KR20220000212A - Supercapacitor comprising silicon oxy carbide lamellas and preparation method of the same - Google Patents

Abstract

Disclosed are a supercapacitor with improved energy density and power density, and a preparing method thereof. The present invention provides a preparing method of a supercapacitor, which comprises: a reaction step of reacting siloxene and alginate to obtain silicon oxycarbide; a slurry preparation step of preparing electrode material slurry by mixing the silicon oxycarbide, a conductive carbon material, and a binder; and a thin film layer preparing step of coating the electrode material slurry on a substrate and drying the same, to prepare a silicon oxycarbide thin film layer.

Description

Supercapacitor including silicon oxycarbide thin film layer and manufacturing method thereof

The present invention relates to a supercapacitor and a method for manufacturing the same, and more particularly, to a supercapacitor with improved power density and a method for manufacturing the same.

With the rapid growth of renewable energy sources (solar, wind and mechanical energy collecting devices), the demand for sustainable energy storage technology in daily life is increasing (Non-Patent Document 1).

Among the available energy storage devices, including lithium- and sodium-ion batteries (LIBs and SIBs, respectively), supercapacitors are attracting attention (rather than LIBs and SIBs) due to their high power density, medium energy density and long life cycle (non-patent literature). 2).

The development of new electrode materials with high capacitance, heat resistance, high conductivity, high surface area, and excellent electrochemical stability is an excellent way to improve the performance of supercapacitors (Non-Patent Documents 3 and 4), and Recent research is underway to improve the energy/power performance of electrochemical energy storage (EES) through the development of novel separators, to elucidate the role of different solvents and electrolytes, and to develop novel nanostructured materials for high-capacity electrodes. There is (Non-Patent Documents 5 to 7).

Accordingly, the present inventors have conducted research to further improve the energy density of the supercapacitor, and as a result, it has been found that the supercapacitor can exhibit excellent energy density and power density by including a silicon oxycarbide thin film layer, leading to the present invention. .

Patent Publication No. 10-2016-0016385 (2016.02.15.)

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The present invention has been devised to solve the problems of the prior art, and provides a supercapacitor with improved energy density and power density and a method for manufacturing the same.

In order to solve the above problems, the present invention provides a reaction step of reacting siloxene and alginate to obtain silicon oxycarbide; a slurry preparation step of preparing an electrode material slurry by mixing the silicon oxycarbide, a conductive carbon material, and a binder; and a thin film layer manufacturing step of coating the electrode material slurry on a substrate and drying the thin film layer to prepare a silicon oxycarbide thin film layer.

In addition, the siloxine (siloxene) provides a method for manufacturing a supercapacitor, characterized in that it is prepared by dissolving calcium by immersing a precursor containing calcium silicide in an acid.

In addition, the acid provides a method for manufacturing a supercapacitor, characterized in that the acid is a strong acid of 4 ℃ or less.

In addition, there is provided a method for manufacturing a supercapacitor, characterized in that the weight ratio of the siloxene to the alginate is 1:5 to 1:20.

In addition, the reaction step may include a grinding step of pulverizing siloxene and alginate into fine powder; an annealing step of heating the fine powder at a heating rate of 1 to 5°C and annealing at 180 to 220°C for 1 to 5 hours; and a heat treatment step of heating the annealed fine powder at a heating rate of 5 to 20° C. and heat treatment at 850 to 950° C. for 4 to 8 hours.

In addition, the heat treatment step provides a method of manufacturing a supercapacitor, characterized in that it is performed in an inert gas atmosphere.

In addition, the electrode material slurry provides a method for manufacturing a supercapacitor, characterized in that it contains 60 to 96% by weight of the silicon oxycarbide.

In addition, the silicon oxycarbide provides a method of manufacturing a supercapacitor, characterized in that the diffraction peak of 20 to 30 °.

Further, the silicon oxycarbide provides a supercapacitor production method characterized in that it has a peak in the FT-IR analysis, when 1390 to 1430cm ^-1 and 1600 to 1700cm ^-1.

In addition, the silicon oxycarbide provides a method for manufacturing a supercapacitor, characterized in that the Brunauer-Emmett-Teller (BET) surface area is 5.00 to 6.00 m ^{2 /g.}

In addition, the silicon oxycarbide provides a method for manufacturing a supercapacitor, characterized in that the O/Si atomic ratio is 1 to 1.5, and the C/Si atomic ratio is 1.5 to 2.5, as confirmed by XPS analysis.

In addition, the supercapacitor manufacturing method further includes a separator arrangement step and an electrolyte solution injection step after the electrode manufacturing step, wherein the electrolyte solution includes TEABF ₄ or Li ₂ SO _{4 It} provides a method for manufacturing a supercapacitor.

In order to solve the another problem, the present invention provides a supercapacitor comprising two or more electrodes containing an electrode material including silicon oxycarbide, a conductive carbon material and a binder, a separator positioned between the electrodes, and an electrolyte provides

In addition, the supercapacitor has ^{an energy density of 10 to 25mJ/cm 2} , and provides a supercapacitor, characterized in that it has a power density of 5,000 to 20,000W/kg.

The present invention can provide a supercapacitor capable of exhibiting excellent energy density and power density by including a silicon oxycarbide thin film layer in a supercapacitor and a method for manufacturing the same, and a method for manufacturing the same.

