CN1404082A

CN1404082A - Treatment process of active carbon for super capacitor

Info

Publication number: CN1404082A
Application number: CN02112894A
Authority: CN
Inventors: 唐民洪; 褚德威; 阎智刚; 祝士平
Original assignee: LONGYUAN SHUANGDENG POWER SUPPLY CO Ltd JIANGSU
Current assignee: LONGYUAN SHUANGDENG POWER SUPPLY CO Ltd JIANGSU
Priority date: 2002-04-18
Filing date: 2002-04-18
Publication date: 2003-03-19
Anticipated expiration: 2022-04-18
Also published as: CN1266721C

Abstract

The treatment process of active carbon for super capacitor features the undervoltage deposition of one of the metal ion of Al3+, Li+, Zn2+, Cu2+, Ti+ and Pb2+ on the surface of active carbon to form quasi-Faraday capacitor for electrochemical double layer capacitor. Any one kind of the solution of the said ions may be added into super capaictor KOH electrolyte solution or any one kind of the solution of the said ions may be used in modifying active carbon powder to deposit the ion in the pores. The super capacitor of the present invention is matched with accumulator or other battery to constitute composite battery with high power, great capacitance and fast charging. The composite battery may be used widely in astronautic, millitary, traffic, electric power, communication and other fields.

Description

Treatment method of activated carbon for super capacitor

Technical Field

The invention relates to a method for treating activated carbon used by a super capacitor, belonging to the technical field of super capacitor manufacturing.

Background

The demands of future war on competition and space weapons in the space field, such as laser weapons used for destroying or blinding enemy reconnaissance, communication satellite and the like, need energy sources with high power density for support. The starting and reliable launching power support of strategic weapon carrier vehicles in alpine regions require reliable high power output and energy storage power supply devices with excellent temperature characteristics. The enhancement of the environmental consciousness of people enables the electric automobile or the low-pollution hybrid electric automobile to be used as a clean vehicle to approach the life of people; the requirement for high-power of the electric vehicle in the starting and accelerating processes is improved. The existing battery is difficult to meet the requirements of high power, large capacity and quick charging. The electrochemical super capacitor is matched with a storage battery or other batteries to form the composite battery, so that the requirements on relevant indexes of the storage battery can be reduced, and the energy-saving effect is achieved. Computers have been applied to various fields of human society as a modern high-technology symbol, and supercapacitors are very suitable as a backup power source for computer systems with their excellent performance. Meanwhile, the super capacitor has excellent performance as an uninterruptible power supply of railway, electric power and communication systems. Carbon material based supercapacitors are of great practical interest for applications such as automotive, telecom, engine start, etc. due to their relatively low cost and superior performance.

In recent years, supercapacitors have become one of the most active research fields for materials, electronics, chemistry and physics multidisciplinary research in internationally developed countries (usa, russia, japan and european countries), and the goal thereof is to prepare electrode materials required for compact energy with high specific power and high specific capacity, electrolyte with wide electrochemical window and high conductivity, and further prepare large supercapacitors with ultra-high power and ultra-high capacity for power applications. The active carbon is used as the active substance of the super capacitor, the specific capacity is lower, the pure active carbon is difficult to meet the use requirement of the super capacitor in many fields as the active substance of the super capacitor, and the improvement of the specific capacity of the super capacitor becomes urgent.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provides a method for treating the activated carbon for the super capacitor, which can effectively improve the specific capacity of the super capacitor.

The technical scheme of the invention is as follows: the method for treating the active carbon for the super capacitor is to treat metal ions Al³⁺、Li⁺、Zn²⁺、Cu²⁺、Tl⁺、Pb²⁺Any one of the above is subjected to underpotential deposition on the surface of the activated carbon, so that the faradaic pseudo-capacitance is provided for the electrochemical double-layer capacitor.

The method can add the concentration of 1.0-3.0 multiplied by 10 into the KOH electrolyte of the super capacitor^-2mol/LAl³⁺、1.0～4.0×10^-2mol/L Li⁺、1.0～3.0×10^-2mol/L Zn²⁺、0.5～2.0×10^-2mol/LCu²⁺、1.0～3.0×10^-2mol/L Tl⁺、1.0～2.0×10^-2mol/L Pb²⁺Any one of the ionic solutions of (1). Al may also be used³⁺、Li⁺、Zn²⁺、Cu²⁺、Tl⁺、Pb²⁺Any one of the above modifies the activated carbon powder so that the ions are deposited in the micropores of the activated carbon.

