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CN-122000319-A - Carbon nano tube-manganese dioxide-graphene composite electrode material for lithium ion battery and preparation method thereof

CN122000319ACN 122000319 ACN122000319 ACN 122000319ACN-122000319-A

Abstract

The invention discloses a carbon nano tube-manganese dioxide-graphene composite electrode material for a lithium ion battery and a preparation method thereof, which belong to the technical field of lithium ion batteries, and the carbon nano tube-manganese dioxide-graphene composite electrode material for the lithium ion battery has a core-branch-hole three-level conductive structure, wherein the innermost layer is a carbon nano tube sponge, a three-dimensional through electron transmission channel is constructed, and a tree shape is arranged along the axial direction of the carbon nano tube sponge Nano-sheet, forming carbon nano-tube- The surface of the manganese dioxide nano sheet is covered with a graphene layer (namely the outermost layer is the graphene nano sheet), a point-to-point physical overlap network is formed, the interface stress is reduced, the electron transmission efficiency is improved, the specific capacity of the carbon nano tube-manganese dioxide-graphene composite electrode material for the lithium ion battery is 100-200 mAh/g, and the capacity retention rate is more than or equal to 80% after the carbon nano tube-manganese dioxide-graphene composite electrode material is cycled for 500 times at 1C.

Inventors

  • CHEN JINMAO
  • AN GAOJUN
  • XU XIMENG
  • SUN YANLI
  • WANG CHANGFU
  • ZHOU YOUJIE
  • HUANG LONG
  • WANG XUDONG
  • XU WANLI
  • SU XING
  • ZHENG ZHE
  • XIA YANGFENG

Assignees

  • 军事科学院系统工程研究院军事新能源技术研究所

Dates

Publication Date
20260508
Application Date
20251229

Claims (10)

  1. 1. A carbon nano tube-manganese dioxide-graphene composite electrode material for a lithium ion battery is characterized by having a three-stage rechecking structure with a core layer, a branch layer and a shell layer, wherein the core layer is a carbon nano tube sponge, the branch layer is manganese dioxide nano sheets arranged along the axial direction of the carbon nano tube sponge, and the shell layer is graphene nano sheets coated on the surface of the manganese dioxide nano sheets.
  2. 2. The carbon nanotube-manganese dioxide-graphene composite electrode material for a lithium ion battery according to claim 1, wherein the porosity of the carbon nanotube sponge is 85-95%, the pore diameter is 100-400 nm, and the density is 0.3-0.5 g- ; And/or the thickness of the manganese dioxide nano-sheet is 10-50 nm; And/or the thickness of the graphene nano sheet is 1-3 layers, and the length and the width of the graphene nano sheet are 100-500 nm.
  3. 3. A method for preparing the carbon nanotube-manganese dioxide-graphene composite electrode material for a lithium ion battery according to any one of claims 1 to 2, comprising the following steps: preparing a carbon nanotube sponge by an ice template method; Depositing manganese dioxide nano sheets on the surface of the carbon nanotube sponge by adopting a double-pulse electrodeposition method; And self-assembling the graphene nano-sheets on the manganese dioxide nano-sheets by a pH response self-assembly method.
  4. 4. The method for preparing the carbon nanotube-manganese dioxide-graphene composite electrode material for the lithium ion battery, according to claim 3, is characterized by comprising the specific steps of mixing a carbon nanotube suspension with an ice template, freezing at-80 ℃ for 12 hours, and removing the ice template by vacuum drying to obtain the carbon nanotube sponge.
  5. 5. The method for preparing a carbon nanotube-manganese dioxide-graphene composite electrode material for a lithium ion battery according to claim 4, wherein the ice crystal size formed in the freezing process is 300-500 nm.
  6. 6. The method for preparing a carbon nanotube-manganese dioxide-graphene composite electrode material for a lithium ion battery according to claim 3, wherein in the process of depositing manganese dioxide nano sheets on the surface of the carbon nanotube sponge by adopting a double-pulse electrodeposition method, the electrodeposition liquid is Sodium acetate and The pH value of the mixed solution is 4-4.5, and the current density of the forward pulse is 0.2-0.6 mA +. The current density of the reverse pulse is-0.3 to-0.1 mA +. The cycle times are 1500-2500 times, and the deposition time is 300-450 min.
  7. 7. The method for preparing a carbon nanotube-manganese dioxide-graphene composite electrode material for a lithium ion battery according to claim 3, wherein the step of self-assembling the graphene nanoplatelets on the manganese dioxide nanoplatelets by a pH response self-assembly method comprises the steps of immersing a carbon nanotube sponge with the manganese dioxide nanoplatelets deposited on the surface thereof in a graphene oxide solution with an initial pH of=2, standing, and adjusting the pH of the solution to be=10.
  8. 8. The method for preparing a carbon nanotube-manganese dioxide-graphene composite electrode material for a lithium ion battery according to claim 7, wherein the concentration of the graphene oxide solution is 5-8 mg/mL; And/or standing for 120-300 min.
  9. 9. Use of the carbon nanotube-manganese dioxide-graphene composite electrode material for lithium ion batteries according to any one of claims 1-2 in preparation of lithium ion batteries.
  10. 10. The use of claim 9, wherein the lithium ion battery comprises a liquid lithium ion battery, a gel state lithium ion battery, and a solid state lithium ion battery.

