Reorganizing electronic structure of Li3V2(PO4)3 using polyanion (BO3)3− : towards better electrochemical performances
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Doping modification of electrode materials is a sought-after strategy to improve their electrochemical performance in the secondary batteries field. Herein, polyanion (BO3)3−-doped Li3V2(PO4)3 cathode materials were successfully synthesized via a wet coordination method. The effects of (BO3)3− doping content on crystal structure, morphology and electrochemical performance were explored by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). All the as-prepared samples have the same monoclinic structure; among them, Li3V2(PO4)2.75(BO3)0.15 sample has relatively uniform and optimized particle size. In addition, this sample has the highest discharge capacity and the best cycling stability, with an initial discharge capacity of 120.4 mAh·g−1, and after 30 cycles at a rate of 0.1C, the discharge capacity still remains 119.3 mAh·g−1. It is confirmed that moderate polyanion (BO3)3− doping can rearrange the electronic structure of the bulk Li3V2(PO4)3, lower the charge transfer resistance and further improve the electrochemical behaviors.
KeywordsLithium-ion batteries Cathode materials Li3V2(PO4)3 Polyanion doping (BO3)3−
This work was financially supported by the National Key Research and Development Program of China (No.2016YFB0100500) and the Beijing Co-construction Project (No. 20150939014).
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