Composite materials, methods of manufacturing and use in battery applications

Abstract

The present invention generally relates to composite materials and methods for making the same. The present invention also relates to the use of the composite materials as electrode materials in battery applications. In particular, the method for making the composite materials comprises mixing porous carbon with a rylene dye to form a mixture, heating the mixture, and carbonizing the mixture.

Description

Technical Field

[0001] In general, the present invention relates to composite materials and methods of making the same. The present invention also relates to the use of the composite materials in battery applications. Background Art

[0002] Due to the abundant sodium resources on the earth, sodium-ion battery (SIB) is considered to be an effective supplement to lithium-ion battery (LIB). Despite the progress in developing electrolytes and cathode materials, there is also an urgent need for comprehensive high-performance anode materials, which play an important role in further improving the energy density in SIBs. However, due to the positive formation energy of Na-graphite intercalation compound (Na-GIC), commercially available graphite anodes in LIBs are not suitable for SIBs. Compared with alloy-based and conversion-based anode materials with high platform voltage and poor cycling stability, hard carbon has a lower platform voltage and acceptable capacity (about 300mAh g -1 ) and is still considered to be one of the most promising candidates for anode materials for SIBs.

[0003] The low voltage plateau capability of the anode can enable higher energy density in full cell. According to the typical “intercalation / pore-filling” model for sodium ion storage mechanism, the tilted region is composed of Na + The low voltage plateau is attributed to the embedding of Na + The pore-filling process into the closed pores blocked by graphite nanodomains. Therefore, several strategies to increase the platform capacity by forming more closed pores have been proposed. For example, in previous works, pore formers or pre-oxidation / high-temperature carbonization were used to adjust the closed pore structure of hard carbon and thus achieve a large reversible platform capacity. Some workers obtained hard carbon fibers with a large number of closed pores by heating waste silk fabrics even at ultra-high temperatures of 2000°C. Despite the aforementioned progress in synthesizing hard carbon with improved reversible platform capacity, high carbonization temperatures (much higher than 1300°C) are unsafe and environmentally unfriendly. In addition, poor rate performance is always accompanied by high platform capacity. Therefore, continued efforts are still needed to design the target structure of hard carbon at mild temperatures to achieve large platform capacity and satisfactory rate performance.

[0004] It would be desirable to overcome or ameliorate at least one of the problems described above. Summary of the Invention

[0005] In this work, a strategy is proposed to increase the ultramicropores inside carbon materials by melt-diffusion of aromatic hydrocarbons into microporous carbon, followed by further carbonization. As a result, the rationally designed carbon anode shows a low voltage plateau at about 0.1 V in the discharge / charge curves and a high voltage plateau at 30 mA g, respectively. -1 and 2000mA g -1 346mA g -1 and 125mA g -1 In addition, high loading electrodes (about 19 mg cm -2 ) also showed a capacity of 6.14 mAh cm at 25 °C. -2 and 5.32 mAh cm at −20 °C -2 The high areal capacity of the coin-type full cell enables the realization of approximately 97.1 mA g -1 The proposed melt diffusion-carbonization strategy is facile and energy-efficient for preparing high-performance carbon anode materials with great practical potential for SIBs. Electrodes formed from the composite materials disclosed herein can be used to improve the capacity and rate performance in room temperature / low temperature sodium ion storage.

[0006] The present invention discloses a method for manufacturing a modified porous carbon composite material, the method comprising:

[0007] a) mixing porous carbon and rylene dye to form a mixture;

[0008] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0009] c) carbonizing the mixture at a temperature of about 700°C to about 1300°C.

[0010] Advantageously, the heating step under an inert atmosphere causes the rylene dye to become molten and thereby coat the porous carbon and diffuse into the pores of the porous carbon. The pores blocked by the rylene dye are then carbonized within the porous carbon to convert the open pores into closed pores. This method changes the pore size of the porous carbon without completely blocking the pores and is also less energy intensive than high temperature annealing. The pore size is also reduced without blocking, thereby allowing the bare Na + The anodes for sodium ion storage formed using this method exhibit increased plateau capacity, improved cycling stability, satisfactory rate capability, and high areal capacity.

[0011] In some embodiments, the composite material comprises ultramicropores having a pore size (based on CO2 adsorption) of about 0.2 nm to about 0.8 nm; and

[0012] In some embodiments, the composite material has a BET(CO2) specific surface area of ​​about 10 m2 g -1 About 220m 2 g -1 .

[0013] In some embodiments, the mass ratio of porous carbon to rylene dye is from about 1:1 to about 1:4.

[0014] In some embodiments, the porous carbon is selected from activated carbon, mesoporous carbon, carbonized sugar, high specific surface area carbon, and low specific surface area carbon.

[0015] In some embodiments, the rylene dye is selected from the group consisting of perylenetetracarboxylic dianhydride (PTCDA), perylene diimide, terrylendiimide, terrylen, perylene, quaterrylen, and naphthalin.

[0016] In some embodiments, the mixture is mechanically blended.

[0017] In some embodiments, the inert atmosphere is argon.

[0018] In some embodiments, the heating step is performed for about 2 hours to about 10 hours.

[0019] In some embodiments, the carbonizing step is performed for at least 3 hours.

[0020] In some embodiments, the carbonizing step is performed at a rate of about 3°C / minute to about 10°C / minute.

[0021] The present invention also discloses a modified porous carbon composite material, wherein the modified porous carbon composite material comprises:

[0022] a) porous carbon structure; and

[0023] b) carbonized rylene dyes;

[0024] The carbonized rylene dye at least covers the inner pores of the porous carbon structure.

[0025] In some embodiments, the composite material comprises ultramicropores having a pore size (based on CO2 adsorption) of about 0.2 nm to about 0.8 nm.

[0026] In some embodiments, the composite material has a BET(N2) specific surface area of ​​about 5 m 2 g -1 About 80m 2 g -1 .

[0027] In some embodiments, the composite material has a BET(CO2) specific surface area of ​​about 10 m 2 g -1 About 220m 2 g -1 .

[0028] In some embodiments, the mass ratio of the porous carbon structure to the at least partially carbonized rylene dye is from about 1:1 to about 1:4.

[0029] In some embodiments, the composite material has a ratio of BET (CO 2 ) specific surface area to BET (N 2 ) specific surface area of ​​about 0.1 to about 50.

[0030] In some embodiments, the XRD pattern of the composite material shows the presence of a (002) peak derived from the carbon of the carbonized rylene dye and a (002) peak of the porous carbon structure.

[0031] In some embodiments, the (002) peak derived from the carbon of the carbonized rylene dye is about 25.2°.

[0032] In some embodiments, the (002) peak of the porous carbon structure is about 21.2°.

[0033] In some embodiments, the total volume of the composite material (based on N2 adsorption) is about 0.01 cm 3 g -1 to about 0.13cm 3 g -1 .

[0034] In some embodiments, the total volume of the composite material (based on CO2 adsorption) is about 0.08 cm 3 g -1 to about 0.4cm 3 g -1 .

[0035] In some embodiments, the composite material has an R-value of from about 2 to about 5.

[0036] In some embodiments, the composite material has a skeletal density of about 1.8 g cm -3 to about 2.5gcm -3 .

[0037] The present invention also discloses a method for manufacturing an electrode, the method comprising:

[0038] a) mixing a composite material as disclosed herein with a binder solution to form a slurry;

[0039] b) applying the slurry to the surface of the electrical conductor; and

[0040] c) drying the slurry.

[0041] In some embodiments, the weight ratio of composite material to binder solution is from about 80:20 to about 95:5.

[0042] In some embodiments, the concentration of the binder solution is from about 10 mg / mL to about 20 mg / mL.

[0043] In some embodiments, the binder solution comprises a binder selected from sodium carboxymethylcellulose and / or polyvinylidene fluoride (PVDF).

[0044] In some embodiments, the drying step is performed at about 40°C to about 80°C.

[0045] In some embodiments, the drying step is performed for about 2 hours to about 6 hours.

[0046] In some embodiments, the drying step further comprises vacuum drying the slurry at about 100° C. to about 140° C. for at least 8 hours.

[0047] The present invention also discloses an electrode, which comprises:

[0048] a) a composite material as disclosed herein;

[0049] b) a binder; and

[0050] c) electrical conductors;

[0051] wherein the composite material and the binder are uniformly combined; and

[0052] The composite material and the adhesive cover at least one surface of the conductor.

[0053] In some embodiments, the weight ratio of composite material to binder is from about 80:20 to about 95:5.

[0054] In some embodiments, the electrode has a current density of about 2000 mA g -1 The current density is greater than 100 mAh g -1 capacity or at about 30mA g -1 The current density is greater than 300 mAh g -1 capacity.

[0055] In some embodiments, the electrode retains at least 80% of its initial capacity after 200 cycles.

[0056] In some embodiments, the mass loading of the composite material and binder on the conductor is at least 15 mg cm -2 .

[0057] In some embodiments, the electrode has a current density of about 0.1 mA cm -2 At a current density of about 6 mAh cm -2 The area capacity is about 0.5 mA cm -2 At a current density of about 3 mAh cm -2 area capacity.

[0058] In some embodiments, at least 80% of the areal capacity is retained at about -20°C.

[0059] The present invention also discloses a battery, comprising:

[0060] a) organic cathode;

[0061] b) an anode comprising a composite material as disclosed herein; and

[0062] c) Sodium metal applied to at least one surface of the anode.

