Microwave hydrothermal synthesizing method for carbon nanotube/LiFePO4 lithium ion battery anode material

Abstract

The invention provides a microwave hydrothermal synthesizing method for carbon nanotube / LiFePO4 lithium ion battery anode material. The method comprises the following steps of respectively adding LiOH*H2O or Li2CO3 and NH4H2PO4 and FeC2O4*2H2O in deionized water, obtaining solution A; adding citric acid into the solution A, obtaining solution B; dispersing carbon nanotube (CNT) in concentrated HNO3 for soaking, and ultrasonic washing the CNT, obtaining purified CNT; adding the purified CNT in the solution B, obtaining reaction liquid; pouring the reaction liquid in a microwave hydrothermal kettle, sealing the microwave hydrothermal kettle, placing the sealed microwave hydrothermal kettle in a temperature and pressure doubly-controlled microwave hydrothermal reaction instrument for reacting, after the reaction is finished, naturally cooling the reactant to a room temperature, performing centrifugal separation for the reactant, washing the reactant by deionized water and absolute ethyl alcohol respectively, and then drying the reactant in a vacuum drying box, obtaining the carbon nanotube / LiFePO4 lithium ion battery anode material. According to the method provided by the invention, the microwave method and hydrothermal method are combined, so that the preparation of LiFePO4 lithium ion compound battery power body can be finished in the liquid phase at one step, the operation is simple, subsequent annealing heat treatment is not required, the reaction temperature is low, the reaction period is short, and the energy consumption is small, and moreover, the preparation cost of apower body can be reduced.

Description

technical field [0001] The invention relates to a carbon nanotube / LiFePO 4 A preparation method for lithium-ion battery nanopowder, in particular to a carbon nanotube / LiFePO 4 Microwave hydrothermal synthesis method of cathode material for lithium ion battery. technical background [0002] LiFePO 4 It has an olivine structure and can reversibly intercalate and deintercalate lithium ions. At the same time, it has the advantages of high energy density, stable performance, high safety, environmental friendliness and cheaper price. The theoretical specific capacity of this material is 170mAh / g -1 , has a flat and moderate discharge platform (about 3.4V) relative to the lithium metal negative electrode, so it is considered to be the most potential positive electrode material for lithium-ion batteries. But pure LiFePO 4 There is a disadvantage determined by the crystal structure: the electrical conductivity is small (about 10 -9 S / cm), low ion diffusion coefficient (about 1...

AI Technical Summary

Problems solved by technology

But pure LiFePO 4 There is a disadvantage determined by the crystal structure: the electrical conductivity is small (about 10 -9 S / cm), low ion diffusion coefficient (about 10 -11 ~10 -10 S / cm), leading to a sharp drop in its discharge capacity at high current densities, and poor cycle performance, limiting LiFePO 4 Applications

The above method uses carbon nanotubes to effectively improve the electrochemical performance of the powder, and the mass specific capacity and cycle performance have been greatly improved. However, due to the insolubility and agglomeration of CNTs, it is not easy to disperse, and so far LiFePO 4 There are few studies on wet mixing with CNT

Images