High-performance lithium iron phosphate with phosphorus-doped carbon layers for lithium ion batteries

Abstract

A novel composite of LiFePO 4 with phosphorus-doped carbon layers has been prepared via a simple hydrothermal method using glucose as the carbon source to generate the carbon coating and triphenylphosphine as the phosphorus source. Effects of phosphorus doping on the phase purity, morphology and electrochemical performance of the materials are studied by the characterizations of Xray diffraction, Raman spectra, scanning electron microscopy, high resolution transmission electron 10 microscopy and electrochemical techniques. It is indicated that phosphorus doping into the carbon layers is beneficial for the graphitization of the carbon. Phosphorus in the carbon layers exists in the form of P-C bond and its concentration depends on the second calcination temperature. Moreover, phosphorus-doped carbon layers on the particle surface make the charge transfer resistance decreased remarkably from 156.5 Ω to 49.1 Ω, which can be ascribed to the free carriers donated by phosphorus. The as-prepared LiFePO 4 15 with phosphorus-doped carbon layers calcined at 600 o C shows the best electrochemical performance with a discharge capacity of 124.0 mAh g -1 at the high rate of 20 C and an excellent retention rate of 91.4% after 50 cycles. The LiFePO 4 with phosphorus-doped carbon layers exhibits excellent electrochemical performances especially at high current rates, which is a promising cathode material for high-performance lithium ion batteries.

Phosphorus-doped porous carbon derived from rice husk as anode for lithium ion batteries

“…As expected, two peaks at 132.9 eV and 130.4 eV appeared after phosphorus doping which could be associated to characteristic peaks of P-O and P-C bonding, respectively35,36 . It exhibits typical amorphous carbon structure with peaks at around 25° and 43° corresponding to the (002) and (100) planes of graphite.…”

Boron and Nitrogen Codoped Carbon Layers of LiFePO4 Improve the High-Rate Electrochemical Performance for Lithium Ion Batteries

“…These were then successfully applied to the existing commercial LiFePO 4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 type co-doped carbon coating on the material can generate the synergistic effect to elevate the high-rate capacity much higher than the sum of single doping. This is attributed to the electron-type and the hole-type carrier donated by nitrogen and boron atoms.…”

“…Conductive surface modifications towards carbon coating of olivine-structured lithium iron phosphate (LiFePO 4 ) have attracted significant attention due to its high-efficiency and environmental benign in the development of lithium ion battery cathode materials [1][2][3][4][5] .…”

Mass production of LiFePO4/C energy materials using Fe–P waste slag

“…LiFePO 4 nanoparticles prepared by a facile solvothermal process with water/N-methyl-2-pyrrolidone (NMP) solvent system exhibit excellent electrochemical performance [11]. In addition, LiFePO 4 /NiP nanospheres prepared using a spraying technique has a high electronic conductivity [12]. It was also reported that surface modifications by carbon coating and atomic-level doping with alien ions are effective to improve the electronic conductivity [13].…”