[0063] In some embodiments, the organic cathode comprises a rylene dye.

[0064] In some embodiments, the mass loading ratio of the organic cathode to the anode is from about 1:2 to about 1:3.

[0065] In some embodiments, the N / P ratio (areal capacity ratio of the negative electrode to the positive electrode) is from about 1.1:1 to about 1.2:1.

[0066] In some embodiments, during charging and / or discharging of the battery, the battery is characterized by 23 Peak at 4.44 ppm in NaMAS NMR.

[0067] In some embodiments, when the battery is fully discharged, the battery is characterized by 23 A peak at 4.44 ppm and a peak from about -20 ppm to about -30 ppm in Na MAS NMR. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Embodiments of the present invention will now be described by way of non-limiting examples with reference to the accompanying drawings, in which:

[0069] Figure 1. Characterization of AC, GC, and ACGC900: (A) Scheme of the melt-diffusion-carbonization strategy (T represents the carbonization temperature). Micrometer-scale SEM images of (B) AC and (C) ACGC900. (D) TEM image of the thin edge region of a typical ACGC900 particle and the corresponding selected area electron diffraction (SAED) pattern (inset). (E) N2 adsorption / desorption isotherms, (F) pore size distribution from N2 adsorption / desorption measurements, and (G) peak fitting of the (002) peak in the XRD pattern.

[0070] Figure 2 Electrochemical performance of AC, GC and ACGC900 electrodes in SIB: (A) at 50 mA g -1 (B) At 0.1 mV s -1 At a scan rate relative to Na / Na + CV in the voltage range of 0.001V to 3.0V. (C) at 50mA g -1 Cycling performance under

[0071] Figure 3. Effects of carbonization temperature and pore volume on electrochemical performance: (A) ACGCx at 50 mA g -1 (B) The relationship between the tilted capacity contribution rate and the R value calculated by XRD. (C) The constant current discharge-charge curves of ACGC, HCGC, and LCGC electrodes at 50 mA g -1 (D) Relationship between plateau capacity and filler / host mass ratio. (E) Rate performance and (F) comparison of the rate performance of the LCGC anode with that of other recently reported hard carbon anodes for SIBs.

[0072] Figure 4. Analysis of sodium ion storage mechanism: (A) at 0.1 mV s -1 to 1.0mV second -1 CV curves at varying scan rates, (B) log(i) versus log(v) plots and corresponding linear fits, and (C) D calculated from GITT measurements during the discharge-charge process. Na + (D to E) In-situ XRD patterns and capacity-potential curves in the voltage window of 0.001V to 3V. (F) Capacity at different potentials 23 Ex situ solid-state NMR spectroscopy of Na;

[0073] Figure 5. Thick electrode and full cell testing. Mass loading is 19 mg cm -2(A) Cycling performance and (B) rate performance of thick electrodes. (C) Cycling performance of thick electrodes at 0.2 mA cm in the temperature range of -20°C to 40°C. -2 Constant current discharge / charge curves and (D) capacity retention rate under (E) 10mA g -1 (F) The constant current discharge / charge curves of the full cell in the voltage range of 0.5 V to 3.0 V;

[0074] Figure 6 (A) CO2 adsorption isotherm and (B) corresponding pore size distribution of ACGC900.

[0075] Figure 7 Schematic diagram of the definition of the parameter R used to experimentally determine the degree of graphitization of a carbon sample. The R value (R = B / A) can determine the degree of graphitization of a sample. Lower R values ​​indicate a lower degree of graphitization or fewer stacked graphene layers. R is measured as the ratio of the (002) Bragg peak intensity to background;

[0076] Figure 8 Raman spectra of AC, GC, and ACGC900;

[0077] Figure 9 Rate performance of AC, GC, and ACGC900 electrodes at different current densities;

[0078] Figure 10 Low-resolution SEM images (A1 to E1) and high-resolution SEM images (A2 to E2) of AC, ACGC750, ACGC900, ACGC1050, and ACGC1200, respectively. (Scale bars: 10 μm for A1 to E1, 1 μm for A2 to E2);

[0079] Figure 11 N2 adsorption / desorption isotherms and corresponding pore size distribution of ACGCx. The hysteresis between the adsorption and desorption branches of the isotherms indicates the presence of confined pores.

[0080] Figure 12 CO2 adsorption isotherms and corresponding pore size distributions of ACGCx;

[0081] Figure 13 .XRD pattern of ACGCx;

[0082] Figure 14 (A) Specific capacity and (B) contribution rate of ACGCx contributed by the slope region and the platform region.

[0083] Figure 15.(A)AC, (B)GC, (C)ACGC750, (D)ACGC900, (E)ACGC1050, (F)ACGC1200, (G)HCGC and (H)LCGC at 50mA g -1 The first five constant current discharge-charge curves under ;

[0084] Figure 16 Relationship between ICE value and BET surface area obtained from N2 adsorption / desorption tests;

[0085] Figure 17 ACGCx at 50mA g -1 (A) Rate performance and (B) Cycling performance under 2000 mA g -1 It can also reach about 118mAh g -1 In addition, at 50mA g -1 After the next 200 cycles, it can maintain about 97.3% of the initial capacity;

[0086] Figure 18 (A, B) N2 adsorption / desorption isotherms and (C, D) corresponding pore size distributions for AC, CMK8, HC, LC, ACGC, CMK8GC, HCGC, and LCGC. The hysteresis between the adsorption and desorption branches of the isotherms indicates the presence of confined pores.

[0087] Figure 19 Pore ​​size distribution of CMK8 and CMK8GC;

[0088] Figure 20 TEM images of (A) CMK-8 and (B) CMK8GC (scale bar: 50 nm). As shown in FIG21 , the CMK8GC electrode derived from a mesoporous-dominated carbon host (CMK-8) did not show a plateau capacity during the discharge-charge process. This is likely because the mesopores inside CMK-8 (cubic 1a3d, rod-shaped) are interconnected and large enough to accommodate the quasi-graphitic nanodomains ( Figures 19 to 20 ). Therefore, when nanodomains with layered graphene structures were introduced into CMK8GC instead of nanocavities, no platform appeared;

[0089] Figure 21. (A) of CMK8GC electrode at 50 mA g -1 Constant current discharge-charge curves, (B) cycle performance, and (C) rate performance under φ(A) = φ(B) = φ(C) = φ(D) = φ(E ...

[0090] Figure 22. ACGC, HCGC, and LCGC electrodes at 50 mA g -1(A) rate performance and (B) cycle performance under ;

[0091] Figure 23 The third sodiumization process of ACGC electrode for sodium-ion batteries is relatively + Current step diagram at 0.304V;

[0092] Figure 24 GITT potential curve of ACGC;

[0093] Figure 25 ACGC during the third sodiumization process (A) relative to Na / Na + Potential in GITT at 0.304 V versus τ 1 / 2 Linear behavior;

[0094] Figure 26 Schematic diagram of the proposed sodium ion storage mechanism;

[0095] Figure 27 .Discharge-charge curves of LCGC thick electrode at different current densities; and

[0096] Figure 28 D calculated from GITT test during the discharge-charge process of thick LCGC electrode at different temperatures Na +value. DETAILED DESCRIPTION

[0097] Disordered porous carbons such as biomass-derived carbons and porous coordination polymer-derived carbons can be easily synthesized at mild temperatures below 1000 °C. These porous carbon materials offer improved diffusion kinetics and satisfactory rate performance in SIBs, thanks to the presence of enhanced porosity. However, since capacitive ions are only present in bare Na + and solvated Na + The adsorption / desorption of Na+ on the surface sites of the coexisting micropores is therefore a sloped curve. In fact, the presence of electrolyte has a significant effect on the ionic interactions inside the pores. It is assumed that if the electrolyte can be blocked outside the micropores, a storage mechanism different from capacitive adsorption can be introduced. It is believed that the pore size of the carbon material has a significant effect on the solvation of Na+. + It shows that the ion screening effect and the pore size have a great influence on the electron distribution inside the pore. Specifically, when the pore size is smaller than the solvated Na + When , desolvation will occur around the pore. In addition, according to the calculation and simulation results, the Na + The concentration increases as the pore width decreases. In addition, as the pore width decreases, the electrons tend to spread to all the neighboring Na + Instead of a single Na +Above. + The tendency of aggregation inside the pores thus becomes significant. Given that the micropores (>1 nm) in porous carbon can be tuned into ultramicropores with smaller pore size and pore width, bare Na can be introduced during the sodiation / desodiation process. + filling and aggregation and still ensure that Na + Therefore, adjusting the pore size and pore width of porous carbon can be an effective strategy to increase the platform capacity without sacrificing rate performance. Compared with N2 ) and higher operating temperature (273 K for CO2 compared to 77 K for N2), CO2 adsorption measurements are highly effective for detecting the presence of ultramicropores (<0.8 nm).

[0098] The present invention discloses a method for manufacturing a modified porous carbon composite material, the method comprising:

[0099] a) mixing porous carbon and rylene dye to form a mixture;

[0100] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0101] c) at least partially carbonizing the mixture at a temperature of about 700°C to about 1300°C.

[0102] In some embodiments, a method of making a modified porous carbon composite material comprises:

[0103] a) mixing porous carbon and rylene dye to form a mixture;

[0104] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0105] c) carbonizing the mixture at a temperature of about 700°C to about 1300°C.

