Nanocomposite LiFePO4·Li3V2(PO4)3/C synthesized by freeze-drying assisted sol-gel method and its magnetic and electrochemical properties
RIS ID
119063
Abstract
Nano-sized LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C was synthesized via a sol-gel route combining with freeze-drying. X-ray diffraction results show that this composite mainly consists of olivine LiFePO 4 and monoclinic Li 3 V 2 (PO 4 ) 3 phases with small amounts of V-doped LiFePO 4 and Fe-doped Li 3 V 2 (PO 4 ) 3 . The magnetic properties of LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C are significantly different from LiFePO 4 /C. Trace quantities of ferromagnetic impurities and Fe 2 P are verified in LiFePO 4 /C and LiFePO 4 ·Li 3 V 2 (PO 4 ) 3 /C by magnetic tests, respectively. LiFe-PO 4 ·Li 3 V 2 (PO 4 ) 3 /C possesses relatively better rate capacities and cyclic stabilities, especially at high charge-discharge rates. The initial discharge capacities are 136.4 and 130.0 mA h g −1 , and the capacity retentions are more than 98% after 100 cycles at 2 C and 5 C, respectively, remarkably better than those of LiFePO 4 /C. The excellent electrochemical performances are ascribed to the mutual doping of V 3+ and Fe 2+ , complementary advantages of LiFePO 4 and Li 3 V 2 (PO 4 ) 3 phases, the residual high-ordered carbon and Fe 2 P with outstanding electric conductivity in the nanocomposite.
Publication Details
Liu, L., Xiao, W., Guo, J., Cui, Y., Ke, X., Cai, W., Liu, J., Chen, Y., Shi, Z. & Chou, S. (2018). Nanocomposite LiFePO4·Li3V2(PO4)3/C synthesized by freeze-drying assisted sol-gel method and its magnetic and electrochemical properties. Science China Materials, 61 (1), 39-47.