CN102983321B

CN102983321B - Carbon-coated MnOx nano energy storage material with one-dimensional core-shell structure and preparation method thereof

Info

Publication number: CN102983321B
Application number: CN201210564956.5A
Authority: CN
Inventors: 杨尊先
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2012-12-24
Filing date: 2012-12-24
Publication date: 2015-03-04
Anticipated expiration: 2032-12-24
Also published as: CN102983321A

Abstract

The invention discloses a carbon-coated MnOx nano energy storage material with a one-dimensional core-shell structure and a preparation method thereof. The energy storage material with a one-dimensional core-shell structure, which takes amorphous carbon as a shell and a MnOx nanowire as a core, is prepared by using a hydrothermal method through the processes of suction filtration, ultrasonic treatment, heat treatment, soaking and the like. According to the invention, the preparation processes are simple, and the prepared material has the advantages of high specific surface area, good electrical conductivity, good structure stability and good electrochemical cycle performance, and has a great application potential in the field of negative electrode materials for lithium secondary batteries.

Description

A kind of one dimension core-shell structure carbon coated MnOx nanometer energy storage material and preparation method thereof

Technical field

The invention belongs to new forms of energy nanometer energy storage material field, be specifically related to the coated MnO of a kind of one dimension core-shell structure carbon _xnanometer energy storage material and preparation method thereof.

Background technology

Along with the exhaustion day by day of traditional energy, the lithium rechargeable battery as new forms of energy representative receives increasing concern.Simultaneously as the main power source of portable communication apparatus with portable electric appts, because it has the focus becoming compared with the excellent properties such as high output voltage and high-energy-density and study both at home and abroad.For meeting the demand of high-power, high power capacity communication apparatus and electronic equipment, domestic and international expert is devoted to study the lithium ion battery electrode material with high power capacity, good stability, economy, environmental protection always, wherein manganese oxide material is due to its higher theoretical lithium memory capacity, be considered to a kind of most potential negative material, and be widely studied.

But, as the manganese oxide of negative material because himself conductance is low, heavy-current discharge performance is poor, particularly when high-multiplying power discharge, its voltage platform is on the low side, energy density is less, causes its cycle performance poor, and termination capacity cannot compared with its theoretical capacity.Therefore, in order to improve the electric conductivity of manganese oxide material and its actual capacity in lithium ion battery applications and cycle performance, people are seeking the research how improving its circulating and reversible capacity and electric conductivity always.

There are some researches show its electric discharge theoretical capacity of the effective raising of meeting when the size of manganese oxide material being reduced to Nano grade, also have part research in manganese oxide material, add other materials to be formed and become composite material again, improve its electric conductivity with this, thus also improve its cycle performance.(CN1438181A) provide one in and prepare MnO ₂the preparation method of nano material: adopt potassium permanganate to be raw material material, take alkyl alcohol ethoxylates as reducing agent, surface dispersant and particle size stabilizer, obtain nano-manganese dioxide by redox reaction.Document Chem. Commun., the MnO that 2012,48,6945 – 6947 propose ₂the research of nano wire, their method is by preparing nano thread structure MnO ₂improve MnO ₂as the chemical property of negative material, but do not change the shortcoming of its poor electric conductivity, cyclicity difference.Document Electrochemistry Communications 11 (2009) 795 – 798 proposes electrostatic spinning preparation and has higher consistency MnO ₂@Carbon composite material, effectively improves MnO ₂charge-discharge performance and conductivity, but it prepares equipment needed thereby more complicated, production efficiency is low, and cost is higher.Therefore effectively play synergy in the embedding de-process of lithium of each composition in nano composite material by artificial designing material structure and material composition thus realize composites performance raising etc. and all need research further.

In sum, the material of the manganese oxide mentioned in most of document or patent in theory all can not eliminate the decline of its cycle performance effectively, thus affects the application and development of manganese oxide material in lithium electricity.Meanwhile current preparation method's all more complicated of manganese oxide and other materials compound in patent, and the manganese oxide material specific surface area prepared is limited, poorly conductive, for improving its lithium memory property limited use.

Summary of the invention

The object of the invention is to for shortcomings and deficiencies of the prior art, provide a kind of one dimension core-shell structure carbon coated MnO _xnanometer energy storage material and preparation method thereof, preparation technology is simple, prepared material has the advantage of high-specific surface area, good conductivity, structural stability and electrochemistry good cycle, has huge application potential in lithium secondary battery electrode negative material field.