[0106] The inventors have found that the pore size and pore size (or width) of porous carbon can be adjusted by the above method. In this regard, the naphthylene dye enters the pores of the porous carbon, and when at least partially carbonized, the naphthylene dye narrows the pore width and pore size of the pores. This can be further controlled by changing the temperature. The present invention provides the advantages of high platform capacity, high specific capacity and high average voltage in full-cell batteries by blocking the open pores of the porous carbon into closed pores and then converting the capacitive sodium storage process into a pore-filling mechanism. Since the synthesis process is easy, it is also scalable for industrial processes. The low synthesis temperature compared to conventional (1500°C or higher) also provides energy-saving benefits. The formed electrode can have a high mass loading and low temperature resistance, while the full-cell battery can have good electrochemical performance, indicating that practical applications are reasonable.

[0107] As used herein, rylene dyes are dyes based on a rylene structure of naphthalene units attached in peri-position. Additional naphthalene units are added to the homologues to form compounds such as perylene, terrylene and quaterrylene - or poly(peri-naphthalene)-. Rylene dyes can be functionalized with polar and / or hydrophilic moieties such as carboxylate, amide, amine, anhydride and diacetamide groups.

[0108] In some embodiments, the rylene dye is selected from perylene tetracarboxylic dianhydride (PTCDA; melting point 350°C; MW 392 g / mol), perylene diimide, terrylene diimide, terrylene, perylene, quaterrylene, and naphthalene. Other rylene dyes exhibiting similar properties (e.g., melting point, molecular size, etc.) may also be used. In some embodiments, the rylene dye is perylene tetracarboxylic dianhydride (PTCDA). PTCDA comprises a perylene core to which two anhydride groups are attached (one on each side). PTCDA occurs in two crystalline forms (α and β). Both have P21 / c monoclinic symmetry and a molecular weight of approximately 1.7 g / cm 3 Functionalized PTCDA and its derivatives are also included in this range.

[0109] Porous carbon is a carbon characterized by its highly enhanced microporous structure and mesoporous structure. The pores are capable of absorbing fluids (liquids and / or gases) or allowing fluids to pass through. The main characteristics of porous carbon are huge surface area and graded porosity. Pores can be divided into three categories such as macropores, mesopores and micropores. Macroporous materials have a pore size greater than 50nm, mesoporous materials have a pore size less than 50nm and greater than 2nm, and microporous materials have a pore size less than 2nm and greater than 0.8nm. Ultraporous materials have a pore size less than 0.8nm. In addition, the pores can be interconnected.

[0110] In some embodiments, the porous carbon is selected from activated carbon, mesoporous carbon, carbonized sugar, high specific surface area carbon, and low specific surface area carbon. In other embodiments, the porous carbon is mesoporous carbon and / or microporous carbon. The activated carbon can be microporous carbon. In other embodiments, the porous carbon is microporous carbon, carbonized sugar, high specific surface area carbon, and low specific surface area carbon.

[0111] In some embodiments, the porous carbon is mesoporous carbon. The pore size of the mesoporous carbon can be from about 2 nm to about 50 nm. In other embodiments, the pore size is from about 2 nm to about 45 nm, from about 2 nm to about 40 nm, from about 2 nm to about 35 nm, from about 2 nm to about 30 nm, from about 2 nm to about 25 nm, from about 2 nm to about 20 nm, from about 2 nm to about 15 nm, from about 2 nm to about 10 nm, or from about 2 nm to about 5 nm.

[0112] In other embodiments, the porous carbon is microporous carbon. The pore size of the microporous carbon can be greater than 0.7 nm to about 2 nm. In other embodiments, the pore size is greater than 0.7 nm to about 1.5 nm, greater than 0.7 nm to about 1.2 nm, greater than 0.8 nm to about 2 nm, greater than 0.8 nm to about 1.5 nm, or greater than 0.8 nm to about 1.2 nm.

[0113] In some embodiments, the mass ratio of porous carbon to rylene dye is from about 1:1 to about 1:4. The mass ratio of porous carbon to rylene dye can be calculated based on the pore volume of porous carbon and the density of rylene dye. For example, for 1.391 cm 3 g -1 The mass ratio of AC (host) to PTCDA (filler) is about 1:2.36. In other embodiments, the mass ratio is about 1:1 to about 1.3, about 1:1 to about 1.25, about 1:15 to about 1.25, or about 1:2. The mass ratio of rylene dye to porous carbon can alternatively be referred to as filler / host ratio.

[0114] In some embodiments, the mixture is mechanically blended. This can be done by stirring the mixture or by subjecting the mixture to shear forces. In other embodiments, the mixture is uniformly blended.

[0115] In a subsequent step, the mixture is heated. Advantageously, the heating step under an inert atmosphere causes the rylene dye to become molten and thus diffuse into the pores of the porous carbon. The heating step changes the physical and optional chemical properties of the rylene dye, making it more processable. To this end, the heating step involves heating the rylene dye at a temperature above its recrystallization temperature, maintaining it at a suitable temperature for an appropriate amount of time, and then optionally cooling it. The heating step can also be an annealing step.

[0116] In some embodiments, the mixture is heated from about 300° C. to about 600° C. In other embodiments, the mixture is heated from about 300° C. to about 550° C., from about 300° C. to about 500° C., from about 300° C. to about 450° C., or from about 300° C. to about 400° C. In other embodiments, the mixture is heated to about 450° C.

[0117] In some embodiments, the inert atmosphere is argon. The inert atmosphere does not contain oxygen.

[0118] In some embodiments, the heating step is performed for about 2 hours to about 10 hours. In other embodiments, the heating step is performed for about 2 hours to about 9 hours, about 2 hours to about 8 hours, about 2 hours to about 7 hours, about 2 hours to about 6 hours, about 2 hours to about 5 hours, about 2 hours to about 4 hours, or about 2 hours to about 3 hours.

[0119] The method then involves at least partially carbonizing the mixture at a temperature of about 700° C. to about 1300° C. Since rylene dyes have a thermal decomposition temperature of about 550° C. to 600° C. under TGA, the amount of carbonization of the rylene dye can be controlled by holding the temperature and holding period. In other embodiments, the temperature is about 750° C. to about 1300° C., about 800° C. to about 1300° C., about 850° C. to about 1300° C., about 900° C. to about 1300° C., about 1000° C. to about 1300° C., about 1100° C. to about 1300° C., about 700° C. to about 1200° C., about 750° C. to about 1200° C., about 800° C. to about 1200° C., about 850° C. to about 1200° C., about 900° C. to about 1200° C., about 1000° C. to about 1200° C., or about 1100° C. to about 1200° C.

[0120] Carbonization is the conversion of organic matter into carbon by destructive distillation. Destructive distillation is a chemical process in which organic matter is decomposed by heating it to high temperatures; the term is generally applied to processing organic materials in the absence of air or in the presence of limited amounts of oxygen or other reagents (catalysts or solvents, such as steam or phenols). Carbonization is a pyrolysis reaction and is therefore considered a complex process in which many reactions occur simultaneously, such as dehydrogenation, condensation, hydrogen transfer, and isomerization. The amount of heat applied controls the degree of carbonization and the residual content of foreign elements. In particular, 1 g of PTCDA provides approximately 0.4 g of carbon during carbonization.

[0121] Advantageously, the pores blocked by the rylene dye are then carbonized within the porous carbon to convert the open pores into closed pores. This method alters the pore size of the porous carbon without completely blocking the pores and also consumes less energy than high-temperature annealing. Anodes for sodium ion storage formed using this method exhibit increased plateau capacity, improved cycling stability, satisfactory rate performance, and high areal capacity.

[0122] In some embodiments, the carbonization step is performed for at least 3 hours. In other embodiments, the step is performed for at least 4 hours, 5 hours, 6 hours, 8 hours, 10 hours, or 12 hours.

[0123] In some embodiments, the carbonization step is performed at a rate of about 3°C / minute to about 10°C / minute. In other embodiments, the step is performed at a rate of about 3°C / minute to about 9°C / minute, about 3°C / minute to about 8°C / minute, about 3°C / minute to about 7°C / minute, about 3°C / minute to about 6°C / minute, or about 4°C / minute to about 6°C / minute.

[0124] In some embodiments, at least 40% of the rylene dye is retained in and / or on the porous carbon and is partially carbonized. In this regard, at least 40% of the rylene dye is partially carbonized, while the remainder is removed by evaporation. The remainder of the rylene dye can be removed by a stream of inert gas in an inert atmosphere. In other embodiments, the rylene dye is carbonized by at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%.

[0125] In some embodiments, the carbonization step is performed under an inert atmosphere. In other embodiments, the inert atmosphere is argon. The inert atmosphere does not contain oxygen.

[0126] By adopting at least these steps, the pore size and pore width or diameter of the pores of the porous carbon can be adjusted to make it suitable for use as an electrode material and in a battery. In addition, depending on the type of porous carbon used, the skeleton density and therefore the density of the pores present in the carbon can be changed.

