Alkali metal ion capacitor taking lithium orthovanadate as negative electrode active material

A technology of negative electrode active material and positive electrode active material, applied in the field of electrochemistry, can solve the problems of low energy density of alkali metal ion capacitors, and achieve the effects of excellent cycle performance, good rate performance and high energy density

Inactive Publication Date: 2016-07-06
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The object of the present invention is to provide a kind of alkali metal ion capacitor with lithium orthovanadate as the negative electrode active material, to overcome the low problem of energy density of the alkali metal ion capacitor reported before

Method used

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  • Alkali metal ion capacitor taking lithium orthovanadate as negative electrode active material
  • Alkali metal ion capacitor taking lithium orthovanadate as negative electrode active material
  • Alkali metal ion capacitor taking lithium orthovanadate as negative electrode active material

Examples

Experimental program
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Effect test

Embodiment 1

[0042] Mix vanadium pentoxide and lithium carbonate according to the V:Li molar ratio of 1:3, grind for 10 minutes, and calcinate the obtained powder at 600°C for 5 hours, then at 900°C for 3 hours, and cool in the furnace Lithium orthovanadate (Li 3 VO 4 )sample. Accurately weigh lithium orthovanadate, acetylene black and polyvinylidene fluoride (PVDF) according to the mass fraction of 80%: 10%: 10%, use 1-methyl-2-pyrrolidone as a solvent, and uniformly mix to form a slurry, Spread evenly on copper foil. The coated electrode sheet was vacuum-dried at 120°C for more than 12 hours, and an electrode with a diameter of 19 mm was punched out with a punching machine. With this electrode as the negative pole, the activated carbon electrode prepared in Comparative Example 1 as the positive pole, the porous polypropylene with a porosity of 40% as the diaphragm, 1MLiPF 6 A mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (DEC) (mass ratio 1:1:1)...

Embodiment 2

[0044] Lithium orthovanadate (Li 3 VO 4 ) was prepared the same as in Example 1, and then passed through high-speed ball milling with carbon nanofibers (CNF) to obtain Li 3 VO 4 -CNF compound, according to the method of Example 1 to prepare the negative electrode. Using graphene with an average thickness of 10 layers of graphite sheets as the positive electrode active material, a positive electrode was prepared according to the method of Comparative Example 1. Then change the diaphragm into P(VDF-HFP) with a porosity of 45%, and other conditions are the same as in Example 1 to form an asymmetric lithium ion capacitor, and carry out corresponding electrochemical performance (the voltage range is 0-3.8 V) and safety performance test (overcharged to 4.5V), the relevant test data are collected in Table 1. figure 2 , image 3 They are the charge-discharge curves and the relationship between energy density and power density at different current densities.

Embodiment 3

[0046] According to our disclosed method (journal NanoLetters, the 4715-4720 page of volume 13 in 2013), adopt hydrothermal method to obtain lithium orthovanadate (Li 3 VO 4 ) and graphene (G), and then prepared as a negative electrode according to the method of Example 2. Using graphene with an average thickness of 10 layers of graphite sheets as the positive electrode active material, a positive electrode was prepared according to the method of Comparative Example 1. Then, change the electrolyte to 1MNaPF 6 Outside the mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (DEC) (mass ratio 1:1:1), the diaphragm is the same as in Example 2 to form an asymmetric sodium ion capacitor , carry out the corresponding electrochemical performance (voltage range of 0-3.8V) and safety performance test (overcharge to 4.5V), and collect the relevant test data in Table 1.

[0047] The highest energy density and the highest power density situation (accordi...

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Abstract

The invention belongs to the electrochemical technical field, and specifically to an alkali metal ion capacitor taking lithium orthovanadate as a negative electrode active material. The negative electrode active material of the alkali metal ion capacitor adopts lithium orthovanadate or a modified object of lithium orthovanadate; the electrolyte adopts an organic electrolyte capable of conducting the alkali metal ions; and the positive electrode active material adopts a carbon material, or a dopant or a mixture of the carbon material capable of generating negative ion reversible adsorption / desorption in the organic electrolyte. The alkali metal ion capacitor has quite high energy density and power density.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and specifically relates to an alkali metal ion capacitor using lithium orthovanadate as a negative electrode active material, and also relates to the application of the hybrid capacitor. Background technique [0002] At present, the supercapacitor is mainly used as the backup power supply of the battery. When it is used in combination with the battery, it can meet the high power demand of the electric vehicle when starting, accelerating and climbing, and can quickly store the large current generated by the generator when the car brakes. , thus reducing the impact and performance degradation of the battery caused by high-current charging and discharging. Its power density is as high as 10kW / kg, and its cycle performance is excellent (several million cycles), but its energy density is low (less than 10Wh / kg); in addition, supercapacitors are also used in other occasions that require high ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01G11/50H01G11/30
CPCY02E60/13H01G11/50H01G11/30
Inventor 王法星朱玉松张翼吴宇平
Owner NANJING UNIV OF TECH
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