Research On Transition Metal Oxide Electrode Materials

Currently, researchers focus more on the electrode materials of transition metal oxides, because they have lots of advantages such as large capacity, low cost, adapting business development and so on.However, after more study about them, there are a few problems found by people. These problems are mainly electrode pulverization and relatively larger resistivity. Electrode pulverization is caused by the increased volume of electrode during charge-discharge process and leads to the worse contact with the current collector and decreasing the capacity of lithium ion battery. Larger resistivity would reduce the rate capability, as a result, it restricts the fast charge-discharge ability. Generally, researchers take the approaches of nanocrystallization, doping and surface modification to solve the above problems.In the context, we discuss about the two synthesized electrode materials which are transition metal oxides, and analyze their structure and electrochemical performance. Firstly, using the technique of electrospinning, we have fabricated successfully the one-dimensional nanomaterials of MoO2. Because the MoO2 of nanostructures has a relatively higher activity, it can store lithium in two ways of the embedded lithium storage and the conversion of lithium storage, it shows a stronger capacity of lithium storage. With the operations of low temperature stability and high temperature reduction, the Mo O2 is coated successfully by the carbon from the PVA and is formed a core-shell structure. As a result, the volume expansion of electrode material is reduced and the synthesized electrode material has the better cycling stability and rate capability.Then, LiFexNi1/3-xCo1/3Mn1/3O2(0.000 ? x ? 0.267) microspheres have been synthesized by the approach using manganese carbonate microspheres as self-template and substituting stoichiometric iron for nickel. XRD analysis shows that the obtained materials have the layered ?-NaFeO2 structure. With the addition of iron, lattice parameters and specific capacities of these samples increase in the low-x region(x? 0.133) and reach their maximum values at x = 0.133, which means moderate substitution of iron can enhance the electrochemical performance. Comparing with the others, when x is equal to 0.133, the sample exhibits a relatively superior electrochemical performance.