For achieving the above object, the present invention adopts following technical scheme:

The coated MnO of a kind of one dimension core-shell structure carbon _xthe preparation method of nanometer energy storage material comprises the steps:

(1) hydro thermal method is adopted to prepare MnO ₂nano wire;

(2) prepare the ethanolic solution of 20-40mL macromolecule organic, take the MnO of 0.5-1.5g step (1) ₂nano wire is distributed to wherein, ultrasonic process, filtration, drying, obtains the MnO be distributed in macromolecule organic ₂nano wire;

(3) by the MnO be distributed in macromolecule organic of step (2) ₂nano wire carries out high-temperature heat treatment under protective atmosphere, and cooling, obtains the coated MnO of one dimension core-shell structure carbon _xnanometer energy storage material.

Described MnO _xfor Mn ₃o ₄, MnO ₂, MnO, Mn ₂one or more mixture in O.

The ethanolic solution of the macromolecule organic described in step (2) is the ethanolic solution of polyvinylpyrrolidone (PVP), and its concentration is 0.1-1.5mol/L.

High-temperature heat treatment of carrying out under protective atmosphere described in step (3) refers in the tube furnace being full of argon gas or nitrogen, heats 2-5h at 500-700 DEG C.

The method can make full use of the high capacity characteristics of manganese oxide material in lithium ion battery, and preparing with manganese oxide nano wire is the lithium ion battery negative material of main discharge and recharge material; In addition, overcome the adding of amorphous carbon the deformation in charge and discharge process of manganese oxide nano wire to break and even depart from and the drawback of the electrode material poorly conductive caused, thus obtain a kind of coated MnO of one dimension shell core carbon with high power capacity, higher rate charge-discharge speed and capacity and good circulation performance _xthe preparation method of nano wire energy storage material.

Beneficial effect of the present invention is: ion cathode material lithium prepared by the present invention is a kind of with the coated MnO of amorphous carbon _xone dimension shell core nano thread structure, compared with prior art, this invention owing to successively adopting hydro thermal method and infusion method, not only possessed nano-material high-specific surface area effect but also possess 1-dimention nano functional material structure feature.Meanwhile, with carbon manganese oxide effectively wrapped up and isolate, effectively prevent its reuniting effect in charge and discharge process, and improve the structural stability of composite material, conductivity and cyclicity stability.In addition, present invention process is easy, easy to operate, material composition is easy to regulation and control, is the effective ways that preparation comprises high performance lithium ion battery electrode material nano-functional material.

Accompanying drawing explanation

Fig. 1 is the coated MnO of single one dimension core-shell structure carbon _xthe structural representation of nano wire energy storage material, wherein (1) is shell, (2) be core.

Fig. 2 is MnO ₂the scanning electron microscope (SEM) photograph of nano wire.

Fig. 3 is the MnO be distributed in PVP ₂the scanning electron microscope (SEM) photograph of nano wire.

Fig. 4 is the coated MnO of one dimension core-shell structure carbon _xthe scanning electron microscope (SEM) photograph of nano wire energy storage material.Wherein MnO _xfor Mn ₃o ₄, MnO ₂, MnO, Mn ₂one or more mixture in O.

Embodiment

The present invention aims to provide the coated MnO of a kind of one dimension shell core carbon _xthe preparation method of nano wire energy storage material, shows by reference to the accompanying drawings and concrete execution mode illustrates.

Embodiment 1

1) take that quality is 1.64g five hydration manganese acetate, 1.59g potassium peroxydisulfate, 2.47g ammonium nitrate dissolve in 10ml, 20ml, 10ml deionized water respectively, ultrasonic process 10min, by solution mixing ultrasonic 10min again, transfer to 60ml hydrothermal reaction kettle, be placed in heat treatment 12h at 140 DEG C, baking oven, cooling, uses deionized water, alcohol washes successively, be placed in dry 24h at 50 DEG C, baking oven, obtain MnO ₂nano wire; Fig. 2 is MnO ₂the scanning electron microscope (SEM) photograph of nano wire;

