Mesoporous carbon-coated LiFePO4nanocrystals co-modified with graphene and Mg2+doping as superior cathode materials for lithium ion batteries

• DOI: 10.1039/c3nr04611g
• Publication Date: 2013-11-04T10:01:31Z
• Authors: Bo Wang; Binghui Xu; Tiefeng Liu; Peng Liu; Chenfeng Guo; Shuo Wang; Qiuming Wang; Zhigang Xiong; Dianlong Wang; X. S. Zhao
• Keywords: Rietveld Refinement; Carbon fibers

In this work, mesoporous carbon-coated LiFePO4 nanocrystals further co-modified with graphene and Mg2+ doping (G/LFMP) were synthesized by a modified rheological phase method to improve the speed of lithium storage as well cycling stability. The structure was designed realized introducing bead milling technique, which assisted in forming sucrose–pyrolytic carbon nanoparticles template for generating mesopores. For comparison purposes, samples only (G/LFP) or (LFMP) pure (LFP) also prepared investigated. Microscopic observation nitrogen sorption analysis have revealed morphologies as-prepared composites. X-ray diffraction (XRD) Rietveld refinement data demonstrated that Mg-doped is single olivine-type crystallized shortened Fe–O P–O bonds lengthened Li–O bond, resulting an enhanced Li+ diffusion velocity. Electrochemical properties been investigated after assembling coin cells composites cathode active materials. Remarkably, G/LFMP composite has exhibited best electrochemical properties, including fast performance excellent cycle That because modification provided sites nuclei, restricted situ crystallite growth, increased electronic conductivity reduced interface reaction current density, while, improved intrinsically ionic transfer LFP crystals. Moreover, composite, component plays role "cushion" it could quickly realize capacity response, buffering impact LFMP under conditions high-rate charging discharging, results pre-eminent rate capability