Continuous electron ion quick conductive double-perovskite negative electrode material of potassium ion battery and preparation method for negative electrode material

Abstract

Disclosed are a continuous electron ion quick conductive double-perovskite negative electrode material of a potassium ion battery and a preparation method for the negative electrode material. The negative electrode material is characterized by comprising KTb<0.5>Ba<0.2>Y<0.2>Li<0.1>Zr<0.8>Fe<0.1>Zn<0.1>NbO<6>; in the preparation process, a continuous pore channel structure of gel is taken as a template to form a continuous porous appearance double-perovskite structured product with bonded particle parts; meanwhile, a continuous high-conductivity carbon film attached to the surface of the active material is formed through cracking under a protective gas; by virtue of such appearance, crystal boundary resistance can be lowered; a continuous electron transfer network is formed and electron transfer resistance is lowered; a contact area with an electrolyte is enlarged, and certain structural rigidity is achieved; furthermore, through co-occupation of K and Tb in A position and through partial Ba, Y and Li replacement in a Tb position, electron conductivity is improved; and by virtue of Fe and Zn doping in a B position, the perovskite structural stability is improved, and the high-performance negative electrode material of the potassium ion battery can be finally formed.

Description

technical field [0001] The invention relates to the technical field of a method for manufacturing an anode material of a potassium ion battery. Background technique [0002] Lithium-ion secondary batteries have the absolute advantages of high volume, weight-to-energy ratio, high voltage, low self-discharge rate, no memory effect, long cycle life, and high power density. Currently, the global mobile power market has an annual share of more than 30 billion US dollars and Gradually grow at a rate of more than 10%. Especially in recent years, with the gradual depletion of fossil energy, new energy sources such as solar energy, wind energy, and biomass energy have gradually become alternatives to traditional energy sources. Among them, wind energy and solar energy are intermittent, and a large amount of energy is used simultaneously to meet the needs of continuous power supply. Energy storage batteries; urban air quality problems caused by automobile exhaust are becoming more an...

AI Technical Summary

Problems solved by technology

However, it is still very difficult to take into account the rate performance and cycle capacity retention performance of the material.

The main reasons are as follows: 1. When the redox reaction occurs, the electrode material should have fast lithium ion intercalation and deintercalation and electronic conduction, that is, it should have good electronic conductivity and ion conductivity at the same time. Many negative electrode materials have high However, it is an electronic insulator, and some negative electrode materials are good electronic conductors, but the diffusion capacity of lithium ions is weak, which greatly increases the polarization of the battery; 2. Many electrode materials are intercalated with lithium ions and There is a large volume change during the deintercalation process, resulting in the breakage of electrode material particles and the loss of effective electrode materials during the cycle. The large volume change also brings about the transformation of the material lattice during the charging and discharging process to produce a second phase. seriously affect the performance of the battery

3. Lithium battery negative electrode material with conversion reaction mechanism, the electronic insulation of the reaction product lithium compound seriously affects the reversibility of the material

ABOs 3 When the alloy reaction is carried out, the oxide can react with two metals, which may produce alloy solid solutions in various phases. Due to the interaction of bimetals, it may also produce electrochemical characteristics that are completely different from those of single metals. Therefore, ABOs 3 Type oxides may become a high-performance potassium-ion battery anode material, which may provide close to or more than 300mAh.g -1 The specific capacity, the volume change of the material that potassium ions enter or exit is also small; however, the research and development of this material in potassium ion batteries is basically blank

And its main problem is: 1, ionic conductivity and electron conductivity are lower; 2, the product potassium oxide after conversion reaction is electronic insulator and its potassium ion diffusion activation energy is also higher, causes larger electrochemical polarization; 3. The synthesis temperature is high, which is easy to cause the growth and agglomeration of grains

[0014] In response to these problems, changing the shape of the material can alleviate these problems to a certain extent. For example, reducing the particle size of the material to the nanometer scale can reduce the diffusion path of potassium ions, shorten the diffusion time of potassium ions, and improve the kinetics of the material. Performance; too small particle size can easily cause difficulties in electronic conduction between particles; the same agglomeration between particles or too large particles can easily cause electrolyte penetration difficulties between particles, slow migration of potassium ions and other problems; ion doping Doping is also an effective way to adjust the microstructure of the lattice and change the transport characteristics of lattice electrons and ions. However, the mechanism of ion doping or even multi-ion synergistic doping on the matrix is ​​very complicated, and the effect is often unpredictable.

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