1 is a schematic diagram showing a method for preparing a silicon-oxy-carbide (silicon oxycarbide) thin film layer through a carbon-thermal reaction between a siloxene sheet and a sodium alginate biopolymer at 900°C;
2 is a TGA curve of siloxene, alginate and siloxene-alginate powder mixture;
3 is a TGA curve of a silicon oxycarbide thin film layer prepared by carbon heat;
4 is a view showing the physicochemical properties of the silicon oxycarbide thin film layer, (A) is an X-ray photoelectron spectroscopy (XPS) measurement spectrum of siloxene, alginate-derived carbon and silicon oxycarbide thin film layer, (B) ) is a comparative XPS spectrum of the Si(2p) state in siloxene and silicon oxycarbide, (C) is a comparative XPS spectrum of the O(1s) state present in siloxene, carbon and silicon oxycarbide, (D) is a comparative XPS spectrum of the C(1s) states present in carbon and silicon oxycarbide;
5 is a view showing the physicochemical properties of the silicon oxycarbide thin film layer, (A) is an X-ray diffraction diagram of silicon oxycarbide, (B) is alginate-derived carbon and Fourier-transform infrared spectroscopy of silicon oxycarbide ( FT-IR) spectrum, (C) is a Raman spectrum of the silicon oxycarbide thin film layer, (D) to (H) are high-resolution transmission electron micrographs of the silicon oxycarbide thin film layer obtained at various magnifications, (H) is a silicon oxycarbide thin film layer SAED patterns, (I) to (L) are elemental maps of silicon oxycarbide, (I) is an overlay image, (J) is an elemental map of Si atoms, (K) is an elemental map of O atoms, (L) is element map of C atom,
6 is a laser Raman spectrum of a siloxene sheet, alginate-derived carbon and silicon oxycarbide thin film layers;
7 is an N ₂ adsorption-desorption isotherm curve of silicon oxycarbide powder;
_{8 is a diagram showing the electrochemical analysis of a silicon oxycarbide electrode in 1M Li 2} SO ₄ using a three-electrode battery. In the cyclic voltage curve of the silicon oxycarbide electrode, (A) is an operation of -1.0 to 1.0 V; Cyclic voltage curve according to potential window, (B) is cyclic voltage curve according to operating potential window of -1.0 to 0.0 V, (C) is cyclic voltage curve according to operating potential window of 0.0 to 1.0 V, (D) is 100 Cyclic voltage curve according to scan rate of mVs ^-1 , (E) is a Nyquist plot of a silicon oxycarbide electrode, (F) is a charge-discharge (CD) profile of a silicon oxycarbide electrode,
9 is a _{diagram showing the electrochemical analysis of a silicon oxycarbide symmetric supercapacitor (symmetric supercapacitor) using 1M Li 2} SO ₄ and 1M TEABF ₄ electrolyte. At different operating voltages of 0.0 to 2.0 V, (A) is 100 mV s _{Cyclic voltage curves of 1M Li 2} SO ₄ at a scan rate of ^-1 , (B) and (C) are _{cyclic voltage curves of 1M Li 2} SO ₄ at a scan rate ^{of 5 to 500 mVs -1} , (D) is 1M Li ₂ Effect of scan rate on specific capacitance of silicon oxycarbide symmetric supercapacitor in SO ₄ (E) is the cyclic voltage curve of silicon oxycarbide symmetric supercapacitor at scan rate ^{of 200 mV s −1 (F) and (G) are} Cyclic voltage curves of silicon oxycarbide symmetric _{supercapacitors using 1M TEABF 4} and 1M TEABF ₄ at scan rates of 5 to 1,000 mVs ^-1 , (H) is the specific capacitance of silicon oxycarbide symmetric _{supercapacitors at 1M TEABF 4} effect of the scanning speed, (I) and (J) is 1M Li ₂ SO _4, and 1M TEABF silicon oxycarbide Nyquist plot of a symmetrical supercapacitor at _4, (K) is a silicone in 1M Li ₂ SO _4, and 1M TEABF ₄ Bode phase angle plot of oxycarbide symmetric supercapacitor, (L) is the specific capacitance of silicon oxycarbide symmetric supercapacitor given as a function of applied frequency at _{1 M Li 2} SO ₄ and 1 M TEABF _{4 ,}
Figure 10 is the specific capacitance of a silicon oxycarbide symmetric supercapacitor for different operating potential windows recorded using cyclic voltammetry (CV) scans at a scan rate ^{of 200 mVs −1 ;}
11 is a diagram showing the electrochemical analysis of a silicon oxycarbide symmetric _{supercapacitor in 1M Li 2} SO ₄ and 1M TEABF ₄ , (A) and (B) are 0.5 to 10 mA in _{1M Li 2} SO ₄ and 1M TEABF ₄ The constant current CD profile of the silicon oxycarbide symmetric supercapacitor as a function of the applied current, (C) is the effect of the indicated discharge current on the specific capacitance of the silicon oxycarbide symmetric _{supercapacitor in 1 M Li 2} SO ₄ and 1 M TEABF _{4 , (D)} and (E) is the cyclic stability of a silicon oxycarbide symmetric supercapacitor _{shown using more than 5,000 continuous charge-discharge cycles in 1M Li 2} SO ₄ or 1M TEABF ₄ , (F) is a silicon oxycarbide symmetric supercapacitor shown using _{1 M TEABF 4 .} the speed capability of the capacitor,
Fig. 12 (A) is a field-emission scanning electron micrograph of silicon oxycarbide, (B) is an overlay image of a silicon oxycarbide electrode before electrochemical testing, (C) is an elemental distribution of Si atoms present in the silicon oxycarbide electrode Measurement image, (D) is an elemental distribution measurement image of O atoms present in the silicon oxycarbide electrode, (E) is an elemental distribution measurement image of C atoms present in the silicon oxycarbide electrode, (F) is a silicon oxycarbide electrode A distribution measurement image of the F atoms present,
13 (A) is a field-emission scanning electron micrograph of silicon oxycarbide, (B) is an overlay image of a silicon oxycarbide electrode before electrochemical testing, (C) is a silicon oxycarbide after periodic testing in _{1M Li 2} SO _{4 .} Elemental distribution measurement image of Si atoms present in the electrode, (D) is an elemental distribution measurement image of O atoms present in the silicon oxycarbide electrode after periodic testing in _{1M Li 2} SO _{4 , (E) is an elemental distribution measurement image in 1M Li 2} SO ₄ Elemental distribution measurement image of C atoms present in silicon oxycarbide electrode after periodic testing, (F) is an elemental distribution measurement image of S atoms present in silicon oxycarbide electrode after periodic testing in _{1M Li 2} SO _{4 , (G) is} Elemental distribution measurement image of F atoms present in silicon oxycarbide electrode after periodic testing in 1M Li ₂ SO _{4 ,}
14 (A) is a field-emission scanning electron micrograph of silicon oxycarbide, (B) is an overlay image of a silicon oxycarbide electrode before electrochemical testing, (C) is a silicon oxycarbide electrode after periodic testing in _{1M TEABF 4} Elemental distribution measurement image of Si atoms present, (D) is an elemental distribution measurement image of O atoms present in silicon oxycarbide electrode after periodic testing in _{1M TEABF 4} , (E) is silicon oxycarbide after periodic testing in _{1M TEABF 4} Elemental distribution measurement image of C atoms present in electrode, (F) is an elemental distribution measurement image of N atoms present in silicon oxycarbide electrode after periodic test in _{1M TEABF 4} , (G) is silicon after periodic test in _{1M TEABF 4} Elemental distribution measurement image of B atoms present in the oxycarbide electrode, (H) is an elemental distribution measurement image of F atoms present in the silicon oxycarbide electrode after periodic testing in _{1M TEABF 4 ,}
15 is a Ragon plot of a silicon oxycarbide symmetric supercapacitor using _{1M Li 2} SO _{4 electrolyte;}
16 (A) is a Ragon plot of a silicon oxycarbide symmetric _{supercapacitor in TEABF 4} , (B) is a diagram showing a multifunctional electronic display powered by using a fully charged silicon oxycarbide in _{TEABF 4 .}

Hereinafter, preferred embodiments of the present invention will be described in detail. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted. Throughout the specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

The present inventors have applied for a patent on a supercapacitor containing siloxene in order to improve the capacitance of the conventional supercapacitor (Korean Patent No. 10-2053782), and the contents described in the preceding document are All may be referred to in the present invention.

In addition, as a result of repeated research to further improve the energy density of the supercapacitor, the present inventors have discovered that the supercapacitor can exhibit excellent energy density and power density by including a silicon oxycarbide thin film layer, leading to the present invention. .

Accordingly, the present invention provides a reaction step of reacting siloxene and an alginate to obtain silicon oxycarbide; a slurry preparation step of preparing an electrode material slurry by mixing the silicon oxycarbide, a conductive carbon material, and a binder; And it relates to a supercapacitor manufacturing method comprising a; and coating the electrode material slurry on a substrate and drying the thin film layer to prepare a silicon oxycarbide thin film layer.

