Monoatomic dispersed in-situ growth nitrogen atom-doped carbon nanosphere graphene foam, preparation method and application

Abstract

The invention relates to the technical field of new energy materials, in particular to a monoatomic dispersed in-situ growth nitrogen atom-doped carbon nanosphere graphene foam, a preparation method and application, wherein carbon nanospheres grow in situ on graphene foam, and the carbon nanospheres are doped with nitrogen atoms and metal single atoms. The preparation method comprises the following steps: preparing graphene foam on the surface of a foam metal template by adopting a vapor deposition method, then growing nitrogen-containing organic nanospheres on the surface of the graphene foam in situ, calcining, and removing the foam template in sequence to obtain the graphene foam doped with nitrogen atoms and metal monatomic carbon nanospheres through in-situ growth. When the obtained composite material is applied to the lithium-sulfur battery, the utilization rate of active substances can be greatly improved, and the overall electrochemical performance is excellent.

Description

technical field [0001] The invention relates to the technical field of new energy materials, in particular to a monoatomically dispersed graphene foam, a preparation method and an application of carbon nanospheres doped with nitrogen atoms grown in situ. Background technique [0002] With the rapid development of society, higher requirements are put forward for the performance of electric energy storage systems, especially for the energy density of secondary battery systems. Although traditional lithium-ion batteries have the advantages of high specific energy, high working voltage, long cycle life, and no environmental pollution, the theoretical specific capacity of commercial lithium-ion battery cathode materials generally does not exceed 300Wh kg -1 , cannot effectively meet the higher energy density requirements. Therefore, the development of a new generation of secondary battery system with high theoretical specific capacity has become the focus of current research. I...

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Problems solved by technology

Therefore, when elemental sulfur is used alone as the positive electrode of the lithium-sulfur battery, it will lead to difficulties in electron transport, a decrease in the electrochemical reaction rate, and a decrease in the utilization rate of the active material sulfur, thereby affecting the electrochemical performance of the lithium-sulfur battery.

(2) The soluble polysulfide intermediates produced during charging and discharging are easily soluble in the electrolyte, which will lead to the loss of the active substance sulfur, and at the same time, the increase in the viscosity of the electrolyte will lead to a continuous decrease in the conductivity of the ions

(3) During the charge and discharge process, due to the different densities of the intermediates at different stages, the volume of the positive electrode material changes. This volume change can easily lead to a change in the structure of the positive electrode material, resulting in the separation of the active material sulfur from the conductive network skeleton. As a result, the capacity of lithium-sulfur batteries is irreversibly attenuated.

The common defects in the above-mentioned prior art are: the utilization rate of the active material in the composite positive electrode material is low, and the adsorption and transformation ability of polysulfides is weak during the electrochemical reaction process, resulting in poor ability to inhibit the shuttle effect. The prepared lithium-sulfur battery has low specific capacity and poor cycle performance during charge and discharge

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