[0127] In some embodiments, a method of making a modified porous carbon composite material comprises:

[0128] a) mixing porous carbon and rylene dye to form a mixture;

[0129] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0130] c) carbonizing the mixture at a temperature of about 700° C. to about 1300° C. to form ultrafine pores in the porous carbon;

[0131] wherein the pore size of the ultramicropores (based on CO2 adsorption) is from about 0.2 nm to about 0.8 nm, and

[0132] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0133] In some embodiments, a method of making a modified porous carbon composite material comprises:

[0134] a) mixing porous carbon and rylene dye to form a mixture;

[0135] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0136] c) carbonizing the mixture at a temperature of about 700° C. to about 1300° C. to form ultrafine pores in the porous carbon;

[0137] The pore size of the ultramicropores (based on CO2 adsorption) is about 0.2 nm to about 0.8 nm.

[0138] The BET(N2) specific surface area of ​​the composite material is about 5m 2 g -1 About 80m 2 g -1 ,as well as

[0139] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0140] In some embodiments, a method of making a modified porous carbon composite material comprises:

[0141] a) mixing porous carbon and rylene dye to form a mixture;

[0142] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0143] c) carbonizing the mixture at a temperature of about 700° C. to about 1300° C. to form ultrafine pores in the porous carbon;

[0144] The pore size of the ultramicropores (based on CO2 adsorption) is about 0.2 nm to about 0.8 nm.

[0145] The BET(N2) specific surface area of ​​the composite material is about 5m 2 g -1About 80m 2 g -1 ,

[0146] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 ;as well as

[0147] The ratio of the BET (CO2) specific surface area to the BET (N2) specific surface area of ​​the composite material is from about 0.1 to about 50.

[0148] In some embodiments, a method of making a modified porous carbon composite material comprises:

[0149] a) mixing porous carbon with PTCDA to form a mixture;

[0150] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0151] c) carbonizing the mixture at a temperature of about 700° C. to about 1300° C. to form ultrafine pores in the porous carbon.

[0152] In some embodiments, a method of making a composite material comprises:

[0153] a) mixing porous carbon with PTCDA to form a mixture;

[0154] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0155] c) carbonizing the mixture at a temperature of about 700° C. to about 1300° C. to form ultrafine pores in the porous carbon;

[0156] wherein the pore size of the ultramicropores (based on CO2 adsorption) is from about 0.2 nm to about 0.8 nm, and

[0157] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0158] In some embodiments, a method of making a modified porous carbon composite material comprises:

[0159] a) mixing porous carbon with PTCDA to form a mixture;

[0160] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0161] c) carbonizing the mixture at a temperature of about 700° C. to about 1300° C. to form ultrafine pores in the porous carbon;

[0162] The pore size of the ultramicropores (based on CO2 adsorption) is about 0.2 nm to about 0.8 nm.

[0163] The BET(N2) specific surface area of ​​the composite material is about 5m 2 g -1 About 80m 2 g -1 ,as well as

[0164] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0165] In some embodiments, a method of making a modified porous carbon composite material comprises:

[0166] a) mixing porous carbon with PTCDA to form a mixture;

[0167] b) heating the mixture from about 300° C. to about 600° C. under an inert atmosphere; and

[0168] c) carbonizing the mixture at a temperature of about 700° C. to about 1300° C. to form ultrafine pores in the porous carbon;

[0169] The pore size of the ultramicropores (based on CO2 adsorption) is about 0.2 nm to about 0.8 nm.

[0170] The BET(N2) specific surface area of ​​the composite material is about 5m 2 g -1 About 80m 2 g -1 ,

[0171] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 ;as well as

[0172] The ratio of the BET (CO2) specific surface area to the BET (N2) specific surface area of ​​the composite material is from about 0.1 to about 50.

[0173] The present invention also discloses a modified porous carbon composite material, wherein the modified porous carbon composite material comprises:

[0174] a) porous carbon; and

[0175] b) an at least partially carbonized rylene dye;

[0176] The at least partially carbonized rylene dye covers the pores and the outer surface of the porous carbon.

[0177] The present invention also discloses a modified porous carbon composite material, wherein the modified porous carbon composite material comprises:

[0178] a) porous carbon structure; and

[0179] b) carbonized rylene dyes;

[0180] The carbonized rylene dye at least covers the inner pores of the porous carbon structure.

[0181] In some embodiments, the modified porous carbon composite material comprises:

[0182] a) porous carbon structure; and

[0183] b) carbonized rylene dyes;

[0184] The carbonized rylene dye at least covers the inner pores of the porous carbon structure.

[0185] The term "porous carbon structure" is used to refer to the skeletal carbon structure of a composite material. This is different from "porous carbon," which refers to the porous carbon used as a raw material for making a composite material. Therefore, "porous carbon" forms a composite material having a "porous carbon structure" when processed.

[0186] The carbonized rylene dye covers at least the inner pores of the porous carbon structure and can cover both the inner pores and the outer surface of the porous carbon structure. The carbonized rylene dye covers at least the inner pores, thereby reducing the pore size and pore diameter. When covering the outer surface, a negligible increase in the composite material particle size is observed.

[0187] In some embodiments, the mass ratio of the porous carbon structure to the at least partially carbonized rylene dye is from about 1:1 to about 1:4. In other embodiments, the mass ratio is from about 1:1 to about 1:3.5, from about 1:1 to about 1:3, from about 1:1 to about 1:2.5, from about 1:1 to about 1:2, or from about 1:1 to about 1:1.5.

[0188] In some embodiments, the at least partially carbonized rylene dye is at least 40% carbonized. In this regard, at least 40% of the rylene dye in / on the porous carbon is thermally decomposed into carbon. Since rylene dye has a thermal decomposition temperature of approximately 550°C to 600°C under TGA, the amount of carbonization of the rylene dye can be controlled by the holding temperature and holding period. In other embodiments, the carbonization is at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95%. In some embodiments, the rylene dye is completely carbonized.

[0189] The at least partially carbonized rylene dye coating the pores of the porous carbon structure reduces its pore size (pore diameter). In this regard, the mesoporous carbon is formed into microporous carbon when coated with the at least partially carbonized rylene dye. Similarly, the microporous carbon is formed into ultramicroporous carbon when coated with the carbonized rylene dye.

[0190] The carbonized rylene dye covers the pores of the porous carbon structure, reducing the pore size thereof. This is the result of the rylene dye covering the pores, which forms a carbonized layer at the pore size after carbonization and thereby narrows the pore size.

[0191] In some embodiments, the XRD pattern of the composite material shows the presence of a (002) peak derived from carbonized rylene dye and a (002) peak of porous carbon. In some embodiments, the (002) peak of carbonized rylene dye is about 25.2°. In some embodiments, the (002) peak of porous carbon is about 21.2°.

[0192] In some embodiments, the composite material has a BET(N2) specific surface area of ​​about 5 m 2 g -1 About 80m 2 g -1 In other embodiments, the BET(N2) specific surface area is about 5 m 2 g -1 About 75m 2 g -1 , about 5m 2 g -1 About 70m 2 g -1 , about 5m 2 g -1 About 65m 2 g -1 , about 5m 2 g -1 About 60m 2 g -1 , about 5m 2 g -1 to about 55m2 g -1 , about 5m 2 g -1 About 50m 2 g -1 , about 5m 2 g -1 About 45m 2 g -1 , about 5m 2 g -1 About 40m 2 g -1 , about 10m 2 g -1 About 40m 2 g -1 , or about 20m 2 g -1 About 40m 2 g -1 .

[0193] In some embodiments, the micropore (N2) specific surface area of ​​the composite material is about 5 m 2 g -1 About 80m 2 g -1 In other embodiments, the micropore (N2) has a specific surface area of ​​about 5 m 2 g -1 About 75m 2 g -1 , about 5m 2 g -1 About 70m 2 g -1 , about 5m 2 g -1 About 65m 2 g -1 , about 5m 2 g -1 About 60m 2 g -1 , about 5m 2 g -1 to about 55m 2 g -1 , about 5m 2 g -1 About 50m 2 g -1 , about 5m 2 g -1 About 45m 2 g -1 , about 5m 2 g -1 About 40m 2 g-1 , about 10m 2 g -1 About 40m 2 g -1 , or about 20m 2 g -1 About 40m 2 g -1 .

[0194] In some embodiments, the external (N2) specific surface area of ​​the composite material is about 0.5 m 2 g -1 About 30m 2 g -1 In other embodiments, the external (N2) surface area is about 1 m 2 g -1 About 30m 2 g -1 , about 5m 2 g -1 About 30m 2 g -1 , about 10m 2 g -1 About 30m 2 g -1 , about 15m 2 g -1 About 30m 2 g -1 , about 15m 2 g -1 About 25m 2 g -1 , or about 15m 2 g -1 About 20m 2 g -1 .

[0195] In some embodiments, the micropore volume of the composite material (based on N2 adsorption) is about 0.002 cm 3 g -1 to about 0.030cm 3 g -1 In other embodiments, the micropore volume is about 0.002 cm 3 g -1 to about 0.025cm 3 g -1 , about 0.002cm 3 g -1 to about 0.020cm 3 g -1 , about 0.002cm 3 g-1 to about 0.015cm 3 g -1 , or about 0.010cm 3 g -1 to about 0.015cm 3 g -1 .