In which Pb is used²⁺The method for modifying the active carbon powder is to use Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the activated carbon, the free solution is filtered out, then the NaOH solution is added, and the stirring is carried out, so that Pb (OH) is deposited on the surface of the activated carbon₂And carrying out suction filtration to obtain 5-30% Pb (OH) deposit₂The active substance of (1). Or with Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the active carbon, free solution is filtered out, and then H is added₂SO₄Stirring the solution to deposit PbSO on the surface of the activated carbon₄And leaching to obtain 10-30% PbSO₄The active substance of (1). Or with Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the active carbon, free solution is filtered out, and then H is added₃PO₄Stirring the solution to deposit Pb on the surface of the activated carbon₃(PO₄)₂And carrying out suction filtration to obtain 5-30% deposited Pb₃(PO₄)₂The active substance of (1).

The technology for improving the capacitance of the double-layer capacitor by utilizing the Faraday quasi-capacitance is very significant, and the invention searches for metal ions capable of generating under-potential deposition on the surface of an activated carbon material so as to improve the specific capacitance of an activated carbon electrode and further increase the capacity of a super capacitor. Monolithic double layer capacitors are based on the double layer capacitance at the solid/liquid interface of high specific surface area materials, such as activated carbon. Similar to conventional capacitors, storage of electrical energy is based on charging within an electrolyte bilayer across the electrode/solution interface. When a direct voltage is applied to the interface of the electrodes, an electrical double layer builds up to store electrical energy. The electrical energy stored in the bilayer is proportional to the surface area of the electrode and inversely proportional to the thickness of the bilayer. Electrochemical Double Layer Capacitors (EDLCs) are devices comprising a pair of ideally polarized electrodes; in other words, only those devices that do not undergo faradaic reactions in the operating potential range can be considered EDLCs, and all accumulated charge is used to form the conductor/solution bilayer. The so-called super capacitor includes, besides the electric double layer electric energy storage, the two-dimensional and quasi two-dimensional faradaic reaction on the electrode interface, which makes the electric energy converted into chemical energy to be stored on the interface. The metal ions can be reduced to metal on the electrode when the electrode potential is lower than the reversible equilibrium electrode potential, and some metal ions can be deposited on a substrate of dissimilar metal when the electrode potential is positive than the reversible equilibrium electrode potential to form a metal monoatomic layer, namely, so-called underpotential deposition. This process differs from the typical deposition process in that a monolayer of metal atoms is formed. Due to the thermodynamic reasons of the electrode/electrolyte interface, underpotential deposition, such as monolayer deposition of H or Pb on rare metals, can occur before the three-dimensional deposition of new phases, so that the surface of the electrode is partially covered; this forms an electro-absorption quasi-capacitor.

The metal ions which are subjected to the underpotential deposition on the surface of the activated carbon material theoretically can be subjected to the underpotential deposition on the surface of an activated carbon electrode respectively, and the metal ions which are subjected to the underpotential deposition on the surface of the activated carbon electrode of the super capacitor are found, and the addition of the metal ions into the super capacitor contributes to the capacity increase. Taking Pb as an example，Pb²⁺In the capacitor system, Pb (OH)₂、Pb₃(PO₄)₂Or PbSO₄The form is deposited on the surface of the negative electrode activated carbon, and the negative electrode undergoes the following electrochemical reaction when the capacitor is charged and discharged. Providing faraday pseudocapacitance for capacitor operation.

Negative electrode:

to prevent Pb (OH)₂Or Pb₃(PO₄)₂Pb dissolved in alkaline electrolyte²⁺Lead crystal branches are generated to generate a short circuit phenomenon, SO is added into an electrolyte system₄ ^2-。

Detailed Description

The first embodiment is as follows: adding 2.0 x 10 of KOH electrolyte into a super capacitor^-2mol/L Al³⁺Al (OH)₃Containing 3.0X 10^-2mol/L Li⁺Of LiOH, containing 2.0X 10^-2mol/L Zn²⁺ZnO of (1.0X 10)^-2mol/LCu²⁺Cuso of (2.0X 10)^-2mol/L Tl⁺TlNo of₃Containing 1.5X 10^-2mol/L Pb²⁺Pb (Ac)₂In the above case, the metal ions are deposited on the surface of the activated carbon in the form of alkali by the supercapacitor charge-discharge activation process.

