Study of pristine and carbon-coated LiCoPO4 olivine material synthesized by modified sol–gel method

Abstract

LiCoPO 4 and LiCoPO 4 /C electrode active material was synthesized by a simple single-step protocol namely citric acid-assisted, isopropanol-added sol-gel method. Structural and morphology studies reveal the formation of single-phase products of pristine as well as in situ carbon-coated nano-sized grains of genuine purplecolored product of LiCoPO 4 and black-colored LiCoPO 4 /C due to uniform carbon coatings, respectively. In situ carbon coating was confirmed by scanning transmission electron microscopy imaging which exhibits the in situ nanocarbon coating networks. The electrode active characteristics of the synthesized products confirmed by resolved cyclic voltammograms corresponding to cobalt redox couple (Co 2+ /Co 3+ ) confirm the lithium extraction/insertion reversible processes. Carbon coating ensures better resolved near symmetric redox peaks with increased current profile indicative of enhanced rate capability (Li + extraction/insertion), presumably due to the enhanced electrode conductivity of the host matrix by means of carbon coating.

Influence of gradual cobalt substitution on lithium nickel phosphate nano-scale composites for high voltage applications

“…The reason for that may be either presence of carbon derived Table 1 The comparison of our study to the published studies of some of the LiNiPO 4 or Li(Ni-Co)PO 4 -C articles (the background color in red indicates similarities and green color indicates non-similarities with our work). 6 11 References mentioned in the table: [11,12,[16][17][18][19][20][21][22][23][24][25][26][27][28][29]. materials or reductive thermodynamic conditions keeping Ni 2+ from oxidation to Ni 3+ , which ensures the formation of impurity free samples.…”

Polyol Mediated Synthesis and Microstructural Features of Polycrystalline LiMPO4 (M = Mn and Co) Olivine Phosphates for Lithium Batteries

“…4 shows the FTIR spectra of LiMPO4 (M = Mn and Co) phospho-olivine material which confirms the chemical structure of the functional material. The structural edifice of olivine phase material arranged in the order of LiO6 and MO6 octahedra bonded with strong PO4 3polyanion 14,16,17 . Generally, the internal vibrations of LiMPO4 were conquered by the fundamental modes ν1-ν4 of polyanion.…”

Nonisothermal Kinetics Study with Isoconversional Procedure and DAEM: LiCoPO4 Synthesized from Thermal Decomposition of the Precursor

“…The successful development and commercialization of LiFePO 4 as a cathode for lithium-ion batteries has provoked strong interest on other transition metal phosphates such as LiMnPO 4 and LiCoPO 4 . − Owing to high operating potential close to 4.8 V vs Li/Li + and relatively high theoretical specific capacity (167 mA h g –1 ), LiCoPO 4 is regarded as a promising 5 V electrode material for high power batteries. So, recently, various methods have been developed to synthesize LiCoPO 4 compounds, including solid-state reaction, − hydrothermal synthesis (or Solvothermal synthesis), − sol–gel method, − coprecipitation, optical floating zone method, radio frequency magnetron sputtering, electrostatic spray deposition technique, spray pyrolysis method, , rheological phase method, and microwave heating method . Different raw materials and synthesis methods will result in different electrochemical properties of LiCoPO 4 associated with the crystallization temperature, crystallite size, and morphology.…”