[0196] In some embodiments, the external volume of the composite material (based on N2 adsorption) is about 0.005 cm 3 g -1 to about 0.1cm 3 g -1 In other embodiments, the outer volume is about 0.005 cm 3 g -1 to about 0.090cm 3 g -1 , about 0.005cm 3 g -1 to about 0.080cm 3 g -1 , about 0.005cm 3 g -1 to about 0.070cm 3 g -1 , about 0.005cm 3 g -1 to about 0.060cm 3 g -1 , about 0.010cm 3 g -1 to about 0.060cm 3 g -1 , about 0.020cm 3 g -1 to about 0.060cm 3 g -1 , about 0.030cm 3 g -1 to about 0.060cm 3 g -1 , or about 0.040cm 3 g -1 to about 0.060cm 3 g -1 .

[0197] In some embodiments, the total volume of the composite material (based on N2 adsorption) is about 0.01 cm 3 g -1 to about 0.13cm 3 g -1In other embodiments, the total volume is about 0.01 cm 3 g -1 to about 0.12cm 3 g -1 , about 0.01cm 3 g -1 to about 0.11cm 3 g -1 , about 0.01cm 3 g -1 to about 0.10cm 3 g -1 , about 0.01cm 3 g -1 to about 0.09cm 3 g -1 , about 0.01cm 3 g -1 to about 0.08cm 3 g -1 , about 0.01cm 3 g -1 to about 0.07cm 3 g -1 , about 0.02cm 3 g -1 to about 0.07cm 3 g -1 , about 0.03cm 3 g -1 to about 0.07cm 3 g -1 , about 0.04cm 3 g -1 to about 0.07cm 3 g -1 , or about 0.05cm 3 g -1 to about 0.07cm 3 g -1 .

[0198] In some embodiments, the composite material has a BET(CO2) specific surface area of ​​about 10 m 2 g -1 About 220m 2 g -1 In other embodiments, the BET(CO2) specific surface area is about 20 m 2 g -1 About 220m 2 g -1 , about 30m 2 g -1 About 220m 2 g-1 , about 40m 2 g -1 About 220m 2 g -1 , about 50m 2 g -1 About 220m 2 g -1 , about 60m 2 g -1 About 220m 2 g -1 , about 70m 2 g -1 About 220m 2 g -1 , about 80m 2 g -1 About 220m 2 g -1 , about 90m 2 g -1 About 220m 2 g -1 , about 90m 2 g -1 to about 210m 2 g -1 , about 90m 2 g -1 About 200m 2 g -1 , about 90m 2 g -1 About 190m 2 g -1 , about 90m 2 g -1 About 180m 2 g -1 , about 90m 2 g -1 About 170m 2 g -1 , or about 90m 2 g -1 About 160m 2 g -1 .

[0199] In some embodiments, the total volume of the composite material (based on CO2 adsorption) is about 0.08 cm 3 g -1 to about 0.4cm 3 g -1 In other embodiments, the total volume is about 0.08 cm 3 g -1 to about 0.39cm3 g -1 , about 0.08cm 3 g -1 to about 0.38cm 3 g -1 , about 0.08cm 3 g -1 to about 0.37cm 3 g -1 , about 0.08cm 3 g -1 to about 0.36cm 3 g -1 , about 0.08cm 3 g -1 to about 0.35cm 3 g -1 , about 0.08cm 3 g -1 to about 0.3cm 3 g -1 , about 0.08cm 3 g -1 to about 0.25cm 3 g -1 , about 0.08cm 3 g -1 to about 0.2cm 3 g -1 , or about 0.08cm 3 g -1 to about 0.15cm 3 g -1 .

[0200] In some embodiments, the ratio of the BET (CO2) specific surface area to the BET (N2) specific surface area of ​​the composite material is from about 0.1 to about 50. Since N2 and CO2 have different molecular sizes, this ratio can be quantified as the ratio of the pore size of less than 0.5 nm to the pore size of greater than 0.5 nm within the porous carbon. In other embodiments, the ratio is from about 0.2 to about 50, from about 0.5 to about 50, from about 1 to about 50, from about 5 to about 50, from about 10 to about 50, from about 15 to about 50, from about 20 to about 50, or from about 30 to about 50.

[0201] In some embodiments, the composite material comprises ultramicropores having a pore size (based on CO adsorption) of about 0.2 nm to about 0.8 nm. In other embodiments, the pore size is about 0.2 nm to about 0.7 nm, about 0.2 nm to about 0.6 nm, about 0.2 nm to about 0.5 nm, or about 0.3 nm to about 0.5 nm.

[0202] Graphitization is the process of heating amorphous carbon for an extended period of time so that the atomic structure is rearranged, thereby achieving an ordered crystalline structure. During graphitization, carbon atoms are rearranged to fill atomic vacancies and improve atomic layout. The degree of graphitization depends on the structure (graphitizable) of the carbon material and the graphitization temperature applied. The degree of graphitization can be determined by x-ray measurement. In some embodiments, the R value of the composite material is about 2 to about 5. In other embodiments, the R value is about 2.5 to about 5, about 3 to about 5, about 3.5 to about 5, or about 4 to about 5.

[0203] The skeletal density or true density of the composite material is the density of the composite material itself, excluding any voids or spaces between or on the surfaces of the carbon particles. In some embodiments, the skeletal density of the composite material is about 1.8 g cm -3 to about 2.5 g cm -3 In other embodiments, the skeletal density is about 1.8 g cm -3 to about 2.4 g cm -3 , about 1.8 g cm -3 to about 2.3 g cm -3 , about 1.8 g cm -3 to about 2.2 g cm -3 , about 1.9 g cm -3 to about 2.2 g cm -3 , about 2.0 g cm -3 to about 2.2gcm -3 , or about 2.1 g cm -3 to about 2.2 g cm -3 .

[0204] In some embodiments, the thickness of the carbonized rylene dye is from about 0.2 nm to about 1.2 nm. In other embodiments, the thickness is from about 0.2 nm to about 1.0 nm, from about 0.2 nm to about 0.9 nm, from about 0.2 nm to about 0.8 nm, from about 0.2 nm to about 0.7 nm, from about 0.2 nm to about 0.6 nm, from about 0.2 nm to about 0.5 nm, or from about 0.2 nm to about 0.4 nm. This can be quantified by measuring the pore size before and after carbonization, or by BET results.

[0205] In some embodiments, the modified porous carbon composite material comprises:

[0206] a) porous carbon structure; and

[0207] b) carbonized rylene dyes;

[0208] wherein the carbonized rylene dye at least covers the inner pores of the porous carbon structure;

[0209] wherein the composite material comprises ultramicropores, the pore size of the ultramicropores (based on CO2 adsorption) being from about 0.2 nm to about 0.8 nm; and

[0210] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0211] In some embodiments, the modified porous carbon composite material comprises:

[0212] a) porous carbon structure; and

[0213] b) carbonized rylene dyes;

[0214] wherein the carbonized rylene dye at least covers the inner pores of the porous carbon structure;

[0215] wherein the composite material comprises ultramicropores, the pore size of the ultramicropores (based on CO2 adsorption) being from about 0.2 nm to about 0.8 nm;

[0216] The BET(N2) specific surface area of ​​the composite material is about 5m 2 g -1 About 80m 2 g -1 ;as well as

[0217] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0218] In some embodiments, the modified porous carbon composite material comprises:

[0219] a) porous carbon structure; and

[0220] b) carbonized PTCDA;

[0221] wherein the carbonized PTCDA at least covers the inner pores of the porous carbon structure;

[0222] wherein the composite material comprises ultramicropores, the pore size of the ultramicropores (based on CO2 adsorption) being from about 0.2 nm to about 0.8 nm; and

[0223] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0224] In some embodiments, the modified porous carbon composite material comprises:

[0225] a) porous carbon structure; and

[0226] b) carbonized PTCDA;

[0227] wherein the carbonized PTCDA at least covers the inner pores of the porous carbon structure;

[0228] wherein the composite material comprises ultramicropores, the pore size of the ultramicropores (based on CO2 adsorption) being from about 0.2 nm to about 0.8 nm;

[0229] The BET(N2) specific surface area of ​​the composite material is about 5m 2 g -1 About 80m 2 g -1 ;as well as

[0230] The BET (CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 .

[0231] In some embodiments, the composite material comprises a porous carbon structure having ultramicropores, wherein the pore size of the ultramicropores (based on CO2 adsorption) is from about 0.2 nm to about 0.8 nm, wherein the composite material has a BET (N2) specific surface area of ​​about 5 m 2 g -1 About 80m 2 g -1 , and wherein the BET(CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 In some embodiments, the composite material comprises a porous carbon structure having ultramicropores, wherein the pore size of the ultramicropores (based on CO2 adsorption) is from about 0.2 nm to about 0.8 nm, wherein the BET (N2) specific surface area of ​​the composite material is about 5 m 2 g -1 About 80m 2 g -1 , and wherein the BET(CO2) specific surface area of ​​the composite material is about 10m 2 g -1 About 220m 2 g -1 , where the skeleton density of the composite material is about 1.8 g cm -3 to about 2.5 g cm -3 .

[0232] In some embodiments, the composite material comprises a porous carbon structure having ultramicropores, wherein the pore size of the ultramicropores (based on CO2 adsorption) is from about 0.2 nm to about 0.8 nm, wherein the ratio of the BET (CO2) specific surface area to the BET (N2) specific surface area of ​​the composite material is from about 0.1 to about 50. In some embodiments, the composite material comprises a porous carbon structure having ultramicropores, wherein the pore size of the ultramicropores (based on CO2 adsorption) is from about 0.2 nm to about 0.8 nm, wherein the ratio of the BET (CO2) specific surface area to the BET (N2) specific surface area of ​​the composite material is from about 0.1 to about 50, wherein the skeletal density of the composite material is about 1.8 g cm -3 to about 2.5gcm -3 .

