RU2592863C1 - Supercapacitor with inorganic solid electrolyte and carbon electrodes - Google Patents

Abstract

FIELD: electronics.

SUBSTANCE: invention relates to solid-state micro-and nanoelectronics, namely, to supercapacitors with inorganic solid electrolyte, which can be used in various mobile communication devices, hybrid devices, such as power supply, due to accumulated therein electric charge. Supercapacitor with inorganic solid electrolyte comprises two identical electrodes separated with solid electrolyte, electrodes are manufactured from a mixture of solid electrolyte and carbon material, solid electrolyte is made of solid solution RbNO₃ and RbNO₂, taken in molar ratio of 7:3, electrode material consists of a mixture of amorphous carbon and Graphene, and current leads are manufactured of aluminium powder, laminated to the surface of the supercapacitor.

EFFECT: improving performance characteristics of super- capacitor, including specific capacitance of 40-100 s/g, calculated on the weight of carbon material contained in the electrode and operating in temperature range T_op= 150-180 °C, is the technical result of invention.

1 cl, 1 dwg

Description

The invention relates to the field of solid-state micro- and nanoelectronics, namely to supercapacitors with inorganic solid electrolyte, which can be used in various mobile communication devices, hybrid devices, such as a power source, due to the electric charge accumulated in them.

Solid-state supercapacitors are known that use proton-conducting polymer electrolytes (1. Keryn Lian, Qifeng Tian Electrochemistry Communications 12 (2010) 517-519 Solid asymmetric electrochemical capacitors using proton-conducting polymer electrolytes; Han Gao, Keryn Lian, High rate all- solid electrochemical capacitors using proton conducting polymer electrolytes Journal of Power Sources 196 (2011) 8855-8857). In these supercapacitors, various organic compounds are used, polymer membranes are impregnated with acids, which is their drawback, since corrosion-resistant materials must be used for the manufacture of such devices, and recycling problems arise with their disposal.

The electrolytes currently used for the manufacture of supercapacitors are susceptible to decomposition with possible fire during thermal exposure, which makes them unstable to high temperatures.

Due to the use of organic polymer membranes impregnated with acids having a low voltage value of electrochemical decomposition, the resulting supercapacitors can only work at low operating voltages, less than 1 V, which can also be attributed to their disadvantages.

In the course of our studies (2. AA Iskakova, NF Uvarov "Solid electrolytes in the binary system RbNO ₃ -RbNO ₂ " Solid State Ionics 188 (2011) 83-85), it was shown that solid solutions based on rubidium nitrate have high ionic conductivity and can be used as solid electrolytes for various electrochemical devices. For example, a solid solution of rubidium nitrate and nitrite, taken in a molar ratio of 7: 3, has an ionic conductivity of about 10 ^-4 S / cm at T = 160 ° C and a high value of the electrochemical decomposition potential (above 3 V), which allows the use of this solid electrolyte in solid-state supercapacitors operating at voltages above 1 V.

The closest analogue of the invention adopted for the prototype is a supercapacitor with an inorganic composite solid electrolyte, including electrodes separated by a highly conductive solid electrolyte, the positive and negative electrodes are made of a composite containing nanoscale oxide LiMn _2-x Me _x O ₄ , where Me = Ni ^{2 +} , Mn ³⁺ , composite solid electrolyte and electrically conductive soot, solid electrolyte is made of composite solid electrolyte based on lithium perchlorate 0.4LiClO ₄ -0.6Al ₂ O ₃ , and the current supply consists of two plates of metallic nickel mounted on the outer sides of the electrodes (3. Pat. RU No. 2522947, Application No. 2012149307/07, Publish. July 20, 2014). The disadvantage of this supercapacitor is the relatively low values of specific electric capacitance from 3 to 25 F / g, calculated on the total mass of transition metal oxide contained in the electrode material in the case of symmetric cells and on the mass of transition metal oxide contained in the cathode material for asymmetric cells and operating at relatively high temperatures T _slave = 250 ° C.

The problem to be solved by the claimed technical solution is the development of a supercapacitor with an inorganic solid electrolyte having large values of specific electric capacity at lower temperatures.

The problem is solved due to the fact that in the inventive supercapacitor, including current leads, two electrodes separated by a solid electrolyte, a solid electrolyte placed between the electrodes is made of a solid solution of RbNO ₃ and RbNO ₂ with a molar ratio of components equal to 7: 3, the electrodes are made of a mixture solid electrolyte of the above composition and carbon electrode material, taken in the ratio: solid electrolyte 70-90 weight. %, carbon electrode material - the rest, while the carbon electrode material consists of a mixture of amorphous carbon and graphene, taken in the ratio: amorphous carbon 50-80 weight. %, graphene - the rest, and current leads are made of extruded aluminum powder.

