CN101335346A - Supercapacitor-battery positive electrode material and preparation method thereof - Google Patents

Abstract

The invention discloses a positive electrode material for a supercapacitor-battery and a preparation method thereof. Nano-scale compound material powder with lithium intercalation characteristics is mechanically fused and granulated to form spherical particles of 1 to 15 microns; 10% to 100% of the porous carbon material by weight of the lithium-intercalation characteristic compound material is mechanically fused to obtain a porous carbon-coated and deintercalated lithium compound composite material. The process of the invention is simple, and the prepared material has both the large-capacity characteristics of battery materials and the high-power characteristics of capacitor materials. Its storage capacity can reach 100mAh/g, and its 10C discharge capacity can reach 90% of 0.5C discharge capacity. Electrode material for new energy storage systems used in automobiles.

Description

Supercapacitor-battery positive electrode material and preparation method thereof

technical field

The invention relates to the field of electrode materials for electrochemical energy storage systems, in particular to positive electrode materials for supercapacitor-batteries.

Background technique

Lithium-ion power batteries are gradually becoming mature. They have high energy density, but their high-current discharge performance still cannot meet the needs of electric tools. The power density of a supercapacitor is dozens or even hundreds of times that of an ordinary battery, but its energy density is only 1/10 of that of a lithium-ion battery, and it cannot be used alone as a vehicle power supply.

Therefore, it has been proposed to combine lithium-ion batteries and supercapacitors, that is, supercapacitor-battery systems. At present, the main combination method is an "external combination", that is, the two monomers are combined into an energy storage system through the power management system, and one of the monomers is allowed to play a role according to the needs of different time periods. What is more ideal is to combine the two organically in the same monomer through the "internal combination", which will be more convenient and effective in use and control. In 2004, Japan's Fuji Heavy Industries proposed lithium-ion battery capacitor (LIC) technology, claiming that it can not only obtain a large current output comparable to that of an electric double-layer capacitor, but also ensure a higher energy density like a lithium-ion rechargeable battery. Xia Yongyao in 2005 (CN 1674347) proposed a hybrid aqueous lithium-ion battery that combines the intercalation-deintercalation mechanism of lithium ions and the electric double layer mechanism of electrochemical capacitors, in which LiMn ₂ O ₄ Such as lithium ion battery cathode material and activated carbon material as electrode. If the material with lithium ion intercalation-deintercalation mechanism and the carbon material with electrochemical capacitor electric double layer mechanism can be combined in a certain way, and the organic electrolyte is used, the system will have high voltage and high voltage at the same time. Energy density, high power density, good cycle life and other advantages.

Contents of the invention

The object of the present invention is to prepare a positive electrode material used in a supercapacitor-battery and a preparation method thereof. This material will combine the high-capacity characteristics of battery materials and the high-power characteristics of capacitor materials.

The technical scheme of the present invention is: put the nano-scale compound material powder with the characteristics of lithium intercalation and deintercalation into mechanical fusion equipment, perform mechanical fusion granulation, and form spherical particles of 1 to 15 microns; 10% to 100% of the weight of the porous carbon material is mechanically fused, and the porous carbon material is uniformly coated on the surface of the lithium intercalation compound material particles to obtain a porous carbon coated lithium intercalation compound composite material. The compound material with lithium intercalation characteristics is selected from one of LiCoO ₂ , LiMn ₂ O ₄ , LiNi _1/3 Mn _1/3 Co _1/3 O ₂ , LiNi _1/2 Mn _1/2 O ₂ , LiFePO ₄ kind. The porous carbon material refers to one or more of activated carbon, mesoporous carbon, carbon nanotube, carbon fiber, and carbon aerogel.

The invention adopts a simple, convenient, and easy-to-control mechanical fusion process to prepare composite material particles having both the large-capacity characteristics of battery materials and the high-power characteristics of capacitor materials. The storage capacity can reach 100mAh/g, and the 10C discharge capacity can reach 0.5 90% of the discharge capacity of C, applying it as an electrode material to a supercapacitor-lithium-ion battery will hopefully become a new energy storage system for electric vehicles.

