Sulfur-doped lithium titanate/graphene oxide composite material, preparation method and application of sulfur-doped lithium titanate/graphene oxide composite material

Abstract

The invention relates to a sulfur-doped lithium titanate / graphene oxide composite material, a preparation method and application of the sulfur-doped lithium titanate / graphene oxide composite material.The preparation method comprises the following steps that: (a) a titanium source is dissolved in a solution, and stirring is performed, so that a titanium source solution is obtained; (b) a lithium source is dissolved in deionized water, stirring is performed, so that a lithium salt solution is obtained; (c) the lithium salt solution is added into the titanium source solution, stirring is performed, so that a mixed solution is obtained; (d) PVP and graphene oxide are added into the mixed solution, ultrasonic dispersion is carried out, then a hydrothermal reaction is carried out, centrifugingand drying are performed, so that a lithium titanate / graphene oxide precursor can be obtained; (e) the lithium titanate / graphene oxide precursor is sintered in a reducing atmosphere, so that a lithiumtitanate / graphene oxide composite material can be obtained; and (f) the lithium titanate / graphene oxide composite material is mixed with a sulfur source, an obtained mixture is sintered in a reducingatmosphere, so that the sulfur-doped lithium titanate / graphene oxide composite material can be obtained. A sodium ion battery applying the composite material prepared by the above preparation methodhas the advantages of high capacity and the like. The sulfur-doped lithium titanate / graphene oxide composite material can be used as the active material of the negative electrode of the sodium ion battery.

Description

technical field [0001] The invention belongs to the field of negative electrode materials, and relates to a graphene oxide composite material, in particular to a sulfur-doped lithium titanate / graphene oxide composite material, a preparation method and an application thereof. Background technique [0002] Due to the limited reserves of lithium in the earth's crust, it cannot be used in electric vehicles and large-scale energy storage at the same time. Therefore, it is necessary to develop other cheap energy storage systems as a substitute for lithium-ion batteries in the field of large-scale energy storage. . Sodium element is widely distributed in the earth's crust with a high abundance (2.75%), ranking sixth among all elements. At the same time, sodium and lithium belong to the same main group elements and have similar physical and chemical properties. Therefore, sodium-ion batteries have similar electrochemical reaction mechanisms and comparable electrochemical performanc...

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Problems solved by technology

However, lithium titanate also has some disadvantages, such as Ti in lithium titanate 4+ The lack of electrons on the 3d orbital makes its conductivity very low. At the same time, due to the large ionic radius of sodium ions, the ion diffusion coefficient of sodium ions in lithium titanate (10 -16 cm 2 the s -1 ) is much lower than the diffusion coefficient of lithium ions in lithium titanate (10 -9 ~10 -13 cm 2 the s -1 )

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