Preparation and application of two-dimensional-structure tungsten trioxide coated graphene negative electrode material

Abstract

The invention discloses a preparation method and application of a graphene-coated tungsten trioxide negative electrode material with a two-dimensional sheet structure. The chemical general formula of the composite material is WO3@rGO. The preparation method comprises the following steps: (1) preparing a graphene dispersion liquid; (2) regulating and controlling the pH value of a mixed solution of a sodium tungstate metal source liquid and the graphene dispersion liquid; (3) synthesizing a WO3@rGO composite material precursor in one step by a hydrothermal synthesis method; and (4) carrying out heat treatment on the powder material in a nitrogen atmosphere to obtain a final product WO3@rGO. The three problems of poor cycling stability, low reversible cycling specific capacity and unstable structure of the material in the charging and discharging process of the transition metal oxide trioxide negative electrode material can be effectively solved. The result shows that the lithium ion deintercalation / intercalation capacity and the cycling stability of the tungsten trioxide single electrode serving as the negative electrode of a lithium ion battery are effectively improved by compounding the tungsten trioxide with the two-dimensional sheet structure and the graphene.

Description

technical field [0001] The invention belongs to the field of high-energy-density lithium-ion battery materials, and relates to a preparation method and application of a two-dimensional nanosheet structure tungsten oxide-coated graphene negative electrode material synthesized by a one-step hydrothermal method. Background technique [0002] In recent studies on high-capacity anodes for lithium-ion batteries, common transition metal oxides including ferric oxide, manganese dioxide, vanadium pentoxide, tungsten trioxide, and cobalt tetroxide with high theoretical capacities have been extensively studied. Among them, tungsten trioxide has received extensive attention due to its special structure and characteristics: first, it has stable thermodynamic properties at room temperature, and the monoclinic distorted ReO 3 type structure contains monovalent cations (Li + and Na + ) lattice channel. Furthermore, its non-toxic properties, low cost and 700mA h g -1 The advantage of lar...

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Problems solved by technology

However, tungsten trioxide also suffers from serious disadvantages: i) poor cyclability due to massive volume expansion and pulverization during charge / discharge; ii) low conductivity and strong polarization at higher current densities performance, greatly reducing battery performance and limiting power density

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