Hereinafter, a method for manufacturing a supercapacitor according to the present invention will be described in detail.

The reaction step is a step of obtaining silicon oxycarbide by reacting siloxene and alginate.

The siloxene may be prepared by dissolving calcium by immersing a precursor containing calcium silicide in an acid, and the acid may be a strong acid of 4° C. or less, preferably hydrochloric acid. In addition, it is advantageous for the reaction to proceed efficiently and to obtain a desired form of siloxene if the reaction proceeds while maintaining a temperature of 0 to 2° C. while vigorously mixing under the hydrochloric acid.

The production of the siloxene may be carried out for 40 to 96 hours, preferably for 60 to 80 hours, and the reaction within the time range may be efficiently and relatively complete, and the time range If it is outside the reaction, it may be difficult to prepare a desired siloxene because the reaction is not complete.

In the production of siloxene, the progress of the reaction can be checked as the black color of calcium silicide changes to yellow of siloxene, and after the reaction is completed, it is washed with water and ultrasonic waves and separated from water. After drying, it can be recovered by a method of drying (siloxene drying step). In this case, in the cleaning process, ultrasonic waves may be performed at 15 to 25 kHz. In addition, the drying (siloxene drying step) may be performed at a drying temperature of 60 to 90° C. for 6 to 20 hours, and in this case, the reaction residue is removed and the siloxene is efficiently removed so that the siloxene is not damaged. Drying can proceed.

In the reaction step, the weight ratio of siloxene and alginate may be 1:5 to 1:20, preferably 1:10 to 1:15. If it is outside the above range, it may be difficult to prepare silicon oxycarbide, and in the present invention, the alginate may be sodium alginate, potassium alginate, magnesium alginate, triethanolamine alginate or propylene glycol alginate, preferably sodium alginate .

In addition, the reaction step may include a grinding step of pulverizing siloxene and alginate into fine powder; an annealing step of heating the fine powder at a heating rate of 1 to 5°C and annealing at 180 to 220°C for 1 to 5 hours; and a heat treatment step of heating the annealed fine powder at a heating rate of 5 to 20°C to heat treatment at 850 to 950°C for 4 to 8 hours.

The pulverization step is a step of pulverizing into a fine powder so that siloxene and alginate are mixed, and the annealing step is to remove the effect of heat history and pores remaining in the internal structure of siloxene and alginate. As a step, the pulverized fine powder may be heated at a heating rate of 1 to 5° C. for 1 to 5 hours at 180 to 220° C., preferably heated at a heating rate of 1 to 3° C. to 190 to 210° C. It can be carried out for 1 to 3 hours.

The heat treatment step is a step for preparing silicon oxycarbide by removing a functional group attached to the edge of siloxene and carbonizing a biopolymer. It is heated at a heating rate of 5 to 20° C. It can be heat-treated for 8 hours to 8 hours, preferably by heating at a heating rate of 5 to 15° C. to be heat-treated at 880 to 920° C. for 5 to 7 hours. When the temperature and time conditions are exceeded during heat treatment, it is not easy to remove the functional group attached to the edge of siloxene, and carbonization does not occur, so it may not be easy to manufacture silicon oxycarbide.

The heat treatment step may be performed in an inert gas atmosphere, preferably in an argon (Ar) gas atmosphere.

In the present invention, the slurry preparation step is a step of preparing an electrode material slurry by mixing silicon oxycarbide, a conductive carbon material and a binder, and the silicon oxycarbide prepared by the method described above may be used, and the silicon The properties of oxycarbide are described in detail below.

The conductive carbon material may include at least one selected from carbon black, graphene, and carbon nanotubes, and the binder is PVDF (Polyvinylidene Fluoride), PTFE (Polytetrafluoroethylene), PVA (Polyvinyl Alcohol) and SBR (Styrene Butadiene). It may include one or more selected from the group consisting of.

The electrode material slurry may contain 60 to 96% by weight of the silicon oxycarbide, preferably the electrode material slurry contains 70 to 96% by weight of the silicon oxycarbide, 2 to 15% by weight of the conductive carbon material, and the binder It may include 2 to 15% by weight, and more preferably, more specifically, the electrode material slurry comprises 86 to 94% by weight of silicon oxycarbide, 3 to 7% by weight of the conductive carbon material, and 3 to 7% by weight of the binder. may be included, and the stability performance and capacity characteristics of the supercapacitor may be further improved within the above range.

In the present invention, the thin film layer manufacturing step is a step of preparing a silicon oxycarbide thin film layer by coating the electrode material slurry on a substrate and drying it.

The thin film layer manufacturing step may be performed at a drying temperature of 60 to 90 ℃ for 6 to 20 hours, and at a drying temperature of 75 to 85 ℃ for 10 to 16 hours, in this case, the properties of silicon oxycarbide are maintained while super A silicon oxycarbide thin film layer may be manufactured to have characteristics such as strength required for the electrode of the capacitor, and the silicon oxycarbide thin film layer may be used as an electrode of a supercapacitor.

The method of manufacturing the supercapacitor may further include a separator arrangement step and an electrolyte solution injection step after the thin film layer manufacturing process, and at this time, the separator and the electrolyte solution may be applied as long as they are commonly applied to a supercapacitor, for example For example, the electrolyte may include TEABF ₄ or Li ₂ SO ₄ .

In the present invention, the silicon oxycarbide may have the following properties. The silicon oxycarbide may have a diffraction peak of 20 to 30°, and may have peaks ^{at 1390 to 1430 cm -1} and 1600 to 1700 cm ^{-1 in Fourier-transform infrared spectro supercapacitor opy (FT-IR) analysis, preferably} you may have a peak at 1400 to 1420 cm ^-1 and 1640 to 1670cm ^-1.

In addition, the silicon oxycarbide may have a Brunauer-Emmett-Teller (BET) surface area of 5.00 to 6.00 m ² /g, preferably 5.40 to 5.80 m ² /g. have.

It shows the characteristics of silicon oxycarbide of the present invention as one of the characteristics that can be changed depending on the conditions or method of the reaction in silicon oxycarbide that can be prepared by various methods.

In addition, in the present invention, the silicon oxycarbide has an O/Si atomic ratio confirmed by XPS analysis of 1 to 1.5, preferably 1.2 to 1.4, and a C/Si atomic ratio of 1.5 to 2.5, Preferably, it may be 1.9 to 2.2, and it can be seen that Si (silicon), O (oxygen) and C (carbon) are homogeneously distributed in the silicon oxycarbide thin film layer.

According to another aspect of the present invention, there is disclosed a supercapacitor comprising two or more electrodes containing an electrode material comprising silicon oxycarbide, a conductive carbon material and a binder, a separator positioned between the electrodes, and an electrolyte solution. .

In the present invention, the silicon oxycarbide may have the following properties. The silicon oxycarbide may have a diffraction peak of 20 to 30°, and may have peaks ^{at 1390 to 1430 cm -1} and 1600 to 1700 cm ^{-1 in Fourier-transform infrared spectro supercapacitor opy (FT-IR) analysis, preferably} you may have a peak at 1400 to 1420 cm ^-1 and 1640 to 1670cm ^-1.

