NiS/graphene and carbon composite material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of lithium ion battery electrode materials, in particular to a NiS / graphene and carbon composite material and a preparation method and application thereof. Nickel sulfide, graphene oxide and a carbon source are compounded, porous carbon is obtained after gel carbonization, the porous carbon has a large specific surface area, and attachment of graphene oxide and nickel sulfide is achieved; the porous carbon has a cross-linked pore structure, and after the porous carbon is compounded with the nickel sulfide, the nickel sulfide is attached to the porous carbon, so that the synergistic effect of the nickel sulfide and the porous carbon is improved, and the conductivity is further improved; the porous carbon is adopted to replace graphene, under the combined action of the reduced graphene oxide, the nickel sulfide and the porous carbon, the conductivity of the electrode material is close to that of a NiS-graphene material, and then the electrode material with excellent conductivity is obtained while the use amount of the graphene is reduced and the cost is saved to a certain extent.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery electrode materials, and specifically relates to a NiS / graphene@carbon composite material and its preparation method and application. Background technique [0002] Due to the advantages of high working voltage, small size, light weight, high energy, no memory effect, no pollution, small self-discharge, and long cycle life, lithium-ion batteries are gradually developed as ideal energy sources; lithium-ion batteries are a A rechargeable battery works by intercalating and deintercalating lithium ions back and forth between the positive electrode and the negative electrode. When charging, lithium ions are deintercalated from the positive electrode, and then intercalated into the negative electrode through the electrolyte. At this time, the negative electrode is in a lithium-rich state, and the opposite is true when discharging. , it can be seen that in order to improve and optimize the ele...

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Problems solved by technology

[0003] Nickel sulfide (NiS, Ni 3 S 2 、NiS 2 、Ni 3 S 4 etc.) belong to narrow-bandgap transition metal semiconductors, and its nanoparticles are a typical transition metal chalcogenide with high specific capacity, excellent conductivity, abundant reserves, low price, and easy processing and preparation. It is a potential Lithium-ion battery electrode materials; compared with carbon materials, sulfur in nickel sulfide can react reversibly with lithium metal, which provides reversible capacity. The process is: Ni x S y +2yLi→xNi+yLi 2 S; although this reaction can provide a higher capacity, due to the large volume change in the lithium intercalation process, the active material of the electrode falls off from the current collector, causing a rapid decline in capacity, and at the same time, pure nickel sulfide nanoparticles are easy to agglomerate and Poor electrical conductivity and poor recycling performance greatly limit its performance

[0004] The prior art uses graphene to technically modify nickel sulfide to obtain a graphene@nickel sulfide composite material. However, because graphene used in electrode materials is generally expensive, the resulting graphene@nickel sulfide composite material is not conducive to industrialization. Promotion of production, so its application is limited, so the research in the prior art is still aimed at the modification of carbon materials by graphene, in order to achieve the improvement and promotion of the electrical properties of electrode materials

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