Hybrid Supercapacitor

Abstract

A supercapacitor has a cathode and an anode. At least one of the cathode and the anode of the supercapacitor contains at least one material which stores polyvalent cations. Additionally, the supercapacitor also has an electrolyte. The electrolyte contains an electrolyte salt, and the electrolyte salt has at least one polyvalent cation.

Claims

1. A hybrid supercapacitor comprising: a cathode; an anode; and an electrolyte, wherein: at least one of the cathode and the anode contains at least one material which stores polyvalent cations, and the electrolyte contains an electrolyte salt having at least one polyvalent cation.

2. The hybrid supercapacitor according to claim 1, wherein the at least one polyvalent cation is selected from the group consisting of Ca.sup.2+, Mg.sup.2+, Ba.sup.2+, Sr.sup.2+, Zn.sup.2+, Cu.sup.2+, Fe.sup.2+, Mn.sup.2+, Ni.sup.2+, Co.sup.2+, Al.sup.3+, V.sup.3+, Y.sup.3+ and mixtures thereof.

3. The hybrid supercapacitor according to claim 1, wherein the electrolyte salt contains at least one anion selected from the group consisting of (CF.sub.3SO.sub.2).sub.2N.sup.−, ClO.sub.4.sup.−, BF.sub.4.sup.−, and PF.sub.6.sup.−.

4. The hybrid supercapacitor according to claim 1, wherein the electrolyte contains a solvent selected from the group consisting of acetonitrile, propylene carbonate, at least one ionic liquid, water and mixtures thereof.

5. The hybrid supercapacitor according to claim 1, wherein the at least one material of the cathode which stores polyvalent cations is selected from the group consisting of NiHCF, CuHCF, K.sub.2BaFe(CN).sub.6, VO.sub.2, V.sub.2O.sub.5, Mn.sub.xCo.sub.yO.sub.4 and mixtures thereof, where 2.50<x+y<2.62.

6. The hybrid supercapacitor according to claim 1, wherein the at least one material of the anode which stores polyvalent cations contains β-SnSb.

7. The hybrid supercapacitor according to claim 1, wherein the at least one material of the at least one of the cathode and the anode which stores polyvalent cations is a pseudocapacitive material selected from the group consisting of MnO.sub.2, polymeric materials and mixtures thereof.

8. The hybrid supercapacitor according to claim 1, wherein the at least one of the cathode and the anode additionally contains a capacitive material selected from among carbon nanotubes, carbon nanofibers, graphene, functionalized graphene, activated carbon and mixtures thereof.

9. The hybrid supercapacitor according to claim 1, wherein the at least one of the cathode and the anode contains graphite and/or nanoparticles of carbon.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] A working example of the disclosure is shown in the FIGURE and is described in more detail in the following description.

[0017] The FIGURE schematically shows the structure of a supercapacitor according to a working example of the disclosure, which is configured as symmetric hybrid supercapacitor.

DETAILED DESCRIPTION

[0018] A supercapacitor 1 according to a working example of the disclosure is configured as symmetric hybrid supercapacitor. It has the structure depicted in the figure. A cathode 2 has been applied to a first collector 3. An anode 4 has been applied to a second collector 5. An electrolyte 6 has been introduced between the cathode 2 and the anode 4. A separator 7 separates the cathode 2 from the anode 4. Embedding of Mg.sup.2+ ions into the cathode 2 and into the anode 4 is shown schematically as an example of polyvalent cations in the figure. Here, the figure shows activated carbon as capacitive electrode material on the surface of which, during charging, negative charge carriers of the electrolyte 6 accumulate at the cathode 2 and on the surface of which positive charge carriers of the electrolyte 6 accumulate at the anode 4. Furthermore, four enlargements show how the magnesium ion cathode material of the cathode 2, in the present case Mn.sub.2.15Co.sub.0.37O.sub.4, deintercalates Mg.sup.2+ ions and the magnesium ion anode material of the anode 4, in the present case β-SnSb, stores Mg.sup.2+ ions by alloying.

[0019] To produce the cathode 2, a mixture of 66.83 g of activated carbon, 15.67 g of Mn.sub.2.15Co.sub.0.37O.sub.4 particles coated with carbon nanoparticles, 5 g of graphite particles and 5 g of carbon nanoparticles is firstly produced. This is drymixed at 1000 rpm in a mixer for 10 minutes. 90 ml of isopropanol are then added and the suspension obtained is firstly stirred at 2500 rpm for 2 minutes, then treated with ultrasound for 5 minutes and subsequently stirred at 2500 rpm again for 4 minutes. 7.5 g of polytetrafluoroethylene (PTFE) are subsequently added as binder to the suspension and the mixture is again stirred at 800 rpm for 5 minutes until the suspension takes on a paste-like consistency. The paste is rolled out on a glass plate to give a 150 μm thick cathode 2 which is then applied to the first collector 3.

[0020] To produce the anode 4, a mixture of 66.83 g of activated carbon, 15.67 g of β-SnSb particles coated with carbon nanoparticles, 5 g of graphite particles and 5 g of carbon nanoparticles is firstly produced. This is drymixed at 1000 rpm in the mixer for 10 minutes. 90 ml of isopropanol are then added and the suspension obtained is firstly stirred at 2500 rpm for 2 minutes, then treated with ultrasound for 5 minutes and subsequently stirred at 2500 rpm again for 4 minutes. 7.5 g of polytetrafluoroethylene are subsequently added as binder to the suspension and the mixture is stirred again at 800 rpm for 5 minutes until the suspension takes on a paste-like consistency. The paste is rolled out on a glass plate to give a 150 μm thick anode 4 which is then applied to the second collector 5.

[0021] A 1 M solution of Mg(TFSI).sub.2 in a solvent mixture of 83% by volume of acetonitrile and 17% by volume of water is used as electrolyte 6. The separator 7 consists of a woven polyamide/polyethylene terephthalate/cellulose fabric having a porosity of 62%.

[0022] The supercapacitor has a high energy density and a high power density.