The salient features of the claimed technical solution are:

- electrodes are made of a mixture of solid electrolyte and carbon material, taken in the ratio: solid electrolyte 70-90 weight. %, carbon material - the rest;

- solid electrolyte is made from a solid solution of RbNO ₃ and RbNO ₂ taken in a molar ratio of 7: 3;

- carbon material consists of a mixture of amorphous carbon and graphene, taken in the ratio: amorphous carbon 50-80 weight. %, graphene - the rest;

- current leads are made of aluminum powder pressed to the surface of the supercapacitor.

As a result of a subject study of publicly available information and a comparison of the particular features of the invention with the features of the closest analogue, it was found that the inventive supercapacitor meets the criterion of "novelty", since the prior art has not found an analogue with an identical set of all the essential features claimed by the claims.

Solid electrolyte composition 0.7RbNO ₃ -0.3RbNO ₂ and carbon material, taken in weight ratios: solid electrolyte 70-90 weight. %, carbon material - the rest is thoroughly mixed and heated at 180 ° C for 30 minutes in vacuum. The carbon material is obtained by mixing amorphous carbon and graphene, taken in the ratio: amorphous carbon 50-80 weight. %, graphene - the rest, in ethanol with simultaneous exposure to ultrasound for 10 minutes Solid electrolyte 0.7RbNO ₃ -0.3RbNO ₂ is prepared by fusion of the starting components at 400 ° C. As a material for the manufacture of current leads using aluminum powder.

From the obtained electrode composite, solid electrolyte and aluminum powder, a symmetric solid-state electrochemical cell is formed, consisting of five layers of Al / 0.7RbNO ₃ -0.3RbNO ₂ + C / 0.7RbNO ₃ -0.3RbNO ₂ /0.7RbNO ₃ -0.3RbNO ₂ + C / Al with a thickness of each layer of not more than 100 microns. A schematic representation of a supercapacitor is shown in FIG. 1. The electrodes 1 are made of a mixture of a solid solution of 0.7RbNO ₃ -0.3RbNO ₂ and carbon material. Between the electrodes 1 is a solid electrolyte 2 made of a solid solution of the composition 0.7RbNO ₃ -0.3RbNO ₂ . Two layers of pressed aluminum powder, fixed on the outer faces of the electrodes, serve in this supercapacitor as current leads 3. According to the claimed invention, the supercapacitor is manufactured by pressing.

Measurement of electrochemical properties is carried out in vacuum. The specific capacitance value is calculated using the cyclic voltammetry method in the voltage range from -3 to 3 V. The obtained specific capacitance values per gram of carbon material are 45 F / g at a temperature of 100 F / g at a temperature of 150 and 180 ° C, respectively . As the temperature decreases below 150 ° C, the capacitance decreases due to the high resistance of the electrolyte; at temperatures above 190 ° C, the characteristics of the supercapacitor become unstable due to the phase transition occurring in the solid solution. With an increase in the content of amorphous carbon above 80 weight. % capacitance decreases due to the high resistance of the electrode; when the content of amorphous carbon is below 50%, the capacitance decreases due to aggregation of graphene into dense layers with a low specific surface.

The claimed supercapacitor differs from other prior art in that it is used as solid electrolyte inorganic electrolyte on the basis of rubidium nitrate 0.7RbNO ₃ -0.3RbNO ₂ with a high electrochemical decomposition potential (U _dec.> 3 V) and a higher specific capacitance values. It does not contain organic compounds, so it is resistant to thermal effects (operating temperature range T _work = 150-180 ° C).

The technical result of the claimed technical solution is the development of a symmetric supercapacitor with an inorganic solid rubidium-conducting electrolyte that provides high performance, namely: thermal stability in the temperature range 150-180 ° C, high potential of operating voltage U _slave > 3V and high capacity of 100 F / g, calculated on the mass of active carbon material, at 180 ° C.

Claims (1)

A supercapacitor with an inorganic solid electrolyte and carbon electrodes, including current leads, two electrodes separated by a solid electrolyte, and characterized in that the solid electrolyte placed between the electrodes is made of a solid solution of RbNO ₃ and RbNO ₂ with a molar ratio of components equal to 7: 3, the electrodes are made of a mixture of a solid electrolyte of the above composition and carbon electrode material, taken in the ratio: solid electrolyte 70-90 weight. %, carbon electrode material - the rest, while the carbon electrode material consists of a mixture of amorphous carbon and graphene, taken in the ratio: amorphous carbon 50-80 weight. %, graphene - the rest, and current leads are made of extruded aluminum powder.

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