University of California-Riverside presented its research on its use of water-triethylene glycol (TEG) as a solvent to synthesize LiFePO4 (LFP) nanorods with uniform size during a meeting of the American Chemical Society as part of the 245th National Meeting & Exposition of the American Chemical Society. The following is the abstract of that presentation.
Solvothermal synthesis, growth mechanism, and performance of LiFePO4 nanorods used as a cathode material in lithium ion batteries
David Kisailus, University of California-Riverside
Phone: 951-827-2260
Email: david@engr.ucr.edu
We report the use of water-triethylene glycol (TEG) as a solvent to synthesize LiFePO4 (LFP) nanorods with uniform size. TEG, a reducing agent in the reaction, promotes the formation of LiFePO4. Crystal phase and growth behavior were monitored by powder X-ray diffraction (XRD), synchrotron X-ray Diffraction, as well as transmission electron microscopy (TEM), while particles morphologies were investigated with scanning electron microscope (SEM). Three crystal growth mechanisms during the synthesis were interpreted based on the time study of the samples. Initially, the nucleation of LFP (20nm thick sheets) occurred accompanying with the formation of Fe3(PO4)2•8H2O (vivianite). This metastable phase evolved into spindle-like olivine LiFePO4 through oriented attachment (OA) of LFP primary nanosheets. With the increasing reaction time, the pH decreased with the concurrent formation of LiFePO4. The dissolution-recrystallization process, i.e. Ostwald ripening (OR), results in evenly distributed
LiFePO4 nanorods due to the increased solubility of LiFePO4. The mechanism (from nanosheet to spindle to rod) revealed by this study will help develop guidelines to control the size and morphological features of LFP more precisely.
Solvothermal synthesis, growth mechanism, and performance of LiFePO4 nanorods used as a cathode material in lithium ion batteries
David Kisailus, University of California-Riverside
Phone: 951-827-2260
Email: david@engr.ucr.edu
We report the use of water-triethylene glycol (TEG) as a solvent to synthesize LiFePO4 (LFP) nanorods with uniform size. TEG, a reducing agent in the reaction, promotes the formation of LiFePO4. Crystal phase and growth behavior were monitored by powder X-ray diffraction (XRD), synchrotron X-ray Diffraction, as well as transmission electron microscopy (TEM), while particles morphologies were investigated with scanning electron microscope (SEM). Three crystal growth mechanisms during the synthesis were interpreted based on the time study of the samples. Initially, the nucleation of LFP (20nm thick sheets) occurred accompanying with the formation of Fe3(PO4)2•8H2O (vivianite). This metastable phase evolved into spindle-like olivine LiFePO4 through oriented attachment (OA) of LFP primary nanosheets. With the increasing reaction time, the pH decreased with the concurrent formation of LiFePO4. The dissolution-recrystallization process, i.e. Ostwald ripening (OR), results in evenly distributed
LiFePO4 nanorods due to the increased solubility of LiFePO4. The mechanism (from nanosheet to spindle to rod) revealed by this study will help develop guidelines to control the size and morphological features of LFP more precisely.
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