Description of drawings

Fig. 1. XRD pattern of the LiCoO ₂ /activated carbon composite material prepared by Example 1

Figure 2. SEM image of LiCoO ₂ /activated carbon composite material prepared according to Example 1

Fig. 3. XRD figure of LiNi _1/3 Mn _1/3 Co _1/3 O ₂ / mesoporous carbon composite material prepared by embodiment 2

Fig. 4. SEM image of LiNi _1/3 Mn _1/3 Co _1/3 O ₂ / mesoporous carbon composite material prepared according to Example 2

Figure 5. The initial charge and discharge curves of the LiNi _1/3 Mn _1/3 Co _1/3 O ₂ /mesoporous carbon composite obtained in Example 2

Figure 6. The second charge and discharge curve of the LiFePO ₄ /carbon fiber composite material prepared in Example 3

Figure 7. The discharge rate performance diagram of the LiFePO ₄ /carbon fiber composite material prepared in Example 3

Figure 8. The cycle performance diagram of the LiFePO ₄ /carbon fiber composite material prepared in Example 3 (current density 1.5A/g)

Detailed ways

Example 1

Put nano-scale LiCoO ₂ into mechanical fusion equipment for mechanical fusion granulation to form uniform spherical particles with a size of about 10 microns; then add 10% of its weight of activated carbon, and then perform mechanical fusion treatment. The XRD of the obtained composite material is shown in the figure 1. See Figure 2 for SEM. The material was used as the positive electrode, the metal lithium sheet was used as the negative electrode, and LiPF ₆ /EC+DEC was used as the electrolyte to assemble a battery. The discharge capacity was tested. The discharge specific capacities at 0.5C and 10C were 95mAh/g and 85mAh/g, respectively.

Example 2

Put nano-LiNi _1/3 Mn _1/3 Co _1/3 O ₂ into mechanical fusion equipment, carry out mechanical fusion granulation, and form spherical particles with a size of about 8 microns; then add 50% of its weight of mesoporous carbon, and then carry out Mechanical fusion, the XRD of the obtained composite material is shown in Figure 3, and the SEM is shown in Figure 4. Using this material as the positive electrode, the metal lithium sheet as the negative electrode, and LiPF ₆ /EC+DEC as the electrolyte, the battery was assembled into a battery. The first charge and discharge curves are shown in Figure 5. The discharge specific capacities at 0.5C and 10C are 102mAh/g and 88mAh/ g.

Example 3

Put nano-LiFePO ₄ into mechanical fusion equipment for mechanical fusion granulation to form spherical particles with a uniform size of about 5 microns; then add carbon fiber with 100% weight of lithium iron phosphate, and then perform mechanical fusion treatment to obtain a composite material with The material is the positive electrode, the metal lithium sheet is the negative electrode, and LiPF ₆ /EC+DEC is the electrolyte to assemble the battery. The second charge-discharge curve is shown in Figure 6, and the rate performance is shown in Figure 7. The discharge ratios of 0.5C, 5C and 10C The capacities are 101mAh/g, 96mAh/g and 92mAh/g respectively. The cycle performance (10C) is shown in Figure 8, and the capacity retention rate after 50 cycles is 97%.

Claims (2)

1. anode material for super capacitor battery is characterized in that: this material is by mechanical fusion method porous carbon material to be coated on 1～15 micron the spherical granular material that removal lithium embedded compound composite material surface obtains; Described compound-material with removal lithium embedded characteristic is selected from LiCoO ₂, LiMn ₂O ₄, LiNi _1/3Mn _1/3Co _1/3O ₂, LiNi _1/2Mn _1/2O ₂, LiFePO ₄In a kind of; Described porous carbon material is meant one or more in active carbon, mesopore charcoal, carbon nanotube, charcoal fiber, the charcoal-aero gel.

2. preparation methods as claimed in claim 1 is characterized in that comprising the steps: nano level compound-material powder with removal lithium embedded characteristic is put into mechanical fusion device, carries out machinery and merges granulation, forms 1～15 micron spheric granules; Add consumption and be 10%～100% porous carbon material of removal lithium embedded characterization laminate material weight, carrying out machinery again merges, porous carbon material evenly is coated on the surface of spherical removal lithium embedded compound-material particle, obtains porous charcoal and coat the removal lithium embedded compound composite material; Described compound-material with removal lithium embedded characteristic is selected from LiCoO ₂, LiMn ₂O ₄, LiNi _1/3Mn _1/3Co _1/3O ₂, LiNi _1/2Mn _1/2O ₂, LiFePO ₄In a kind of; Described porous carbon material is meant one or more in active carbon, mesopore charcoal, carbon nanotube, charcoal fiber, the charcoal-aero gel.

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