -1 is associated with graphite stretching mode E2g.…”

“…It is related to different disorder types in the graphite structure (in the graphene layer): graphite domains of finite size, grain faces, substitution of C atoms by N or other additions, sp 3 O n L i n e F i r s t hybridized carbon, etc. [7][8][9] Two additional bands, which are necessary for satisfactory analysis, are located at ~ 1200 cm -1 and 1520 cm -1 related to sp 3 -type carbon, which is often observed in amorphous carbon compounds. To assess the nature of the carbon coating using decomposed spectra, the peak intensity ratio of bonds D and G (ID/IG = I1340/I1600) is used.…”

Cellulose‐Templated, Dual‐Carbonized Na3V2(PO4)3 for Energy Storage with High Rate Capability

“…As shown in Figure A , the two intense peaks at 1350 (D) and 1590 cm −1 (G) originated from sp 2 ‐carbon species, and the other two peaks at 1180 and 1490 cm −1 were assigned to sp 3 ‐type carbon. The relative contents of sp 2 and sp 3 carbon were estimated from the integrated area ratio of sp 2 and sp 3 peaks ( A sp2 / A sp3 ) according to the literature . We found that the content ratio of the sp 2 and sp 3 carbon of CS‐NVP, C‐NVP, and S‐NVP were 4.34, 3.64, and 3.53, respectively.…”

“…The relative contents of sp 2 and sp 3 carbon were estimated from the integrated area ratio of sp 2 and sp 3 peaks (A sp2 /A sp3 ) according to the literature. [34][35] We found that the content ratio of the sp 2 and sp 3 carbon of CS-NVP, C-NVP, and S-NVP were 4.34, 3.64, and 3.53, respectively. According to X-ray photoelectron spectroscopic analysis, the C 1s XPS spectra of carbonized NVPs exhibited multiple peaks at 284.7, 285.8, 287.2, and 289.1 eV, which correspond to sp 2 carbon, sp 3 carbon, CÀO bonding, and C=O bonding ( Figure S3).…”