In addition, the silicon oxycarbide may have a Brunauer-Emmett-Teller (BET) surface area of 5.00 to 6.00 m ² /g, preferably 5.40 to 5.80 m ² /g. have.

It shows the characteristics of silicon oxycarbide of the present invention as one of the characteristics that can be changed depending on the conditions or method of the reaction in silicon oxycarbide that can be prepared by various methods.

When the silicon oxycarbide according to the present invention is applied as an electrode material, excellent performance in stability and capacitance can be provided.

The supercapacitor according to the present invention ^{may have an energy density of 10 to 25 mJ/cm 2} , preferably 12 to 22 mJ/cm ² may have an energy density, and a power density of 5,000 to 20,000 W/kg. and may preferably have a power density of 6,000 to 18,000 W/kg. This is a much higher value compared to other silicon-based symmetric supercapacitor devices such as siloxene, SiC nanowires, and silicon nanotrises used as conventional electrodes.

From the experimental results of the present invention, the inventors of the present invention investigated the supercapacitor characteristics of silicon oxycarbide in detail, and confirmed the characteristics of silicon oxycarbide-based symmetric supercapacitors applicable in a wide voltage range of 2.0V or 3.0V. .

In addition, the silicon oxycarbide symmetric supercapacitor device showed excellent cyclic stability in which more than about 86% of the capacitance was maintained even after more than 5,000 charge-discharge cycles. It has high energy density, excellent capacitance ratio, and excellent cyclic stability when applied to supercapacitors, showing that it has great utility as a material to improve the properties of supercapacitors.

In the present invention, the capacitance was calculated according to Equations 1 and 2 below.

[Equation 1]

C = ∫Idv/(S X M X △V)

[Equation 2]

C = (I Х T _d ) / (M Х ΔV)

In Equations 1 and 2 above,

C is the capacitance (F g ^-1 ), I is the discharge current (A), T _d is the time required for discharge (seconds), M is the mass of the electroactive material (g), s is the scan rate (mV s ^-1) ), ΔV is the potential window (V).

In the present invention, energy density and power density were calculated according to Equations 3 and 4 below.

[Equation 3]

E = [C Х △V ² ] / 2

[Equation 4]

P = E / T _d

In Equations 3 and 4, E and P are the energy and power density of the supercapacitor device, C is the capacitance, ΔV is the potential window, and T _d is the discharge time (seconds).

In the present invention, the capacitance of the device with respect to frequency was calculated using EIS analysis according to Equation 5 below.

[Equation 5]

C = 1/2πfz

In Equation 5 above, C is the capacitance of the device, f is the applied frequency, and z is an imaginary plot of the impedance.

Hereinafter, specific examples according to the present invention will be described.

Materials and test methods

Calcium silicide (CaSi ₂ ) precursor was purchased from Kojundo Chemical Research Institute, Japan. Polyvinylidene fluoride (PVDF) was purchased from Sigma-Aldrich in Korea. Tetraethylammonium tetrafluoroborate (TEABF ₄ ) was purchased from Alfa Aesar Chemicals in Korea. Hydrochloric acid (HCl), carbon black, acetonitrile and N-methyl-2-pyrrolidone (NMP) were purchased from Daejeong Chemical Co., Ltd. in Korea. Ultrasonic irradiation was performed in a VCX 750 sonicator (Sonics and Materials, Inc, USA, 20 kHz, 750 W) using a direct immersion titanium horn.

The phase and crystallinity of the silicon oxycarbide thin film layer were determined using an X-ray diffractometer system (Empyrean) with Cu-Kα radiation (λ=1.5418 Å). The surface area analysis of the prepared silicon oxycarbide was measured using UPA-150, ASAP2010, and AutoporeIV of KBSI Jeonju Center. The functional groups of siloxene, alginate derived carbon and silicon oxycarbide were investigated using FT-IR spectroscopy (Thermo supercapacitor FT-IR spectrometer (Nicolet 6700)). Raman spectra were obtained using a LabRam HR Evolution Raman spectrometer (Horiba Jobin-Yvon, France). The chemical states of the elements in siloxene, alginate-derived carbon and silicon oxycarbide were analyzed using an X-ray photoelectron spectrometer (E-supercapacitor A-2000, VG Microtech Ltd.). Surface morphology and elemental distribution analysis were investigated using a high-resolution transmission electron microscope (JEM-2011, JEOL).

Example

1. Silicon oxycarbide (silicon oxycarbide) production

Siloxene was prepared through a topochemical reaction of _{CaSi 2} using cold hydrochloric acid. Briefly, 1 g of finely ground CaSi ₂ powder was immersed in HCL at 0 °C for 4 days with vigorous stirring. The color change from black-colored CaSi ₂ to yellow-green indicates slow dissolution of Ca in HCL. After the reaction was completed, green siloxene was separated by centrifugation using acetone and water. The separated powder was immersed in 100 mL of water, and then sonicated for one hour. Thereafter, green siloxene was separated by centrifugation and dried at 80° C. for 12 hours.

0.4 g of the siloxene and 5 g of sodium alginate were ground into a fine powder and annealed at 200° C. for 2 hours at a heating rate of 2° C. Then, the temperature was increased to 900°C at a rate of 10°C, heat-treated in an Ar atmosphere for 6 hours, and then cooled to room temperature to prepare silicon oxycarbide.

2. Preparation of silicon oxycarbide thin film layer (working electrode)

Using an agate mortar, 5 wt% carbon black, 5 wt% polyvinylidene fluoride (PVDF) and 90 wt% silicon oxycarbide dispersed in N-methyl-2-pyrrolidone (NMP) were ground to a homogeneous slurry was prepared, and the homogeneous slurry was coated on an aluminum (Al) substrate (aluminum foil) through a doctor blade to secure a uniform electrode thickness, and then the coated slurry was dried in a vacuum oven at 80° C. to remove the solvent. evaporated. After drying, the silicon oxycarbide electrode-coated aluminum foil was pressed on a rolling press machine (WCRP-1015G) and the electrode was cut into a circle with a diameter of 14 mm for the manufacture of a coin battery to prepare a silicon oxycarbide thin film layer.

In addition, a silicon oxycarbide thin film layer was prepared using a ^{stainless steel substrate (1x1 cm 2} ) instead of aluminum foil for the three-electrode test.

3. Fabrication of Coin All Terrain Symmetric Supercapacitor Device

A silicon oxycarbide-based symmetric supercapacitor device was fabricated as a coin-cell (CR2032) using a silicon oxycarbide thin film layer (using aluminum foil) as an electrode separated by a Celgard film, and 1M TEABF _{4 as an electrolyte.} The fabricated device was crimped using an Electric Coin Cell Crimping and Disassembling Machine (MTI Korea). Electrolyte and coin cell device fabrication was carried out in a glove box with a humidity of 1 ppm and lower than air.

In addition, a coin cell type symmetric supercapacitor device was manufactured _{using 1M Li 2} SO ₄ as an electrolytic nucleus and a silicon oxycarbide thin film layer using a stainless steel substrate (1x1 cm ^{2 ).}

Cyclic voltammetry (CV) at various scan rates, electrochemical impedance spectroscopy data (EIS) analysis (frequency of 0.01 Hz to 100 kHz and amplitude of 10 mV), and constant current at different current widths for silicon oxycarbide symmetric supercapacitor devices Electrochemical measurements such as expression charge and discharge (CD) measurements were performed using an Autolab PGSTAT302N electrochemical terminal.

