title: Solvothermal synthesis of monodisperse LiFePO4 micro hollow spheres as high performance cathode material for lithium ion batteries.
abstract: A microspherical, hollow LiFePO4 (LFP) cathode material with polycrystal structure was simply synthesized by a solvothermal method using spherical Li3PO4 as the self-sacrificed template and FeCl2·4H2O as the Fe(2+) source. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the LFP micro hollow spheres have a quite uniform size of ~1 μm consisting of aggregated nanoparticles. The influences of solvent and Fe(2+) source on the phase and morphology of the final product were chiefly investigated, and a direct ion exchange reaction between spherical Li3PO4 templates and Fe(2+) ions was firstly proposed on the basis of the X-ray powder diffraction (XRD) transformation of the products. The LFP nanoparticles in the micro hollow spheres could finely coat a uniform carbon layer ~3.5 nm by a glucose solution impregnating-drying-sintering process. The electrochemical measurements show that the carbon coated LFP materials could exhibit high charge-discharge capacities of 158, 144, 125, 101, and even 72 mAh g(-1) at 0.1, 1, 5, 20, and 50 C, respectively. It could also maintain 80% of the initial discharge capacity after cycling for 2000 times at 20 C.
authors: Department of Physics and Materials Science, City University of Hong Kong , 83 Tat Chee Avenue, Kowloon Tong, Hong Kong, P. R. China.
authors: Shiliu
authors: S
authors: Yang
authors: Mingjun
authors: M
authors: Hu
authors: Liujiang
authors: L
authors: Xi
authors: Ruguang
authors: R
authors: Ma
authors: Yucheng
authors: Y
authors: Dong
authors: C Y
authors: CY
authors: Chung
mesh_terms: D002244:Carbon / Q000737:chemistry; D011211:Electric Power Supplies; D004566:Electrodes; D005296:Ferrous Compounds / Q000737:chemistry; D007474:Ion Exchange; D007477:Ions / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D010316:Particle Size; D010710:Phosphates / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*
chemical_list: D005296:Ferrous Compounds; D007477:Ions; C473349:LiFePO4; D010710:Phosphates; D012997:Solvents; D002244:Carbon; D008094:Lithium; D007501:Iron; C029451:ferrous chloride