A kind of high energy density supercapacitor and preparation method thereof

Abstract

The invention discloses a high-energy-density super capacitor and a preparation method thereof, and belongs to the field of electrochemical energy storage. Through introducing a metal lithium electrode in the assembling process of the super capacitor, the electrochemical state of an electrode material is controlled, charges are injected into the electrode material, positive and negative materials for electrochemical potential adjustment are obtained, working potential windows of positive and negative electrodes in the super capacitor are optimized, the working voltage and the specific capacity of the device are simultaneously improved, and the energy density of the super capacitor is improved. At the same time, the obtained capacitor can carry out electrochemical activation process through the metal lithium electrode to stabilize the potential windows so as to enable the super capacitor to have super long cycle life. The super capacitor and the method provided by the invention are simple in technical process, are compatible with a conventional process, and substantially improve the device performance, thereby having quite large application prospect.

Description

technical field

[0001] The invention relates to the technical field of supercapacitors for electrochemical energy storage, in particular to a high energy density supercapacitor and a preparation method thereof. Background technique

[0002] Supercapacitors, also known as electrochemical capacitors, rely on the adsorption of double-layer ions on the electrode surface or redox reactions to store charges, and their performance is between that of physical capacitors and secondary batteries. Supercapacitors not only have an energy density much higher than that of physical capacitors, they can charge and discharge within seconds, can charge and discharge with high power / current, have a cycle life of tens of thousands of times, and have a charge and discharge efficiency close to 100%. It can be used in the environment (-40 ~ 70 ℃) and has high safety and long-term maintenance-free characteristics, which are incomparable to secondary batteries. These superior properties make superc...

Examples

Embodiment 1

[0038] Regulate graphene as electrode material (oxygen content 6.5at%, specific surface area 412m 2 / g) and with LiPF 6 The ethylene carbonate / dimethyl carbonate solution is the process of the supercapacitor system of the electrolyte as follows:

[0039] Graphene materials are used to make electrode sheets, and LiPF 6 Ethylene carbonate / dimethyl carbonate solution as electrolyte (where LiPF 6 The concentration is 1mol / L, the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1), and it is used as positive and negative electrodes and lithium foil electrodes to assemble supercapacitor devices. The upper limit of the available potential window of the electrolyte is between 4.3V and 0.001V vs. Li, so that the positive and negative electrodes are charged and discharged at a constant current of 175mA / g with respect to the lithium electrode for 20 cycles respectively. Obtain the intersection point E'ov of the positive electrode discharge curve and the negative electrode...

Embodiment 2

[0044] Multi-walled carbon nanotubes (diameter2 / g, oxygen content 4.5at%) made into electrode sheet, with LiPF 6 Ethylene carbonate / dimethyl carbonate solution as electrolyte (where LiPF 6 The concentration is 1mol / L, the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1), and it is used as positive and negative electrodes and lithium foil electrodes to assemble supercapacitor devices. The upper limit of the available potential window of the electrolyte is between 4.3V and 0.001V vs. Li, so that the positive and negative electrodes are charged and discharged at a constant current of 175mA / g with respect to the lithium electrode for 20 cycles respectively. Obtain the intersection point E'ov of the positive electrode discharge curve and the negative electrode charge curve. Then charge (discharge) the positive and negative electrodes to E’ov constant voltage for 12 hours at the same time. A modulated supercapacitor device is obtained.

[0045] Such as Image 6 ...

Embodiment 3

[0048] Single-walled carbon nanotubes (diameter2 / g, oxygen content 6.5at%) made into electrode sheet, with LiPF 6 Ethylene carbonate / dimethyl carbonate solution as electrolyte (where LiPF 6 The concentration is 1mol / L, the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1), and it is used as positive and negative electrodes and lithium foil electrodes to assemble supercapacitor devices. The upper limit of the available potential window of the electrolyte is between 4.3V and 0.001V vs. Li, so that the positive and negative electrodes are charged and discharged at a constant current of 175mA / g with respect to the lithium electrode for 20 cycles respectively. Obtain the intersection point E'ov of the positive electrode discharge curve and the negative electrode charge curve. Then charge (discharge) the positive and negative electrodes to E’ov constant voltage for 12 hours at the same time. A modulated supercapacitor device is obtained.