Description

Carbon nano tube-manganese dioxide-graphene composite electrode material for lithium ion battery and preparation method thereof Technical Field The invention belongs to the technical field of lithium ion batteries, and particularly relates to a carbon nano tube-manganese dioxide-graphene composite electrode material for a lithium ion battery and a preparation method thereof. Background In the field of Lithium Ion Batteries (LIB), the performance improvement of the positive electrode material is a key to breaking through the energy density and cycle life bottlenecks. Manganese dioxide [ ]) The cathode material has high theoretical specific capacity (308 mAh/g), low cost and environmental friendliness, and becomes a potential cathode candidate material. However, its material properties limit its practical application in the field of lithium batteries,Has at least the following disadvantages: (1) Poor conductivity: Intrinsic conductivity is extremely low ~S/cm), resulting in low efficiency of charge transport therein, and difficulty in achieving high power density. (2) The structural stability is insufficient, in the charge and discharge process,The volume expansion is easy to cause structural collapse, resulting in short cycle life. (3) The interface resistance is high-in the conventional electrode material,Insufficient physical contact with a conductive agent (such as carbon black), and high interface contact resistance, further reduces the electrochemical performance. Although one skilled in the art would attempt to coat by grapheneConstructing nanocomposite structures to improve their conductivity, but three-dimensional conductive networks of single carbon materials have limited ability to construct, andThe uniform growth and interface bonding of nanoplatelets still lacks effective means of regulation. Therefore, electrode composite materials with high conductivity, structural stability and interface compatibility are developed, and are used for improving lithium ionsThe core challenge of the performance of the base electrode composite material. Disclosure of Invention To solve the existing problemsThe invention provides a carbon nano tube-manganese dioxide-graphene composite electrode material for a lithium ion battery and a preparation method thereof, wherein the carbon nano tube-manganese dioxide-graphene composite electrode material for the lithium ion battery has a core-branch-hole three-level conductive structure, and the lithium ion battery with high power density, high energy density and long cycle life is prepared through multi-scale structural design and synergistic effect. In order to achieve the above purpose, the present invention provides the following technical solutions: The carbon nano tube-manganese dioxide-graphene composite electrode material for the lithium ion battery is of a three-stage rechecking structure composed of a core layer, a branch layer and a shell layer, wherein the core layer is a carbon nano tube sponge, the branch layer is manganese dioxide nano sheets arranged along the axial direction of the carbon nano tube sponge, and the shell layer is graphene nano sheets coated on the surface of the manganese dioxide nano sheets. Further, the porosity of the carbon nanotube sponge is 85-95%, the pore diameter is 100-400 nm, and the density is 0.3-0.5 g-; And/or the thickness of the manganese dioxide nano-sheet is 10-50 nm; And/or the thickness of the graphene nano sheet is 1-3 layers, and the length and the width of the graphene nano sheet are 100-500 nm. The invention also provides a preparation method of the carbon nano tube-manganese dioxide-graphene composite electrode material for the lithium ion battery, which comprises the following steps: preparing a carbon nanotube sponge by an ice template method; Depositing manganese dioxide nano sheets on the surface of the carbon nanotube sponge by adopting a double-pulse electrodeposition method; And self-assembling the graphene nano-sheets on the manganese dioxide nano-sheets by a pH response self-assembly method. Further, the specific steps of preparing the carbon nanotube sponge by the ice template method are that the carbon nanotube suspension is mixed with the ice template, frozen for 12 hours at the temperature of-80 ℃, and the ice template is removed by vacuum drying, so that the carbon nanotube sponge is obtained. Further, the ice crystal size formed in the freezing process is 300-500 nm. Further, in the process of depositing manganese dioxide nano-sheets on the surface of the carbon nanotube sponge by adopting a double-pulse electrodeposition method, the electrodeposition liquid isSodium acetate and NaThe pH value of the mixed solution is 4-4.5, and the current density of the forward pulse is 0.2-0.6 mA +.The current density of the reverse pulse is-0.3 to-0.1 mA +.The cycle times are 1500-2500 times, and the deposition time is 300-450 min. Further, the step of self-assembling the graphene nano-sheets on the manganese diox