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CN-122025560-A - Flexible composite sodium metal negative electrode, preparation method thereof, sodium ion battery and electric equipment

CN122025560ACN 122025560 ACN122025560 ACN 122025560ACN-122025560-A

Abstract

The application provides a flexible composite sodium metal negative electrode, a preparation method thereof, a sodium ion battery and electric equipment, and relates to the field of sodium ion batteries. The method comprises the steps of carrying out acid leaching on a metal framework to obtain a treated framework, carrying out first mixing and electrifying treatment on the treated framework and first alkali liquor to obtain a copper hydroxide coated framework, carrying out annealing treatment and heat treatment on the copper hydroxide coated framework in sequence under reducing gas to obtain a copper nanowire coated metal framework, carrying out second mixing and reaction on the copper nanowire coated metal framework, tartaric acid, bismuth nitrate and water, then adopting second alkali liquor and water for cleaning to obtain a bismuth modified sodium-philic three-dimensional metal framework, and injecting molten sodium metal or carrying out electrochemical deposition on sodium metal on the bismuth modified sodium-philic three-dimensional metal framework to obtain the flexible composite sodium metal cathode. The method has the advantages of wide raw material sources, simple operation, good repeatability, low cost, contribution to large-scale production and the like, and has high possibility of practical application.

Inventors

  • TAN HONGMING
  • FENG JUN
  • HUANG JINGYU
  • XIE YUQIANG
  • LUO XINGHUAI

Assignees

  • 深圳为方能源科技有限公司

Dates

Publication Date
20260512
Application Date
20260304

Claims (10)

  1. 1. The preparation method of the flexible composite sodium metal anode is characterized by comprising the following steps of: Carrying out acid leaching on the copper-containing metal framework to obtain a treated framework; Carrying out first mixing and electrifying treatment on the treated framework and the first alkali liquor to obtain a framework coated with copper hydroxide; sequentially carrying out annealing treatment and heat treatment on the copper hydroxide coated framework under reducing gas to obtain a copper nanowire coated metal framework; Coating the copper nanowire with a metal framework, tartaric acid, bismuth nitrate and water for second mixing and reaction, and then adopting second alkali liquor and water for cleaning to obtain a bismuth-modified sodium-philic three-dimensional metal framework; And injecting molten sodium metal or electrochemically depositing sodium metal into the bismuth-modified sodium-philic three-dimensional metal framework to obtain the flexible composite sodium metal anode.
  2. 2. The method of manufacturing a flexible composite sodium metal negative electrode according to claim 1, wherein the copper-containing metal skeleton comprises copper and/or copper-tin alloy; And/or the shape of the copper-containing metal skeleton comprises at least one of metal foil, net shape and porous foam shape; And/or the porosity of the copper-containing metal framework is 85-95%, and the pore diameter is 100-300 mu m.
  3. 3. The method for producing a flexible composite sodium metal anode according to claim 1, wherein the mass fraction of the acid in the acid leaching is 1 to 10%; And/or the acid in the acid leaching comprises at least one of acetic acid, oxalic acid, sulfuric acid, nitric acid and hydrochloric acid; The pickling time is 30-120min; the mass fraction of the first alkali liquor is 0.1-5 mol/L; And/or, the first alkali liquor comprises sodium hydroxide and/or potassium hydroxide; And/or, the second base solution comprises a sodium carbonate solution.
  4. 4. The method for producing a flexible composite sodium metal anode according to claim 1, wherein the current density of the energization treatment is 0.01 to 1A/cm -2 ; And/or the time of the electrifying treatment is 1-200min.
  5. 5. The method for preparing a flexible composite sodium metal anode according to claim 1, wherein the annealing treatment is performed at an end temperature of 200-500 ℃ for 30-120min; And/or the end point temperature of the heat treatment is 400-700 ℃ and the time is 120-240min.
  6. 6. The method for preparing a flexible composite sodium metal anode according to claim 1, wherein the molar ratio of the tartaric acid to the bismuth nitrate is 0.1-1.5:60-130; And/or the pH value of the mixed solution obtained by the tartaric acid, the bismuth nitrate and the water is 2-7; and/or the reaction time is 1-120 min.
  7. 7. A flexible composite sodium metal negative electrode, characterized in that it is prepared by the method for preparing a flexible composite sodium metal negative electrode according to any one of claims 1 to 6.
  8. 8. A sodium ion battery comprising the flexible composite sodium metal anode of claim 7.
  9. 9. The sodium ion battery of claim 8, wherein the sodium ion battery further comprises a positive electrode, a separator, and an electrolyte; The positive electrode material in the positive electrode comprises at least one of sodium vanadium phosphate, sodium copper iron manganate, prussian white, sodium ferric pyrophosphate, sodium ferric sulfate, sodium nickel iron manganate and sulfur; The membrane comprises at least one of a glass fiber membrane, a polyethylene membrane, a polypropylene membrane, a polyethylene-polypropylene membrane, an aramid membrane, a cellulose membrane, a polyamide membrane and a spandex membrane; The electrolyte comprises an ester electrolyte and/or an ether electrolyte.
  10. 10. A powered device comprising the sodium ion battery of claim 9.