[0233] The present invention also discloses a method for manufacturing an electrode, the method comprising:

[0234] a) mixing a composite material as disclosed herein with a binder solution to form a slurry;

[0235] b) applying the slurry to the surface of the electrical conductor; and

[0236] c) drying the slurry.

[0237] In some embodiments, the weight ratio of the composite material to the binder solution is from about 80:20 to about 95:5. In other embodiments, the weight ratio is from about 85:15 to about 95:5, or from about 90:10 to about 95:5.

[0238] In some embodiments, the concentration of the binder solution is from about 10 mg / mL to about 20 mg / mL. In some embodiments, the concentration is from about 10 mg / mL to about 18 mg / mL, from about 10 mg / mL to about 16 mg / mL, from about 10 mg / mL to about 14 mg / mL, or from about 12 mg / mL to about 14 mg / mL.

[0239] In some embodiments, the binder solution comprises a binder selected from sodium carboxymethylcellulose and / or polyvinylidene fluoride (PVDF).

[0240] In some embodiments, the drying step is performed at about 40° C. to about 80° C. In other embodiments, the temperature is about 50° C. to about 80° C., about 60° C. to about 80° C., or about 70° C. to about 80° C.

[0241] In some embodiments, the drying step is performed for about 2 hours to about 6 hours. In other embodiments, the time is about 3 hours to about 6 hours, about 4 hours to about 6 hours, or about 5 hours to about 6 hours.

[0242] In some embodiments, the drying step further comprises vacuum drying the slurry at about 100° C. to about 140° C. for at least 8 hours. In other embodiments, the temperature is about 110° C. to about 140° C., about 120° C. to about 140° C., or about 130° C. to about 140° C.

[0243] The electrical conductor may be a current collector that carries electrical charges that may form at the interfaces of and within the pores of the composite material to an electrical component configured to receive the charges.

[0244] In some embodiments, a method of making an electrode comprises:

[0245] a) mixing a composite material as disclosed herein with a binder solution to form a slurry;

[0246] b) applying the slurry onto the surface of the current collector; and

[0247] c) drying the slurry.

[0248] The present invention also discloses an electrode, which comprises:

[0249] a) a composite material as disclosed herein;

[0250] b) a binder; and

[0251] c) electrical conductors;

[0252] wherein the composite material and the binder are uniformly combined; and

[0253] The composite material and the adhesive cover at least one surface of the conductor.

[0254] In some embodiments, the electrode comprises:

[0255] a) a composite material as disclosed herein;

[0256] b) a binder; and

[0257] c) current collector;

[0258] wherein the composite material and the binder are uniformly combined; and

[0259] The composite material and the binder cover at least one surface of the current collector.

[0260] In some embodiments, the composite material and the adhesive cover at least two surfaces of the electrical conductor. In other embodiments, the composite material and the adhesive completely cover the electrical conductor.

[0261] In some embodiments, the weight ratio of composite material to binder is from about 80:20 to about 95:5. In other embodiments, the weight ratio is from about 85:15 to about 95:5, or from about 90:10 to about 95:5.

[0262] In some embodiments, the mass loading of the composite material and binder on the conductor is at least 15 mg cm -2 In other embodiments, the mass loading of the composite material and binder on the conductor is at least 16 mg cm -2 , at least 17 mg cm -2 , at least 18 mg cm -2 , at least 19 mg cm -2 , or at least 20 mg cm -2 .

[0263] In some embodiments, the electrode is at about 2000 mA g -1 The capacity at a current density of more than 100 mAh g -1 The capacity may be reversible. In other embodiments, the capacity is greater than 110 mAh g -1 , greater than 120mAh g -1 , greater than 130mAh g -1 , greater than 140mAh g -1 , or greater than 150mAh g -1 In other embodiments, the electrode is at about 2000 mAg -1 The capacity at a current density of about 100 mAh g -1 to about 200mAh g -1 .

[0264] In some embodiments, the electrode is at about 30 mA g -1 The capacity at a current density of more than 300 mAh g -1 The capacity may be reversible. In other embodiments, the capacity is greater than 310 mAh g -1 , greater than 320mAh g -1 , greater than 330mAhg -1 , greater than 340mAh g -1 , or greater than 350mAh g -1 In other embodiments, the electrode is at about 30 mA g -1 The capacity at a current density of about 300 mAh g -1 to about 400mAh g -1 .

[0265] In some embodiments, the electrode retains at least 80% of its initial capacity after 200 cycles. Cycling performance can be in the range of about 50 mAh g -1 In other embodiments, the electrode retains at least 85%, at least 90%, or at least 95% of its initial capacity after 200 cycles.

[0266] In some embodiments, the electrode is at about 0.1 mA cm -2 The areal capacity at a current density of about 6 mAh cm -2 to about 8 mAh cm -2 In other embodiments, the areal capacity is about 6 mAh cm -2 to about 7.5 mAh cm -2 , or about 6 mAh cm -2 to about 7 mAh cm -2 .

[0267] In some embodiments, the electrode is at about 0.5 mA cm -2 The areal capacity at a current density of about 3 mAh cm -2 to about 5 mAh cm -2 In other embodiments, the areal capacity is about 3 mAh cm -2 to about 4.5 mAh cm -2 , or about 3 mAh cm -2 to about 3 mAh cm -2 .

[0268] In some embodiments, at least 80% of the areal capacity is retained at temperatures between about -20° C. and about 40° C. In other embodiments, the areal capacity is retained at least 85%, at least 90%, or at least 95%.

[0269] In some embodiments, the electrode has an areal capacity of about 5.3 mAh cm at about -20°C. -2 .

[0270] In some embodiments, when in the presence of an electrolyte during the discharge and / or charge process, the electrode can undergo a capacitive adsorption process and a diffusion-controlled process. In some embodiments, the cations of the electrolyte can be adsorbed onto the surface of the electrode. In other embodiments, the cations of the electrolyte can be inserted into the ultramicropores of the electrode. In other embodiments, the cations of the electrolyte are not embedded in the ultramicropores. Embedding expands the van der Waals gap between the sheets, which requires energy. Typically, this energy is supplied by charge transfer between the guest and the host solid. In this regard, there is no charge transfer between the cations and the ultramicropores, but the cations gather together to improve stability. In some embodiments, after the cations are incorporated into the ultramicropores, the XRD (002) peak does not shift.

[0271] The present invention also discloses a battery, comprising:

[0272] a) organic cathode;

[0273] b) an anode comprising a composite material as disclosed herein; and

[0274] c) Sodium metal applied to at least one surface of the anode.

[0275] In some embodiments, the anode comprises an electrode as disclosed herein.

[0276] In some embodiments, the battery can exhibit a low voltage plateau region and a high voltage slope region at different capacities.

[0277] In some embodiments, the organic cathode comprises a rylene dye.

[0278] In some embodiments, the mass loading ratio of the organic cathode to the anode is from about 1:2 to about 1:3.

[0279] In some embodiments, the N / P ratio (areal capacity ratio of the negative electrode to the positive electrode) is from about 1.1:1 to about 1.2:1.

[0280] Coulombic efficiency is the ratio of the total charge extracted from the battery to the total charge entering the battery within a full cycle. A high initial coulombic efficiency is desirable because it implies an effective interface structure and little electrolyte consumption, indicating that the battery's life and power output are improved. In some embodiments, the initial coulombic efficiency of the battery is from about 70% to about 90%. In other embodiments, the initial coulombic efficiency is from about 75% to about 90%, from about 80% to about 90%, from about 85% to about 90%, or from about 90% to about 90%. The initial coulombic efficiency (ICE) can be calculated as follows:

[0281]

[0282] In some embodiments, during charging and / or discharging of the battery, the battery is characterized by 23 The peak at 4.44 ppm in NaMAS NMR indicates that Na + adsorbed on the surface sites of the composite material.

[0283] In some embodiments, when the battery is fully discharged, the battery is characterized by 23 The peaks from about -20 ppm to about -30 ppm in Na MAS NMR indicate the presence of Na in the ultramicropores of the composite. + In other embodiments, when the battery is fully discharged, the battery is characterized by 23 The peak at 4.44 ppm in Na MAS NMR indicates that Na + adsorbed on the surface sites of the composite material.

[0284] As disclosed herein, high-performance hard carbon anodes in sodium-ion batteries (SIBs) can be synthesized using a facile, cost-effective, and large-scale process using ultra-microporous (<0.5 nm)-dominated hard carbon composite material formed by a melt-diffusion-carbonization strategy ( FIG. 1A ). For example, microporous carbon and perylene tetracarboxylic dianhydride (PTCDA) can first be mechanically blended in a specific mass ratio and then annealed in argon at 400° C. for 3 hours. Above the melting point of PTCDA (approximately 350° C.), the molten PTCDA diffuses into the microporous carbon and is subsequently adsorbed on the inner surface of the micropores. During the further carbonization process, the PTCDA within the micropores is carbonized, while the residual PTCDA is evaporated and discharged with the argon flow. For consistency of measurements and to demonstrate the present invention, commercial activated carbon (AC) was first chosen as a model subject due to its enhanced porosity.

