Synthesis and electrochemical properties of mixed-phase α /β -LiVOPO4/C composites

Abstract

Abstract Mixed-phase αx/β1-x-LiVOPO4/C (x\xa0=\xa00.1, 0.3, 0.5, 0.7, 0.9) composites were synthesized by the solid-phase sintering method. X-ray diffraction (XRD) analyses revealed that a series of composites were comprised of pure triclinic α-LiVOPO4 and orthorhombic β-LiVOPO4 components. The mixed-phase materials exhibit better rate performance than whether pure triclinic α-LiVOPO4/C or orthorhombic β-LiVOPO4/C. The α0.5/β0.5-LiVOPO4/C (α:β\xa0=\xa01:1) composite exhibit superior high-rate capability. When cycled at 2C and 5C, the initial discharge capacities of the α0.5/β0.5-LiVOPO4/C composite are 81.1\xa0mAh g−1 and 69.8\xa0mAh g−1 respectively, which are significantly higher than those of the pure α-LiVOPO4/C (30.6\xa0mAh g−1 and 18.6\xa0mAh g−1, respectively) and β-LiVOPO4/C (56.8\xa0mAh g−1 and 36.9\xa0mAh g−1, respectively). The improved electrochemical performance could be attributed to the mixed phase possess an open framework and stable structure.