High-thermal-conductivity flexible graphene composite material and preparation method therefor, and lithium ion battery

Abstract

The invention relates to a preparation method for a high-thermal-conductivity flexible lithium ion battery negative electrode graphene composite material. The preparation method comprises the following steps of enabling a graphite rod to be soaked in an inorganic salt solution to be fully wetted; taking the graphite rod as the positive electrode, taking a platinum sheet electrode as the negative electrode, and taking the inorganic salt solution as the electrolyte to be assembled into an electrolytic tank system, and applying a constant voltage between the negative electrode and the positive electrode to carry out electrochemical stripping; taking out the positive electrode and the negative electrode, and carrying out ultrasonic processing on the electrolyte; centrifuging the electrotype, taking the upper layer liquid to obtain a graphene/SnO<2> compound aqueous solution; and carrying out suction filtration on the graphene/SnO<2> compound aqueous solution to obtain the graphene composite material, wherein the inorganic salt solution is selected from one kind of a sodium stannate solution and a potassium stannate solution. The invention also provides the high-thermal-conductivity flexible lithium ion battery negative electrode graphene composite material and a lithium ion battery. The high-thermal-conductivity flexible lithium ion battery negative electrode graphene composite material and the lithium ion battery are relatively high in thermal dissipation and stability.

Description

technical field [0001] The invention relates to the technical field of lithium battery electrodes, in particular to a highly thermally conductive flexible lithium ion battery negative electrode graphene composite material, a preparation method thereof, and a lithium ion battery. Background technique [0002] Lithium-ion batteries have excellent comprehensive properties such as high working voltage, high energy density, long cycle life, light weight, and small self-discharge. As a new energy storage device for renewable energy, they are clean and pollution-free, and have been highly valued by governments in recent years. , has become one of the research hotspots and has developed rapidly in recent years. As the most potential driving energy for electric vehicles and hybrid vehicles in the future, lithium-ion batteries must have higher energy density, power density and good cycle stability. Anode materials are one of the key factors limiting the development of lithium-ion bat...

AI Technical Summary

Problems solved by technology

Anode materials are one of the key factors limiting the development of lithium-ion batteries. In recent years, researchers have developed some high-performance anode materials, such as Si, Sn and other metals, SnO 2 , Fe 2 o 3 transition metal oxides, etc., but these negative electrode materials are facing a serious problem that the active material breaks or falls off from the pole piece due to the huge volume expansion and agglomeration of the active material during the cycle, resulting in pulverization, which deactivates the active material, and then Cycle life drops rapidly

[0003] In order to solve the problem of pulverization of negative electrode materials in the process of charging and discharging and further improve the structural stability of electrode materials, it is proposed to use nanostructures or special design structures to solve these problems, such as (1) design hollow nanostructures to buffer The problem of volume expansion, but the hollow structure reduces the volume density of the electrode. (2) Carbon coating technology is used to limit the volume expansion of the material and improve the conductivity of the active material. However, the carbon layer tightly coated on the surface of the material It is not the most suitable method to improve the huge volume expansion of the material. At the same time, the carbon layer on the surface of the active material also increases the diffusion distance of the electrolyte ions, which affects the improvement of the power density of the electrode material.

[0004] In addition, lithium-ion batteries will also generate a lot of heat during charging and discharging. If the heat cannot be dissipated in time, it will definitely affect the performance of the battery.

The traditional heat dissipation method of the battery is generally to add some radiators and other devices around the battery or reduce the area of ​​the electrode, etc., but these methods cannot dissipate the heat in a timely and effective manner.

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