2) take 0.7gPVP to be dissolved in 20ml ethanol, be stirred to homogeneous solution, then take the MnO in 0.5g step 1) ₂nano wire is distributed to PVP ethanolic solution, ultrasonic 2h, after filtration, dry 12h, can obtain the MnO be distributed in PVP ₂nano wire; Fig. 3 is the MnO be distributed in PVP ₂the scanning electron microscope (SEM) photograph of nano wire;

3) take 0.8g step 2) in be distributed in MnO in PVP ₂nano wire is placed in the tube furnace of Ar gas shielded, and 500 DEG C of heat treatment 2h, are cooled to room temperature, can obtain the coated MnO of one dimension core-shell structure carbon _xnano wire energy storage material, wherein MnO _xfor Mn ₃o ₄, MnO ₂, MnO, Mn ₂one or more mixture in O; Fig. 4 is the coated MnO of one dimension core-shell structure carbon _xthe scanning electron microscope (SEM) photograph of nano wire energy storage material.

Embodiment 2

1) take that quality is 2.45 five hydration manganese acetates, 2.38g potassium peroxydisulfate, 2.44g ammonium nitrate dissolve in 10ml, 30ml, 10ml deionized water respectively, be labeled as A, B, C respectively, mix after ultrasonic to A, B, C 10min, transfer in 80ml hydrothermal reaction kettle, be placed in heat treatment 12h at 120 DEG C, baking oven, cooling, after using deionized water, alcohol, deionized water, alcohol washes four times successively, be placed in dry 24h at 75 DEG C, baking oven, namely obtain MnO ₂nano wire;

2) getting 0.8gPVP is dissolved in 25ml ethanol, stirs 1h, then takes the MnO in step 1) ₂nano wire 0.7g is distributed in PVP ethanolic solution, leaves standstill 1h again after ultrasonic 2h, and filtration, drying, obtain the MnO be distributed in PVP ₂nano wire;

3) take 1.0g step 2) in be distributed in MnO in PVP ₂nano wire is placed in the tube furnace under nitrogen protection, 550 DEG C of heat treatment 3h, and cooling, can obtain the coated MnO of one dimension core-shell structure carbon _xnano wire energy storage material, wherein MnO _xfor Mn ₃o ₄, MnO ₂, MnO, Mn ₂one or more mixture in O.

Embodiment 3

1) get 2mmol five hydration manganese acetate respectively, 2mmol potassium peroxydisulfate, 3mmol ammonium nitrate dissolves in 20ml, 35ml, 15ml deionized water respectively, mix after ultrasonic process 10min, transfer to after ultrasonic 10min again in 100ml hydrothermal reaction kettle, with being placed in baking oven heat treatment 12h at 160 DEG C, after cooling, use deionized water, alcohol washes successively, then be placed in dry 48h at 50 DEG C, baking oven, namely obtain MnO ₂nano wire;

2) getting 1.2gPVP is dissolved in 40ml ethanol, then gets the MnO in step 1) ₂nano thread structure material 0.8g, is distributed to wherein when stirring, ultrasonic 2h, filters, dry, obtains the MnO be distributed in PVP ₂nano wire;

3) by step 2) in the MnO be distributed in PVP ₂nano wire under an ar atmosphere in tube furnace in, 600 DEG C of heat treatment 3h, after being cooled to room temperature, can obtain the coated MnO of one dimension core-shell structure carbon _xnano wire energy storage material, wherein MnO _xfor Mn ₃o ₄, MnO ₂, MnO, Mn ₂one or more mixture in O.

The foregoing is only preferred embodiment of the present invention, all equalizations done according to the present patent application the scope of the claims change and modify, and all should belong to covering scope of the present invention.

Claims

1. the coated MnO of one dimension core-shell structure carbon _xnanometer energy storage material, is characterized in that: preparation method comprises the steps:

(1) hydro thermal method is adopted to prepare MnO ₂nano wire;

(3) by the MnO be distributed in macromolecule organic of step (2) ₂nano wire carries out high-temperature heat treatment under protective atmosphere, and cooling, obtains the coated MnO of one dimension core-shell structure carbon _xnanometer energy storage material;

Described MnO _xfor Mn ₃o ₄, MnO ₂, MnO mixture;

The ethanolic solution of the macromolecule organic described in step (2) is the ethanolic solution of polyvinylpyrrolidone, and its concentration is 0.1-1.5mol/L;