Experiment result

1 shows the fabrication of a silicon oxycarbide thin film layer using carbon-thermal reaction at high temperature. Siloxene (prepared via topochemical de-intercalation of calcium from _{CaSi 2} ) and sodium alginate were used as silicon and carbon precursors for the preparation of silicon oxycarbide/carbon ceramics. A black silicon oxycarbide ceramic was produced by mixing a siloxene sheet and sodium alginate and heating at 900°C. In order to understand the mechanism of formation of silicon oxycarbide, as shown in Fig. 2, a mixture of siloxene, alginate (sodium alginate) and siloxene and alginate (sodium alginate) powders were subjected to heat Gravimetric analysis (TGA) was performed. The TGA thermogram of siloxene (FIG. 2) shows high thermal stability up to 900°C. In contrast, the thermogram of alginate (sodium alginate) shows (i) removal of OH- and CO- groups at 220°C, (ii) carbonization starting at 270°C, and (iii) alginate to carbon at 900°C. It features three stages of complete conversion. The thermogram of the powder containing a mixture of siloxene and alginate (sodium alginate) was similar to the bare alginate (sodium alginate) except that the residual weight percent was higher. The prepared silicon oxycarbide powder was thermally stable up to 900°C (see FIG. 3 ). The carbon-thermal prepared silicon oxycarbide powder was characterized using X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy and high-resolution transmission electron microscopy with elemental mapping analysis.

4A shows the X-ray photoelectron spectroscopy (XPS) spectra of thin film layers of siloxene, alginate-derived carbon and silicon oxycarbide. The presence of peaks corresponding to Si, O and C at 103, 530, and 284 eV, respectively, in the XPS spectrum of silicon oxycarbide indicates the carbothermal conversion of siloxene and alginate into silicon oxycarbide nanostructures. To elucidate the chemical states of the elements in the prepared silicon oxycarbide, core-level spectra of Si, O, and C were compared with those obtained from raw siloxene and alginate-derived carbon as shown in Fig. 4(BD). did Comparing the Si(2p) state of the exposed siloxene sheet and the silicon oxycarbide thin film layer in FIG. 4B shows that the chemical state of Si is changed after the carbon thermal reaction. The Si(2p) spectrum of siloxene (Fig. 4B, bottom) contains two peaks at 99 and 103 eV, which correspond to the Si-Si bonding and oxygenation/hydrogenation functions of siloxene, respectively. . Interestingly, the carbothermal reaction and conversion of siloxene into a silicon oxycarbide thin film layer has been shown to significantly change the bonding environment of Si. When new bonds occur between Si, O and C in the silicon oxycarbide thin film layer, the Si(2p) state is similar to that found in silicon oxycarbide. After the carbothermal reaction, the disappearance of the Si-Si bond indicated by the XPS peak at 99 eV indicates that the siloxene-intercalated group in siloxene is converted from silicon oxycarbide to O-Si-OC group. The Si(2p) spectra (shown in the upper part of Fig. 4B) of the carbon-thermal prepared silicon oxycarbide thin film layer, SiO ₃ C, SiO with peaks at 102.7, 101.8, 101.05 and 103.45 eV, respectively. _It indicates the presence of 2 C ₂ , SiOC ₃ and SiO _{x .} O(1s) spectra of the exposed siloxene, raw carbon, and silicon oxycarbide thin film layers were examined in detail to evaluate the change in the oxygen bonding level of the silicon oxycarbide thin film layer. The O(1s) spectrum of the siloxene sheet (Fig. 4C, bottom) contains two peaks at 532.5 and 533.5 eV corresponding to the _{Si-O 2} and Si-O _{x states, respectively.} The peaks at 532.7 and 533.8 eV in the O(1s) spectrum of alginate-derived carbon (Fig. 2C, middle) indicated the presence of C-OH and C=O groups, respectively. The O(1s) spectrum of the silicon oxycarbide thin film layer in Fig. 4C (top) shows that significant changes occurred during the carbonothermal reaction. The peaks at 532.5, 533.7 and 534.85 eV _{indicate the formation of C=O, Si-O 2} and Si-O _x groups, respectively, suggesting that siloxene is converted into a silicon oxycarbide thin film layer. The C(1s) spectrum of raw carbon (Fig. 4D, bottom) contains peaks corresponding to CC, C=C and CO bonds at 284.5, 285.2 and 290.5 eV, respectively. In contrast, the C(1s) spectrum of silicon oxycarbide (Fig. 4(D), top) contains peaks at 283.76, 284.47, 285.06 and 288.74 eV indicating the presence of C-Si, CC, C=C and CO groups. . This analysis also confirmed the formation of a silicon oxycarbide thin film layer through a carbon-thermal reaction between siloxene and alginate powder. The atomic composition of silicon oxycarbide produced by carbon heating is 22.85:29.22:47.93 (Si:O:C).

5A shows an X-ray diffractogram of a silicon oxycarbide thin film layer prepared by carbon heating. The presence of a broad diffraction peak of about 20 to 30° indicates the formation of amorphous silicon oxycarbide powder. The amorphous nature of silicon oxycarbide powder is derived from the disordered carbon phase of silicon oxycarbide; The diffraction diagram is almost identical to that of silicon oxycarbide prepared through thermal decomposition of polyphenylsesquisiloxane and calcination of tetraethyl orthosilicate. 5B compares Fourier-transform infrared spectroscopy (FT-IR) spectra of exposed siloxene, alginate-derived carbon and silicon oxycarbide. The spectrum of the exposed siloxene was 452 corresponding to the (Si-Si), (Si-H), (Si-O-Si), (Si-OH) and (OSi ₂ ≡Si-H) oscillations, respectively. , 867, 1,034, 1,639, and 2,140 cm ⁻¹ . These functional groups represent the formation of Kautsky-type siloxenes through topochemical removal of calcium from _{CaSi 2 .} The FT-IR spectrum of raw carbon (derived from the thermal decomposition of alginate) ^{contains a weak band at 1,014 cm −1} , which may be attributed to the presence of a carbonyl group (CO). The FT-IR spectra of silicon oxycarbide are significantly different from those of siloxene and carbon. (i) Vibration bands corresponding to the Si-H, Si-OH and OSi ₂ ≡Si-H groups of siloxene were absent in the FT-IR spectrum of silicon oxycarbide. (ii) the intensity of the Si-Si band of silicon oxycarbide was significantly lower than that of the exposed siloxane. (iii) The spectrum of silicon oxycarbide contained two new bands at ^{1,409 and 1,655 cm −1} corresponding to (Si-OC) and (C=O) of silicon oxycarbide. These changes further confirm the formation of silicon oxycarbide through a carbothermal reaction.

The Raman spectra of silicon oxycarbide powder in FIG. 5C have peaks at ^{376, 590, 962, 1,345 and 1,568 cm −1 .} The bands observed at 376 and 590 cm ⁻¹ originate from _{the Si-O x bond of silicon oxycarbide.} The band of 962 cm ^-1 is related to the LO mode of Si-O. The bands at 1,345 and 1,570 cm ⁻¹ correspond to the D and G bands of carbon in silicon oxycarbide, respectively.

