Electrochemical Properties of Li1.1V0.75W0.075Mo0.075O2/Graphite Composite Anodes for Lithium-ion Batteries

Novel type Li1.1V0.9-2xWxMoxO2 powders were prepared by a solid-state reaction of Li2CO3, V2O3, WO2 and MoO2 precursors in a nitrogen atmosphere containing 10 mol % hydrogen gas, and assessed as anode materials in lithium-ion batteries. The specific charge and discharge capacities of the Li1.1V0.9-2xWxMoxO2 anodes were higher than those of the bare Li1.1V0.9O2 anode. The cyclic efficiency of these anodes was approximately 73.3% at the first cycle, regardless of the presence of W and Mo doping. The composite anode, which was composed of Li1.1V0.75W0.075Mo0.075O2 (20 wt %) and natural graphite (80 wt %), demonstrated reasonable specific capacity, high cyclic efficiency, and good cycling performance, even at high rates without capacity fading. based on this material could be enhanced significantly because of its low working potential of < 0.3 V vs. Li/Li + during the charge and discharge reactions. The potential of this material as a high-density anode electrode has prompted intensive research on its structure and valence state. Li1.1V0.9O2 has an ordered layered crystalline structure with Li + and V +3 ions occupying alternate (111) planes, and exhibits a hexagonal structure. 8,9 After lithium intercalation, Li1.1V0.9O2 is converted to Li2.1V0.9O2, corresponding to the P-3m1 space group, and the oxidation state of vanadium ions is reduced from V(III) to V(II). The layered structure of Li1.1V0.9O2, gives it a relatively low volume change of 25% during the cycling process compared to that of highly capacitive silicon or tin-based anode materials. On the other hand, the electrochemical properties of Li1.1V0.9O2 might be insufficient for high-current applications owing to its low conductivity. Therefore, surface modification or other treat- ment methods should be applied to enhance the rate cap- ability. Metal doping is one of the most effective methods for improving the electrochemical properties of Li1.1V0.9O2. W and Mo-based oxide materials are used as dopants for Li1.1V0.9O2, which is used as an anode material in lithium-ion batteries. 10,11 These metals are suitable for the preparation of high-density anodes because of their high intrinsic density, low cost and non-toxic environment. In this study, a simple solid-state reaction was used to prepare a conducting Li1.1V0.9-2xWxMoxO2 anode material using a metal doping process. The electrochemical proper- ties of the anodes of these lithium-ion batteries were ex- amined using a range of analytical techniques. Experimental