[0285] Scanning electron microscopy (SEM) images show that after the melt diffusion-carbonization process, the morphology of the micron-sized AC particles is well maintained without obvious residual PTCDA-derived carbon (Figure 1B, Figure 1C). Transmission electron microscopy (TEM) images of the exemplary composite material ACGC900 (using activated carbon and PTCDA as starting materials and carbonized at 900°C; relevant abbreviations can be found in the experimental section) show a disordered structure with no obvious porosity, which is different from the microporous structure of AC (Figure 1D). The selected area electron diffraction (SAED) pattern of the ACGC900 particles shows a certain degree of graphitization with obvious reflection rings corresponding to the (110) plane of the graphite structure, which can be attributed to the introduction of PTCDA-derived carbon inside the micropores (inset in Figure 1D). In addition, the Brunauer–Emmett–Teller (BET) specific surface area (S BET ) from 1429m 2 g -1 (For AC) significantly reduced to 48.4m 2 g -1 (For the designed ACGC900). Compared with AC, no micropores with a size of about 1.5 nm can be detected in ACGC900 ( Figure 1F ), indicating that most micropores are regulated to be inaccessible to N2. It is worth noting that, as Figure 1E and Figure 11 As shown in Figure 2, there is a clear hysteresis between the N2 adsorption / desorption isotherms of ACGC900, indicating the presence of confined pores or ultramicropores. Compared with N2 ) and higher operating temperature (273 K for CO2 compared to 77 K for N2), CO2 adsorption measurements are highly effective for detecting the possible presence of ultra-micropores (<0.5 nm). Figure 6 As can be seen from Table 2, the S of ACGC900 calculated from CO2 adsorption measurements BET About 196.6m 2 g -1 , than the S of ACGC900 calculated by N2 adsorption / desorption BET In addition, the pore size (or pore diameter) of ACGC900 is mainly distributed in the range of 0.3 nm to 0.5 nm, and the pore volume is about 0.365 cm 3 g -1 The above results demonstrate the existence of a large number of ultramicropores in ACGC900, which can reduce the interfacial contact between the inner surface of carbon and the electrolyte and thus minimize the side reactions.

[0286] Table 1. Specific surface area and volume of ACGCx calculated from N2 adsorption / desorption tests.

[0287]

[0288] [a] Micropore specific surface area determined by the t-method from the N2 adsorption branch at 77 K.

[0289] [b] External specific surface area determined by the t-method external surface area

[0290] [c] Micropore volume determined by the HK method from the N2 adsorption branch at 77 K

[0291] [d] External volume determined by the sum of the mesopore volume from the DFT method and the macropore volume calculated from the adsorption curve by the BJH method

[0292] [e] Total volume determined by the sum of micropores and external volume

[0293] Note: The specific surface area of ​​ACGCx calculated from N2 adsorption / desorption tests decreases with increasing carbonization temperature.

[0294] Table 2. Specific surface areas of ACGCx calculated from CO2 and N2 adsorption / desorption tests

[0295]

[0296] Note: Skeletal (true) density data were recorded on an AccuPyc II 1340 analyzer using helium as the analysis gas.

[0297] The microstructure of the rationally designed carbon was further investigated by X-ray diffraction (XRD) measurements ( Figure 1G ). Compared with the (002) peak of AC, the (002) peak of ACGC900 becomes broader and shifts to a higher degree. By applying the curve fitting method, the broad peak of ACGC900 can be divided into two parts. Specifically, the fitting peaks located at about 25.21° and 21.21° can be well matched with the (002) peaks of GC and AC, respectively ( Figure 1G The coexistence of two different carbon phases further proves the successful encapsulation, which is consistent with the SEM results (Figure 1B and Figure 1C). Figure 7 ) calculate the R value (an indicator of the degree of graphitization in the carbon material). Figure 1G As shown in the insert table, the R value of ACGC900 is higher than that of AC, indicating that the degree of graphitization of ACGC900 is higher, which is consistent with the Raman results ( Figure 8 Improved graphitization can enable good electrical conductivity, which promotes fast discharge / charge performance.

[0298] The electrochemical properties of AC, GC, and ACGC900 electrodes were explored by galvanostatic discharge / charge measurements. Figure 2 In A, the discharge / charge curves of AC and GC electrodes are all inclined curves, which is mainly due to the Na + Capacitive storage is caused on the surface sites. For the ACGC900 electrode, in addition to the slope region above 0.1 V, a platform also appears at about 0.1 V. Therefore, there is also a pair of redox peaks at about 0.1 V in the cyclic voltammetry (CV) curve ( Figure 2 B). Note that the tilted capacity of the ACGC900 electrode is almost equal to that of the AC electrode, and the capacity increase originating from the plateau region can be attributed to the additional storage sites from the ultramicropores. Figure 2 C and Figure 9 The cycling performance and rate performance of the three electrodes were compared. -1 When cycling, a sharp drop in capacity can be observed from the tenth cycle and almost no capacity can be obtained after 200 cycles. The rapid failure of the AC electrode can be attributed to the high accessible surface area and low conductivity, which may lead to an increase in the solid electrolyte interface (SEI) layer. Meanwhile, for the ACGC900 electrode, about 90% of the initial capacity can be retained after 200 cycles. The improved cycling stability can be attributed to the unique structure after encapsulation, including reduced interfacial contact between the electrode and the electrolyte and improved graphitization. In addition, the ACGC900 electrode can maintain a high initial capacity at 2000 mA g -1 Get more than 100mAh g -1 , while there is almost no capacity for the AC electrode, further demonstrating the advantage of the unique structure after melt diffusion-carbonization.

[0299] In order to further explore the relationship between microstructure and sodium ion storage performance, ACGCx (x = 750, 900, 1050 and 1200) samples were prepared at different carbonization temperatures. Figure 10 Furthermore, CO2 and N2 adsorption / desorption measurements were performed to explore the evolution of the pore structure in ACGCx ( Figures 11 to 12 As shown in Tables 1 and 2, the S BET In addition, as the temperature increases, the skeleton (true) density increases from 1.89 g cm -3 (ACGC750) increases monotonically to 2.14 g cm -3(ACGC1200), which was obtained by helium pycnometry. These temperature-dependent characteristics indicate that the ultramicropores in ACGCx increase with increasing temperature. Figure 3A shows the ACGCx electrode at 50 mA g -1 The discharge / charge curves in the voltage range of 0.001 V to 3 V are shown. The platform capacity increases with increasing temperature, indicating that the Na + The storage sites increased, which is consistent with the results from helium pycnometry tests and CO2 adsorption measurements. The tilt capacity contribution rate decreased linearly with the increase of the R value of ACGCx (Figure 3B, Figure 7 、 Figures 13 to 15 and Table 3), where lower R values ​​indicate lower graphitization or more defect sites. The decrease in tilted capacity with increasing temperature can be attributed to the reduced graphite interlayer spacing or defect sites. In addition, the initial coulombic efficiency (ICE) value increases with S from N2 adsorption / desorption measurements. BET decreases and increases linearly ( Figure 16 and Table 4), indicating that parasitic reactions with respect to the electrolyte are reduced. Overall, among all ACGCx electrodes, the ACGC1050 electrode shows the highest platform capacity and overall capacity as well as the best rate capability and cycling stability ( Figure 17 ). Therefore, the optimal temperature was determined to be 1050℃.

[0300] Table 3. Calculated R values ​​for various samples

[0301]

[0302] Table 4. Initial Coulombic Efficiency (ICE) values ​​of various samples

[0303]

[0304] In addition, the relationship between the porous structure of the porous carbon raw material (porous carbon host) and the electrochemical performance relative to the final composite product was studied at the optimal temperature ( Figures 18 to 20 and Table 5). For comparison, different S BET As shown in Figure 3C and Figure 21, among these carbon electrodes, the LCGC electrode provides the highest capacity and stable cycling performance (Figure 22). A quantitative relationship is established between the platform capacity and the mass ratio of filler / host, that is, the lower the filler / host ratio, the larger the platform capacity can be ensured (Figure 3D). Therefore, the porous carbon host with a micropore-dominated structure can enable a larger platform capacity to be achieved at an optimal temperature of 1050°C. In addition to the -1 346mAh g -1 In addition to the high reversible capacity, the LCGC electrode also exhibits satisfactory rate performance. Figure 3E As shown in the figure, at 2000mA g -1 It can still provide 125mAh g -1 The high reversible capacity of α-carbon anodes demonstrates superior performance to that of previously reported hard carbon anodes ( Figure 3F and Table 6).

[0305] Table 5. Specific surface area and volume calculated from N2 adsorption / desorption tests.

[0306]

[0307] [a] Micropore specific surface area determined by the t-method from the N2 adsorption branch at 77 K.

