Harbin Engineering University

About: Harbin Engineering University is a education organization based out in Harbin, Heilongjiang, China. It is known for research contribution in the topics: Control theory & Computer science. The organization has 31149 authors who have published 27940 publications receiving 276787 citations. The organization is also known as: HEU.

Effects of Ti and Mg Codoping on the Electrochemical Performance of Li3V2(PO4)3 Cathode Material for Lithium Ion Batteries

Abstract: Ti and Mg codoped Li3V2–2xTixMgx(PO4)3 (x = 0, 0.05, 0.10, 0.20, and 0.25) samples were prepared by a sol–gel method. The effects of Ti and Mg codoping on the physical and electrochemical characteristics of Li3V2(PO4)3 were investigated. Compared with the XRD pattern of the undoped sample, those of the Ti and Mg codoped samples have no extra reflections, which indicates that Ti and Mg enter the structure of Li3V2(PO4)3. According to the results of charge–discharge measurements, the initial capacity of Li3V2–2xTixMgx(PO4)3 at a low current density (0.2 C) decreases with increasing x. However, the discharge capacities at higher current densities (1 and 2 C) and the cycling stability are improved by a low amount of Ti and Mg codoping (x = 0.05), and moreover, EIS measurements indicate the lower charge transfer resistance of Li3V1.9Ti0.05Mg0.05(PO4)3. The improved electrochemical performance of Li3V1.9Ti0.05Mg0.05(PO4)3 can be attributed to its higher structural stability and smaller particle size. When x is ...

1D nanostructured Na7V4(P2O7)4(PO4) as high-potential and superior-performance cathode material for sodium-ion batteries.

Abstract: Tailoring materials into nanostructure offers unprecedented opportunities in the utilization of their functional properties. High-purity Na7V4(P2O7)4(PO4) with 1D nanostructure is prepared as a cathode material for rechargeable Na-ion batteries. An efficient synthetic approach is developed by carefully controlling the crystal growth in the molten sodium phosphate. Based on the XRD, XPS, TG, and morphological characterization, a molten-salt assisted mechanism for nanoarchitecture formation is revealed. The prepared Na7V4(P2O7)4(PO4) nanorod has rectangle sides and preferential [001] growth orientation. GITT evaluation indicates that the sodium de/intercalation of Na7V4(P2O7)4(PO4) nanorod involves V3+/V4+ redox reaction and Na5V3.5+4(P2O7)4(PO4) as intermediate phase, which results in two pairs of potential plateaus at the equilibrium potentials of 3.8713 V (V3+/V3.5+) and 3.8879 V (V3.5+/V4+), respectively. The unique nanoarchitecture of the phase-pure Na7V4(P2O7)4(PO4) facilitates its reversible sodium d...