[0049] Such as Figure ...

technical field

[0001] The invention relates to the technical field of supercapacitors for electrochemical energy storage, in particular to a high energy density supercapacitor and a preparation method thereof. Background technique

[0002] Supercapacitors, also known as electrochemical capacitors, rely on the adsorption of double-layer ions on the electrode surface or redox reactions to store charges, and their performance is between that of physical capacitors and secondary batteries. Supercapacitors not only have an energy density much higher than that of physical capacitors, they can charge and discharge within seconds, can charge and discharge with high power / current, have a cycle life of tens of thousands of times, and have a charge and discharge efficiency close to 100%. It can be used in the environment (-40 ~ 70 ℃) and has high safety and long-term maintenance-free characteristics, which are incomparable to secondary batteries. These superior properties make superc...

Examples

Embodiment 1

[0038] Regulate graphene as electrode material (oxygen content 6.5at%, specific surface area 412m 2 / g) and with LiPF 6 The ethylene carbonate / dimethyl carbonate solution is the process of the supercapacitor system of the electrolyte as follows:

[0039] Graphene materials are used to make electrode sheets, and LiPF 6 Ethylene carbonate / dimethyl carbonate solution as electrolyte (where LiPF 6 The concentration is 1mol / L, the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1), and it is used as positive and negative electrodes and lithium foil electrodes to assemble supercapacitor devices. The upper limit of the available potential window of the electrolyte is between 4.3V and 0.001V vs. Li, so that the positive and negative electrodes are charged and discharged at a constant current of 175mA / g with respect to the lithium electrode for 20 cycles respectively. Obtain the intersection point E'ov of the positive electrode discharge curve and the negative electrode...

Embodiment 2

[0044] Multi-walled carbon nanotubes (diameter2 / g, oxygen content 4.5at%) made into electrode sheet, with LiPF 6 Ethylene carbonate / dimethyl carbonate solution as electrolyte (where LiPF 6 The concentration is 1mol / L, the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1), and it is used as positive and negative electrodes and lithium foil electrodes to assemble supercapacitor devices. The upper limit of the available potential window of the electrolyte is between 4.3V and 0.001V vs. Li, so that the positive and negative electrodes are charged and discharged at a constant current of 175mA / g with respect to the lithium electrode for 20 cycles respectively. Obtain the intersection point E'ov of the positive electrode discharge curve and the negative electrode charge curve. Then charge (discharge) the positive and negative electrodes to E’ov constant voltage for 12 hours at the same time. A modulated supercapacitor device is obtained.

[0045] Such as Image 6 ...

Embodiment 3

[0048] Single-walled carbon nanotubes (diameter2 / g, oxygen content 6.5at%) made into electrode sheet, with LiPF 6 Ethylene carbonate / dimethyl carbonate solution as electrolyte (where LiPF 6 The concentration is 1mol / L, the volume ratio of ethylene carbonate to dimethyl carbonate is 1:1), and it is used as positive and negative electrodes and lithium foil electrodes to assemble supercapacitor devices. The upper limit of the available potential window of the electrolyte is between 4.3V and 0.001V vs. Li, so that the positive and negative electrodes are charged and discharged at a constant current of 175mA / g with respect to the lithium electrode for 20 cycles respectively. Obtain the intersection point E'ov of the positive electrode discharge curve and the negative electrode charge curve. Then charge (discharge) the positive and negative electrodes to E’ov constant voltage for 12 hours at the same time. A modulated supercapacitor device is obtained.

[0049] Such as Figure ...

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