The Raman spectra of silicon oxycarbide, siloxene sheets and alginate-derived carbon are compared in FIG. 6 . Fig. 5(DH) shows a high-resolution transmission electron spectroscopy (HR-TEM) micrograph of silicon oxycarbide powder, showing the existence of a thin-film-like structure with irregular lateral dimensions. The photomicrograph of Figure 5G shows the crumpled edges of silicon oxycarbide, which may be a side effect of the high temperature reaction. The inset of Figure 5G depicts a selected area electron diffraction (SAED) pattern of silicon oxycarbide, which shows a characteristic halo pattern representing the amorphous nature of the silicon oxycarbide thin film layer. To understand the distribution of Si, O and C atoms in silicon oxycarbide, elemental distribution measurements were performed while acquiring HR-TEM micrographs (Fig. 5H), and these distribution measurements are shown in Fig. 5 (IK), respectively. C, O and Si atoms are homogeneously distributed throughout the thin-film-like sheet, suggesting molecular-level transformation of siloxene to silicon oxycarbide. Figure 7 shows that the N ₂ adsorption-desorption isotherm of silicon oxycarbide is close to the typical type II isotherm, indicating monolayer formation on the macroporous surface at low pressure. The Brunauer-Emmett-Teller (BET; Brunauer-Emmett-Teller) surface area of the prepared silicon oxycarbide sample was 5.64 m ² g ^-1 , which was pyrolyzed polymethylphenyl silsesquioxane (1.8 and 4.3 m ^{2 , respectively).} g ^-1 ), which is comparable to that of silicon oxycarbides.

To investigate the charge storage capacity of individual silicon oxycarbide electrodes, _{three electrode analyzes were performed using Li 2} SO ₄ electrolyte and are presented in FIG. 8 . 8A shows cyclic voltage curves obtained for a silicon oxycarbide electrode at various scan rates (5-100 mVs ^{-1 ) of -1.0 to +1.0V.} The rectangular shape of the resulting voltage curve is consistent with the A-type behavior, which shows the capacitive or similar capacitive properties of the silicon oxycarbide electrode. Thus, the charge storage mechanism in the silicon oxycarbide electrode can be attributed to the combination of the double-layer capacitance from the carbon component of silicon oxycarbide and the intercalation capacitance from the Si-Si and/or Si-O component. In addition, no redox peak was observed in any voltage curve, indicating that there is no Faraday process in the silicon oxycarbide electrode. 8 (B and C) show the ideal polarization characteristics of the silicon oxycarbide electrode in the positive and negative voltage regions, respectively, and both electrodes provide a typical rectangular voltage curve. The periodic voltage curves presented in FIG. 8D show that the silicon oxycarbide electrode can function as a positive electrode and a negative electrode in an electrochemical energy storage (EES) device. Electrochemical impedance spectroscopy (EIS) measurements were performed with a silicon oxycarbide electrode to explain the capacitive properties and basic charge transfer mode on the electrode surface. Figure 8E shows a Nyquist plot obtained with a silicon oxycarbide electrode and shows the presence of solution resistance (Rs 2.488Ω) and charge transfer resistance (Rct 1.19Ω) with additional Warburg impedance. The Warburg line observed in the low frequency region is closer to the imaginary axis of impedance and represents the capacitive characteristics of the silicon oxycarbide electrode. FIG. 8F provides constant current charge and discharge (CD) profiles of silicon oxycarbide electrodes of -1.0 to +1.0 V recorded at various current ranges from 1.0 to 25.0 mA. The shape of the CD profile is quasi-triangle with no plateau region in good agreement with Figure 8A, indicating that the observed capacitance is due to the combination of double-layer formation and pseudo-capacitance.

In general, electrochemical studies using a two-electrode configuration are very suitable for performance evaluation of supercapacitors and for distinguishing electrode characteristics from device characteristics. Here, a symmetric supercapacitor device using two ideal silicon oxycarbide electrodes was fabricated using the following two electrodes: (i) aqueous Li ₂ SO ₄ (beaker-type cell) or (ii) organic TEABF ₄ (CR2032) coin cell).

Based on the above three-electrode analysis, these silicon oxycarbide symmetric supercapacitor devices are considered capable of operating within an operating voltage window (OVW) of 2.0V _{in Li 2} SO _{4 electrolyte, whereas TEABF 4} electrolyte exhibits an OVW of 3.0. extended to V.

9(AD) shows the electrochemical properties of silicon oxycarbide symmetric supercapacitors obtained in _{Li 2} SO _{4 electrolyte.} The cyclic voltage curve in Fig. 9A shows that the silicon oxycarbide symmetric supercapacitor can operate within an OVW of 2.0 V without any sign of gassing due to the neutral nature of _{Li 2} SO _{4 (acidic and basic electrolytes have limited OVW).} tend to).

9B and 9C show cyclic voltage curves obtained in Li ₂ SO ₄ electrolyte at various scan rates (5 to 500 mVs ^{−1 ), respectively.} 9B and 9C show cyclic voltage curves obtained in Li ₂ SO ₄ electrolyte at various scan rates (5 to 500 mVs ^{−1 ), respectively.} The rectangular shape of the voltage curve represents the ideal capacitance characteristic of the electrode. Figure 9D shows the effect of scan rate on the specific capacitance of a single silicon oxycarbide electrode ( _{obtained using a C electrode} = 4 x C _{device) and a silicon oxycarbide symmetric supercapacitor device.} At a low scan rate of 5 mV s ^{−1 , the silicon oxycarbide device exhibits a high device specific capacitance of 35.26 Fg −1} , from which the capacitance of a single electrode can be calculated as ^{141.07 Fg −1 .}

To determine the OVW of a silicon oxycarbide symmetric supercapacitor in the TEABF ₄ electrolyte, periodic voltage curves were obtained at different OVWs (0.0 to 3.0) with a scan rate of ^{200 mVs −1 , as shown in FIG. 9E .} The periodic voltage curve indicates that a rectangular curve exists even at an OVW of 3.0 V, indicating better capacity characteristics of the silicon oxycarbide symmetric _{supercapacitor in the TEABF 4 electrolyte, which is stable and has a large OVW compared to the aqueous electrolyte.}

In TEABF ₄ (Fig. 10), the specific capacitance of the silicon oxycarbide symmetric supercapacitor increased from 2.51 to 7.02 Fg ^{−1 as the OVW increased from 0.5 V to 3.0 V.} 9F and 9G show rectangular voltage curves obtained with silicon oxycarbide symmetric supercapacitors at various scan rates from ^{5 to 1,000 mVs −1 representing an ideal capacitor.} The effect of scan rate on specific capacitance of silicon oxycarbide symmetric supercapacitors is summarized in Fig. 9H. The device capacitance ratio of about 28.82 Fg ^-1 was obtained from the CV recorded at a scan rate of 5mVs ^-1. The corresponding capacitance of a single silicon oxycarbide electrode was 115.30 Fg ⁻¹ .