Description

Flexible composite sodium metal negative electrode, preparation method thereof, sodium ion battery and electric equipment Technical Field The application relates to the field of sodium ion batteries, in particular to a flexible composite sodium metal negative electrode, a preparation method thereof, a sodium ion battery and electric equipment. Background The rapid development of technology has led to an increasing demand for consumer electronics, electric vehicles, energy storage, etc., which has driven the further development of rechargeable secondary batteries. Lithium Ion Batteries (LIBs) have been the dominant force in the field of rechargeable secondary batteries because of their ultra-high energy density and cycle life, and widely exist in every corner of life, however, the problem of lithium resource shortage has become a focus of social concern, and a new secondary use for solving the problem of lithium resource shortage is urgently needed. Sodium-based batteries, such as Sodium Ion Batteries (SIBs) and Sodium Metal Batteries (SMBs), are considered to be the best replacement for LIBs, particularly in the low temperature and energy storage fields. Wherein the Na content in the crust is 2.74% which is 400 times of the Li content. And sodium metal is used as a battery cathode, has extremely high energy density 1166 mAh/g and extremely low electrochemical potential-2.71V (compared with a standard hydrogen electrode), and can form SMB with ultra-high energy density when matched with a sodium-free anode. However, in practical applications, sodium metal still faces many problems as a battery anode, such as sodium dendrite growth caused by non-uniform deposition of sodium ions, which can lead to repeated cracking and reformation of solid electrolyte film (SEI) on the anode surface, resulting in loss of active sodium and continuous consumption of electrolyte. And, infinite sodium dendrite growth eventually pierces the separator, causing internal short circuit of the battery, explosion and fire, causing serious safety accidents. In addition, the sodium dendrites are broken and broken in the growth process, so that sodium metal falls off from the substrate to form dead sodium, and the problems of reduction of active sodium, volume expansion and the like are caused. The existence of a plurality of problems seriously affects the cycle life and the safety of the battery and hinders the practical application process of the SMB. In the prior art, most of the composite sodium metal cathodes are synthesized by taking carbon materials as frameworks. Compared with a metal matrix, the carbon matrix is poor in conductivity, affects the rate capability of the battery, is easy to cause the growth of sodium dendrites due to uneven local current density distribution, is low in mechanical strength, is easy to crack in the circulating process and affects the circulating service life, and is high in interface impedance due to the fact that carbon is sodium-repellent, sodium ions are unevenly deposited, and is low in volume expansion adaptability. Finally, the electrode has poor flexibility, is difficult to cope with complex and changeable use environments, has complex manufacturing flow and high process cost, and has great limitation. Based on this, there is a need to provide a method for preparing a flexible composite sodium metal anode to solve the above problems. Disclosure of Invention The application aims to provide a flexible composite sodium metal negative electrode, a preparation method thereof, a sodium ion battery and electric equipment, so as to solve the problems of sodium dendrite growth, dead sodium generation and serious volume expansion caused by uneven deposition of sodium ions in the circulation process, thereby effectively improving the circularity and safety of SMB and providing an effective modification strategy for the practical application of SMB. To achieve the above object, a first aspect of the present application provides a method for preparing a flexible composite sodium metal anode, comprising: Carrying out acid leaching on the copper-containing metal framework to obtain a treated framework; Carrying out first mixing and electrifying treatment on the treated framework and the first alkali liquor to obtain a framework coated with copper hydroxide; sequentially carrying out annealing treatment and heat treatment on the copper hydroxide coated framework under reducing gas to obtain a copper nanowire coated metal framework; Coating the copper nanowire with a metal framework, tartaric acid, bismuth nitrate and water for second mixing and reaction, and then adopting second alkali liquor and water for cleaning to obtain a bismuth-modified sodium-philic three-dimensional metal framework; And injecting molten sodium metal or electrochemically depositing sodium metal into the bismuth-modified sodium-philic three-dimensional metal framework to obtain the flexible composite sodium metal anode. Optionally, the c