Composite Cathodes Based on Lithium-Iron Phosphate and N-Doped Carbon Materials

Batteries. 2022. Vol. 8. No. 12. Article 256.

Irina Stenina, Safikanov D., Minakova Polina, Novikova Svetlana A., Tatiana Kulova, Yaroslavtsev A. B.

The effect of different nitrogen-doped carbon additives (carbon coating from polyaniline,
N-doped carbon nanotubes, and N-doped carbon nanoparticles) on electrochemical performance
of nanocomposites based on the olivine-type LiFePO4 was investigated. Prepared materials were
characterized by XRD, SEM, TGA-MS, CHNS-analysis, IR-, Raman, and impedance spectroscopies.
Polyaniline deposition on the LiFePO4 precursor with following annealing lead to the formation of
a LiFePO4/C nanocomposite with a carbon coating doped with nitrogen. Due to nitrogen atoms
presence in carbon coating, the LiFePO4/N-doped carbon nanocomposites showed enhanced conductivity
and C-rate capability. The discharge capacities of the synthesized materials in LIBs were
close to the theoretical value at 0.1 C and retained high values with increasing current density. At
high C-rates, the best results were obtained for a more dispersed LiFePO4/C composite with carbon
coating prepared from polyaniline previously in situ deposited on LiFePO4 precursor particles. Its
discharge capacity reached 96, 84, 73, and 47 mAh g􀀀1 at 5, 10, 20, and 60 C-rates, respectively.

Keywords: cathode, CNTS, polyaniline, LiFePO4, Carbon coating, Nitrogen-doped carbon nanomaterials, lithium ion battery