Example two: with Al³⁺、Li⁺、Zn²⁺、Cu²⁺、Tl⁺、Pb²⁺Any one of the active substances, namely the activated carbon powder, is modified by a certain method, so that the ions are deposited in micropores of the activated carbon.

Here with Pb²⁺The method of processing is illustrated for example:

(1) with 0.7mol/L Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the active carbon, free solution is filtered out, 7mol/L NaOH solution is added, and the mixture is stirred to ensure thatDepositing Pb (OH) on the surface of the obtained activated carbon₂Suction filtration to obtain the deposit Pb (OH)₂The active material of (1), Pb (OH) in the finally obtained active material₂11% of the total weight of the material, and a supercapacitor made therefrom, 11% of Pb (OH) is deposited₂When the specific capacity is increased by 30.5F/g.

(2) With 0.7mol/L Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the active carbon, the free solution is filtered out, and then 1.0mol/L H is added₂SO₄Stirring the solution to deposit PbSO on the surface of the activated carbon₄And carrying out suction filtration to obtain the deposited PbSO₄Active substance of (2), PbSO in the finally obtained active substance₄Accounting for 12 percent, thereby manufacturing the super capacitor.

(3) With 0.7mol/L Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the active carbon, the free solution is filtered out, and then 1.0mol/L H is added₃PO₄Stirring the solution to deposit Pb on the surface of the activated carbon₃(PO₄)₂Suction filtering to obtain deposited Pb₃(PO₄)₂Active material of (2), Pb in the finally obtained active material₃(PO₄)₂Accounting for 10 percent, thereby manufacturing the super capacitor.

Claims

1. A process for treating the activated carbon used for super capacitor features that the metal ions Al³⁺、Li⁺、Zn²⁺、Cu²⁺、Tl⁺、Pb²⁺Any one of the above is subjected to underpotential deposition on the surface of the activated carbon, so that the faradaic pseudo-capacitance is provided for the electrochemical double-layer capacitor.

2. The method of claim 1, wherein the concentration of KOH in the supercapacitor is 1.0 to 3.0X 10^-2mol/L Al³⁺、1.0～4.0×10^-2mol/L Li⁺、1.0～3.0×10^-2ol/L Zn²⁺、0.5～2.0×10^-2mol/L Cu²⁺、1.0～3.0×10^-2mol/L Tl⁺、1.0～2.0×10^-2mol/L Pb²⁺Any one of the ionic solutions of (1).

3. The method of claim 1, wherein Al is used³⁺、Li⁺、Zn²⁺、Cu²⁺、Tl⁺、Pb²⁺Any one of the above modifies the activated carbon powder so that the ions are deposited in the micropores of the activated carbon.

4. A method for treating activated carbon as claimed in claim 3, characterized in that Pb is used²⁺The method for modifying the active carbon powder is to use Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the activated carbon, the free solution is filtered out, then the NaOH solution is added, and the stirring is carried out, so that Pb (OH) is deposited on the surface of the activated carbon₂And carrying out suction filtration to obtain 5-30% Pb (OH) deposit₂The active substance of (1).

5. A method for treating activated carbon as claimed in claim 3, characterized in that Pb is used²⁺The method for modifying the active carbon powder is to use Pb (NO)₃)₂The solution is soaked in the activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the active carbon, free solution is filtered out, and then H is added₂SO₄Stirring the solution to deposit PbSO on the surface of the activated carbon₄And leaching to obtain 10-30% PbSO₄The active substance of (1).

6. A method for treating activated carbon as claimed in claim 3, characterized in that Pb is used²⁺The method for modifying the active carbon powder is to use Pb (NO)₃)₂The solution is soaked inthe activated carbon under vacuum condition to lead Pb (NO)₃)₂The solution completely enters the micropores of the active carbon, free solution is filtered out, and then H is added₃PO₄Stirring the solution to deposit Pb on the surface of the activated carbon₃(PO₄)₂And carrying out suction filtration to obtain 5-30% deposited Pb₃(PO₄)₂The active substance of (1).