Nyquist plots obtained for silicon oxycarbide symmetric supercapacitors using Li ₂ SO ₄ and TEABF ₄ electrolytes are shown in FIGS. 9I and 9J, respectively. The Nyquist plot clearly shows three distinct regions corresponding to (i) high frequency, (ii) mid frequency, and (iii) low frequency regions of impedance. The solution resistances of silicon oxycarbide symmetric supercapacitors using Li ₂ SO ₄ and TEABF ₄ electrolytes were 1.36 and 2.5Ω, respectively, as measured from the high-frequency region of the Nyquist plot. The charge transfer resistance of the silicon oxycarbide symmetric _{supercapacitor was about 3.89Ω for the Li 2} SO ₄ electrolyte and 16.10Ω for the TEABF ₄ electrolyte. The higher solution and charge-transfer resistance for silicon oxycarbide symmetric supercapacitors _{using TEABF 4} electrolyte is attributed to the lower ionic conductivity and higher ionic radius of TEABF _{4 compared to Li 2} SO _{4 electrolyte.}

In addition, the low-frequency region indicates the presence of Warburg diffusion, which is closely related to diffusion-mediated capacitance of symmetric supercapacitors. Remarkably, the size of the Warburg lines is lower compared to that of Li ₂ SO _{4 compared to TEABF 4} , because of the differential ion diffusion kinetics of these electrolytes. 9K shows a Bode phase angle plot of a silicon oxycarbide symmetric supercapacitor with _{Li 2} SO _{4 and TEABF 4} electrolytes showing the change in phase angle as a function of applied frequency. At 0.01 Hz, the phase angles of silicon oxycarbide were -85.04° and -64.61° for _{Li 2} SO ₄ and TEABF _{4 electrolytes, respectively.} The capacitor response frequencies (f _o ) at a phase angle of -45° determined from the Bode phase angle plots shown in Fig. 9K _{were 0.83 and 0.43 Hz for the Li 2} SO ₄ and TEABF ₄ systems, respectively, and the relaxation times were 1.20 and 2.27 It was seconds. 9L shows the device specific capacitance of a silicon oxycarbide symmetric _{supercapacitor using Li 2} SO ₄ and TEABF ₄ electrolytes with respect to the applied frequency. In both cases, the device specific capacitance decreased with increasing frequency and high device capacitances of 21.2 and 9.01 Fg ⁻¹ _{were obtained at 0.01 Hz for silicon oxycarbide symmetric supercapacitors with Li 2} SO ₄ and TEABF _{4 electrolytes.} lost.

11A and 11B show the constant current CD profiles of silicon oxycarbide symmetric supercapacitor devices fabricated at different levels of used current using _{Li 2} SO ₄ (OVW 2.0V) and TEABF _{4 (OVW 3.0V) electrolytes.}

The CD profile obtained at high current is coarsely symmetrical, and more symmetric than the CD profile obtained at low current. These data show the role of surface and intercalation capacitance in silicon oxycarbide electrodes. The effect of the applied current range on the device specific capacitance is shown in Figure 11C. Silicon oxycarbide symmetric supercapacitors delivered device specific capacitances of ^{25.58 and 16.71 Fg −1} determined from discharge profiles recorded at currents of 0.5 mA, respectively, for devices comprising _{Li 2} SO ₄ and TEABF _{4 .} The device specific capacitance obtained with Li ₂ SO ₄ was higher than that obtained with _{TEABF 4} due to the higher ionic conductivity _{of aqueous Li 2} SO ₄ and lower ionic radius (about 0.06 nm) of ^{Li + ions.} The ionic radius of the TEA ⁺ ions is about 0.343 nm, but retains functionality at a relatively wide OVW of 3.0 V. 11D and 11E show the cyclic stability of silicon oxycarbide devices over 5,000 consecutive CD cycles. Interestingly, the device containing the _{TEABF 4} electrolyte exhibited a greater capacitance retention (about 92.8%) compared _{to the Li 2} SO _{4 based symmetric supercapacitor (86.2%).}

FE-SEM and elemental distribution measurements of silicon oxycarbide electrodes are shown before (FIG. 12) and after electrochemical testing _{in 1M Li 2} SO ₄ (FIG. 13) and 1M TEABF _{4 (FIG. 14).} No structural change was observed in any system of silicon oxycarbide electrodes after 5,000 consecutive CD cycles. Elemental distribution measurements (Fig. 12(BF)) of the extemporaneous assembled silicon oxycarbide electrode showed that the presence of Si, O, C and F atoms arises from the silicon oxycarbide active material and the PVDF binder. The _{silicon oxycarbide electrode cycle using Li 2} SO ₄ (FIG. 13(BG)) contained S atoms derived from the sulfate anion of the electrolyte. The _{silicon oxycarbide electrode cycle using TEABF 4} showed the presence of N, F and B atoms uniformly dispersed on the surface as shown in Fig. 14(BH).

These data show the structural stability of silicon oxycarbide electrodes even after uninterrupted CD cycles in both aqueous and organic electrolytes. To investigate the rate function of silicon oxycarbide symmetric supercapacitors in TEABF ₄ electrolyte, continuous CD profiles were recorded at various levels from low current to high current and vice versa, as shown in Fig. 11F. The electrodes exhibited excellent capacitance retention against different applied currents, highlighting the rate performance of silicon oxycarbide symmetric supercapacitors.

Energy/power density is often an important parameter that determines the practical application of symmetric supercapacitor devices. The energy/power performance indicators of TEABF ₄ based silicon oxycarbide symmetric supercapacitors were determined from CD analysis and displayed as Ragone plots in FIG. 16 . Similar data for a Li ₂ SO ₄ based system is shown in FIG. 15 . The Li ₂ SO ₄ based system yielded an energy density of ^{14.2 Wh kg −1} with a corresponding power density of ^{333 Wkg −1} at a constant current of 0.5 mA. As the current increased to 10mA, the silicon oxycarbide symmetric supercapacitor exhibited a maximum power density of 333 Wkg ^{-1 at an energy density of 9.61 Wh kg -1 .}

In contrast, the energy density of the silicon oxycarbide symmetric _{supercapacitor made of TEABF 4} ^{was as high as 20.89 Wh kg -1} , and the corresponding power density at a constant current of 0.5 mA was 750 W kg ^-1 . In addition, _{the silicon oxycarbide symmetric supercapacitor made of TEABF 4} maintained an energy density of 3.79 Wh kg ^-1 at a current of 10 mA and a power density of 15,000 W kg ^-1.

