Perovskite KTaO3 potassium ion battery negative electrode material synthesized by electric field control and crystallization selection and preparation method thereof

Abstract

The invention relates to a perovskite KTaO3 potassium ion battery negative electrode material synthesized by electric field control and crystallization selection and a preparation method thereof. The perovskite KTaO3 potassium ion battery negative electrode material is characterized in that the crystallization characteristic of a crystal with lattice defect is changed by applying an electric field in a special direction during high-temperature solid-phase reaction, columnar-appearance particles are grown and formed along a direction of the electric field, and meanwhile, a part of a sintering additive which is non-uniformly pasted on a large part of a surface curvature radius are bonded to form continuous and porous morphology due to non-uniform crystallization on surfaces of columnar-appearance particles. By such morphology, the gain boundary resistance is favorably reduced, the moving capability of potassium ions in lattices is improved, a continuous electron transfer network is formed, the electron transfer resistance is reduced, the contact area with an electrolyte is expanded, and the transfer capability of the potassium ions in the electrolyte and the lattices and the oxidization-reduction reaction ratio are improved; and such structure also has certain structural rigidity, buffer is formed for volume deformation of a material during the charge-discharge process, so that the high-performance potassium ion battery negative electrode material is formed.

Description

technical field [0001] The invention relates to the technical field of a high-performance perovskite composite potassium ion battery negative electrode material manufacturing method. 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 ...

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 type perovskite structure oxide is alloyed, it can react with two metals, and it may produce alloy solid solutions in various phases. Due to the interaction of bimetals, it may also produce a completely different electric current from that of single metals. Chemical properties, therefore ABO 3 Type perovskite structure 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 a 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, etc.

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