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Keywords:

  • anodes;
  • electrochemistry;
  • lithium;
  • nanoparticles;
  • X-ray diffraction

Abstract

Li2CoTi3O8 powder has been synthesized by a simple citric nitrate method and was evaluated as an anode material for lithium-ion batteries. The X-ray diffraction (XRD) Rietveld refinement and X-ray photoelectron spectroscopy (XPS) measurements indicate the existence of Ti-site deficiency and a mixed-valence state of Co ions in the Li2CoTi3O8 structure. The refined site-occupation result gave a nonstoichiometric chemical formula of Li2CoTi2.682O8, which corresponds to a theoretical specific capacity of 322 mA h g−1, which is much higher than that of the stoichiometric material (233 mA h g−1). The synthesized Li2CoTi2.682O8 material exhibits high reversible capacity (ca. 320 mA h g−1), and excellent cycling stability and rate capability. A specific capacity of about 240 and 160 mA h g−1 can be achieved at 2 and 6 A g−1, respectively, by the Li2CoTi2.682O8 material. First-principles calculation demonstrates that Ti-site deficiency decreases the bandgap and thus facilitates the electron conduction.