No. electrode electrolyte work
electric potential
window maximum energy density
(Wh kg ^-One ) maximum power
density
(W kg ^-One ) One activated carbon Et ₄ NBF ₄ /AN 0.0 to 2.3 V 8 1418 2 porous
carbon EMI-BF ₄ 0.0 to 3.0 V 11.4 9800 3 graphene sheet BMIBF ₄ 0.0 to 4.0 V 16.5 1600 4 reduced
graphene oxide [SET ₃ ][TFSI]-GO 0.0 to 2.5 V 17.7 875 5 Ti ₃ C ₂ T _x /MWCNT Et ₄ NBF ₄ 0.0 to 1.8 V 3 - 6 Siloxene
Sheet TEABF ₄ 0.0 to 3.0 V 5.08 375 7 MoS ₂ sheet TEABF ₄ 0.0 to 3.0 V 18.43 1125 8 rGO LiClO ₄ /PC 0.0 to 2.5 V 9.4 678 9 coPIL-RGO BMIMBF ₄ /AN 0.0 to 2.5 V 14.7 5400 10 Maxwell (commercial) - 2.7 V 4.45 900 11 Panasonic
(commercial) - 2.5 V 2.3 514 12 silicon oxycarbide Li ₂ SO ₄ 0.0 to 2.0 V 14.21 6666 13 silicon oxycarbide TEABF ₄ 0.0 to 3.0 V 20.89 15000

S. No. electrode electrolyte work
electric potential
window energy
density
(mJ cm ^-2 ) power density
(mW cm ^-2 ) One Graphene/Si Nanowires EMIMBF ₄ 0.0 to 2.7 V 3.6 One 2 PEDOT/Si nanowires PYR ₁₃ TFSI 0.0 to 1.5 V 9 0.8 3 Diamond/Si Nanowires Et ₃ NHTFSI 0.0 to 4.0 V 15 3 4 Ppy/Si Nanowires PYR ₁₃ TFSI 0.0 to 1.5 V 11 0.8 5 Ppy/Si nanotris PYR ₁₃ TFSI 0.0 to 1.5 V 15 0.8 6 PEDOT/D@Si nanowires N ₁₁₁₄ TFSI 0.0 to 2.5 V 26 1.3 7 MnO ₂ /Si nanowires PYR ₁₃ TFSI/
LiClO4 0.0 to 2.0 V 32 0.4 8 SiC Nanowires KCl 0.0 to 0.6 V 2.3 1.1 9 Siloxene TEABF ₄ 0.0 to 3.0 V 9.82 4.03 10 silicon oxycarbide TEABF ₄ 0.0 to 3.0 V 48.82 9.74

Tables 1 and 2 above are tables compared to silicon oxycarbide symmetric supercapacitor devices for gravimetric and areal measurements of state-of-the-art supercapacitors using organic/ionic liquid electrolytes. The energy densities of silicon oxycarbide symmetric supercapacitors _{using TEABF 4} electrolytes were activated carbon (8 Wh kg ^-1 ), porous carbon (11.4 Wh Kg ^-1 ), graphene (16.5 Wh kg ^-1 ), and reduced graphene oxide. , (17.7 Wh kg ^-1 ), rGO (9.4 Wh kg ^-1 ), coPIL-RGO (14.7 Wh kg ^-1 ), Ti ₃ C ₂ Tx/MWCNT (3 Wh kg ^-1 ), siloxene ( 5 Wh kg ⁻¹ )), 2D-MoS ₂ (18.43 Wh kg ⁻¹ ) and commercial supercapacitors were fabricated and had higher energy densities than the recently reported symmetric supercapacitors. In addition, the power density of the silicon oxycarbide symmetric supercapacitor ^{reached a maximum of 15,000W kg -1} , indicating its suitability as a power source for next-generation automobiles.

The data in Table 1 above provide evidence for the superior power performance of silicon oxycarbide symmetric supercapacitors compared to other supercapacitor systems using electrodes such as graphene, rGO, coPIL-RGO, MoS _{2 , MXene and siloxene.} provides

The data in Table 2 show that the areal energy-power performance indicators of silicon oxycarbide symmetric supercapacitors are higher than those of other silicon-based symmetric supercapacitors.

16B shows a real-time application of a silicon oxycarbide symmetric supercapacitor to power a multifunction electronic display indicating ambient temperature and relative humidity. The silicon oxycarbide symmetric supercapacitor was initially charged to 3.0V using an applied current of 1mA. The stored energy is sufficient to power electronic displays for more than 12 minutes, demonstrating the applicability of silicon oxycarbide symmetric supercapacitors.

As described above, the supercapacitor and the manufacturing method thereof according to the present invention can provide a supercapacitor exhibiting excellent energy density and power density and a manufacturing method thereof by including a silicon oxycarbide thin film layer, and thus the supercapacitor according to the present invention You may find it useful in the development of high-performance energy storage devices.

The preferred embodiment of the present invention has been described in detail above. The description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains will understand that other specific forms can be easily modified without changing the technical spirit or essential features of the present invention.

Accordingly, the scope of the present invention is indicated by the claims described later rather than the detailed description, and all changes or modifications derived from the meaning, scope, and equivalent concept of the claims are included in the scope of the present invention. should be interpreted

Claims (14)

a reaction step of reacting siloxene and alginate to obtain silicon oxycarbide;
a slurry preparation step of preparing an electrode material slurry by mixing the silicon oxycarbide, a conductive carbon material, and a binder; and
A thin film layer manufacturing step of coating the electrode material slurry on a substrate and drying the silicon oxycarbide thin film layer;
Supercapacitor manufacturing method comprising a. According to claim 1,
The siloxene is a supercapacitor manufacturing method, characterized in that it is prepared by dissolving calcium by immersing a precursor containing calcium silicide in acid. 3. The method of claim 2,
The method of manufacturing a supercapacitor, characterized in that the acid is a strong acid of 4 ℃ or less. According to claim 1,
The method for manufacturing a supercapacitor, characterized in that the weight ratio of the siloxene and the alginate is 1:5 to 1:20. According to claim 1,
The reaction step is
pulverizing step of pulverizing siloxene and alginate into fine powder;
an annealing step of heating the fine powder at a heating rate of 1 to 5°C and annealing at 180 to 220°C for 1 to 5 hours; and
a heat treatment step of heating the annealed fine powder at a heating rate of 5 to 20° C. and heat treating at 850 to 950° C. for 4 to 8 hours;
Supercapacitor manufacturing method comprising a. 6. The method of claim 5,
The heat treatment step is a supercapacitor manufacturing method, characterized in that performed in an inert gas atmosphere. According to claim 1,
The electrode material slurry is a supercapacitor manufacturing method, characterized in that it contains 60 to 96% by weight of the silicon oxycarbide. According to claim 1,
The method of manufacturing a supercapacitor, characterized in that the silicon oxycarbide has a diffraction peak of 20 to 30°. According to claim 1,
The silicon oxycarbide The method for producing a super capacitor characterized in that it has a peak in FT-IR analysis, when 1390 to 1430cm ^-1 and 1600 to 1700cm ^-1. According to claim 1,
The silicon oxycarbide is a supercapacitor manufacturing method, characterized in that the Brunauer-Emmett-Teller (BET) surface area is 5.00 to 6.00 m ^{2 /g.} According to claim 1,
The silicon oxycarbide has an O/Si atomic ratio of 1 to 1.5 and a C/Si atomic ratio of 1.5 to 2.5 as confirmed by XPS analysis. According to claim 1,
The supercapacitor manufacturing method further comprises a separator arrangement step and an electrolyte solution injection step after the electrode manufacturing step, wherein the electrolyte solution comprises TEABF ₄ or Li ₂ SO ₄ . A supercapacitor comprising at least two electrodes containing silicon oxycarbide, an electrode material including a conductive carbon material and a binder, a separator positioned between the electrodes, and an electrolyte. 14. The method of claim 13,
The supercapacitor has an energy density of 10 to 25mJ/cm ² A supercapacitor, characterized in that it has a power density of 5,000 to 20,000W/kg.

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