[0308] [b] External specific surface area determined by the t-method external surface area

[0309] [c] Micropore volume determined by the HK method from the N2 adsorption branch at 77 K

[0310] [d] External volume determined by the sum of the mesopore volume from the DFT method and the macropore volume calculated from the adsorption curve by the BJH method

[0311] [e] Total volume determined by the sum of micropores and external volume

[0312] From the above electrochemical results, it can be concluded that the introduction of ultramicropores is indeed the cause of the platform capacity. In order to prove the sodium ion storage mechanism, a further -1 to 1.0mV second -1 Scan rate dependent CV and galvanostatic intermittent titration technique (GITT) measurements (Figures 4A to 4C and Figures 23 to 25 During the discharge / charge process, there are both surface capacitive adsorption and diffusion-controlled processes for sodium ion storage. The contribution of the two mechanisms can be expressed by the power law formula: i = av b As shown in Figure 4B, the b-value of the high voltage slope region in the ACGC electrode is about 1.0, corresponding to the Na + However, the b-value of the low voltage plateau region in the ACGC electrode is about 0.5, indicating a diffusion-controlled process. Meanwhile, during the discharge / charge process, Na + Diffusion coefficient (D Na + ) as a function of potential shows a U turning point at about 0.05 V ( FIG4C ). D Na +The rapid decrease at about 0.05 V can be attributed to the Na + The large diffusion barrier inserted into the ultramicropores is consistent with the low b value in the low voltage plateau region (Figure 4B). Na + Corresponding to Na + Adsorption and aggregation inside the ultramicropores. In other words, Na + Adsorption on surface sites is considered to be capacitive behavior, and Na + Insertion into the ultramicropores is a diffusion process.

[0313] In situ XRD measurements are an effective and real-time technique for detecting possible changes in the interlayer spacing during the discharge / charge process. -2 The in-situ XRD pattern of the second discharge / charge cycle was used for analysis. As shown in Figure 4D, the band at 25.6° represents the (002) peak, indicating that about If there is intercalation, the (002) peak detected by the XRD pattern will undergo a peak shift during the discharge / charge process. However, from Figures 4D and 4E, no peak shift of the (002) peak or new peak can be observed during the entire process, proving that there is no intercalation / deintercalation into / from the graphene interlayer in both the tilted region and the platform region. In addition to the relationship between the tilted capacity and the R value (Figure 3B), the in situ XRD results further prove that the tilted capacity is determined by the Na + The adsorption / desorption to / from surface sites is also consistent with the high b-values ​​in the tilted region.

[0314] To further explore the sodium ion storage mechanism in the platform region, an ex situ 23 Na MAS NMR measurement. As can be seen in Figure 4F, two resonances at -6.87 ppm and 4.44 ppm can be observed in the spectra obtained from the electrodes discharged to 0.5 V and 0.2 V. Note that there is no washing process for the electrode, and the peak at -6.87 ppm can be attributed to the sodium salt in the electrolyte. With discharge, the peak at 4.44 ppm appears, indicating that Na + When the electrode is fully discharged to 0.001 V, a broad peak located in the region of -20 ppm to -30 ppm appears, indicating the presence of Na with more restricted mobility. + , such as in ultramicropores. When the electrode was recharged to 3 V, only the peak at -6.87 ppm remained and the other peaks disappeared accordingly, indicating that Na + Reversible storage on the surface and inside the ultramicropores. When the electrode is recharged to 0.1 V, the peak returns almost to the peak position of the electrode discharged to 0.1 V, proving the high reversibility of the pore filling process. Therefore, it is indeed Na+ Filling the ultra-micropores, then Na + The aggregation of ions leads to a low voltage platform at about 0.1 V. Therefore, the “adsorption / pore filling” mechanism in the sodiumization process can be demonstrated ( Figure 26 ).

[0315] For practical applications, advanced sodium ion storage performance at room temperature / low temperature in thick electrodes is also significant. Therefore, a high mass loading of about 19 mg cm was further fabricated. -2 As shown in Figure 5A, it is possible to -2 Achieved 6.14 mAh cm -2 After 41 cycles (about 7.5 months of cycling), almost no capacity degradation was observed, indicating that the cycling stability of this electrode is excellent even at high loads. -2 ) at a much higher current density (0.5 mA cm -2 ) can still maintain about 53.1% capacity (3.26mAh cm -2 ), indicating that the fabricated thick electrode has excellent rate performance (Figures 5B and Figure 27 ). As shown in Figure 5C, the low temperature performance of the thick LCGC electrode from -20°C to 40°C was further explored. Specifically, the capacity retention of the thick electrode was about 87%, 90%, 95%, 100% and 100% compared with the capacity obtained at 25°C (Figure 5D). In addition, Figure 28 The potential dependence of D Na + curves can be observed at different temperatures Na + The diffusion kinetics inside the thick electrode are similar, indicating satisfactory low-temperature performance. In addition, the electrochemical performance of the coin-type full cell was evaluated. The sodium-containing LGCG anode and the organic cathode (PTCDA) were assembled into a full cell with an N / P ratio (area capacity ratio of the negative electrode to the positive electrode) of 1.15:1. Figure 5E shows the full cell at 10 mA g -1 Approximately 97.1 mAh g can be obtained from the initial five discharge / charge cycles in the voltage range of 0.5 V to 3.0 V. -1 It should be noted that the current density and capacity are calculated from the total mass of the active material. When the current density increases to 90 mA g -1 When the capacity is maintained at a high rate of 65.5%, 63.6 mAh g -1 5F), indicating the excellent rate capability of the full-cell. In short, the excellent performance of thick electrodes and full-cells demonstrates the great potential of this carbon anode for commercial applications in SIBs.

[0316] In summary, a melt diffusion-carbonization strategy was developed to block the micropores of porous carbon into ultramicropores (0.3 nm to 0.5 nm). + The pores are accessible while the electrolyte is inaccessible, which can effectively minimize the decomposition of the electrolyte, and then lead to a high ICE value of about 87.9%. In addition, the optimized anode exhibits comprehensive excellent electrochemical performance (i.e., high reversible capacity, excellent cycling stability and satisfactory rate performance). With the help of a series of scan rate-dependent CV, GITT, in situ XRD and ex situ solid-state NMR, the "adsorption / pore filling" sodium ion storage mechanism can be reliably demonstrated. Notably, with 6.14 mAh cm -2 The high-areal capacity thick electrode exhibited ultrahigh cycling stability exceeding 7.5 months, satisfactory rate capability, and excellent low-temperature performance. Furthermore, a coin-type full cell based on a PTCDA cathode and a sodiated anode showed high reversible capacity and excellent rate capability. These findings reveal a promising strategy for designing practical carbon anode materials for SIBs with high energy density, high rate capability, and excellent low-temperature performance.

[0317] Table 6. Research on hard carbon anodes for SIBs

[0318]

[0319] Experimental part

[0320] Chemicals and Materials: Activated carbon (AC, XFP06) and cubic mesoporous carbon (CMK-8, XFP02) were purchased from Jiangsu XFNANO Materials Tech Co., Ltd. Perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and potassium hydroxide (KOH, AR, pellets, ≥85%) were obtained from SIGMA-ALDRICH PTE LTD. All chemicals used throughout this work were used as received without any further purification.

[0321] Synthesis of GC: Dried PTCDA was heated to 900°C in argon at a rate of 5°C / min and then held for 5 hours. The furnace was then cooled to room temperature at a rate of 5°C / min. The obtained product was designated as GC.

[0322] Synthesis of ACGCx: AC and PTCDA were dried under vacuum at 110 °C overnight before use. First, the dried AC and PTCDA were mechanically mixed. The mass ratio of AC to PTCDA was calculated based on the pore volume of AC and the density of PTCDA (e.g., for 1.391 cm 3 / g of AC pore volume, with a mass ratio of AC to PTCDA of approximately 1:2.36). PTCDA was then encapsulated into AC via a melt diffusion-carbonization method in argon at 400°C for 3 hours, followed by further carbonization at a specific temperature at a rate of 5°C / minute for an additional 5 hours. The furnace was then cooled to room temperature at a rate of 5°C / minute. The products obtained by carbonization at different temperatures (i.e., 750°C, 900°C, 1050°C, and 1200°C) are denoted as ACGCx (x = 750, 900, 1050, and 1200).

[0323] Synthesis of ACGC, CMK8GC, HCGC and LCGC: For the hydrothermal reaction, a solution (40 mL) containing 6.4 g of sugar was filled into an autoclave (50 mL) and then heated at 180°C for 8 hours to obtain a black powder. After drying, the obtained black powder (denoted as BP) was carbonized in Ar at 900°C at a rate of 3°C / min for 5 hours, which was denoted as LC (low specific surface area carbon). To synthesize HC (high specific surface area carbon), the dried BP was first carbonized in Ar at 500°C at a rate of 5°C / min for 2 hours. The obtained product was then physically mixed with KOH at a mass ratio of 1:4. The mixture was activated at 800°C at a rate of 5°C / min for 2 hours. The synthesis of ACGC, CMK8GC, HCGC and LCGC was similar to that of ACGC1050.

[0324] Characterization: The morphology and structure of the electrode materials were studied by SEM (JSM6700F) and TEM (JEOL-2010). XRD analysis was performed on a Bruker D8 Advance X-ray diffractometer. Raman spectra were collected at 514 nm (green) on a Horiba Jobin Yvon modular Raman spectrometer. Specific surface area, pore size distribution, and cumulative pore volume were calculated from N2 adsorption-desorption isotherms measured on a NOVA 2200e. CO2 adsorption tests were performed on an Autosorb-iQ. Data were recorded at a Larmor frequency of 105.8 MHz on a Bruker AdvanceIII 400 NMR spectrometer equipped with an 89 mm wide-bore 9.4 T superconducting magnet and a 1.3 mm HX probe. 23 Na Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) experiment. 23 For the Na NMR data, a single pulse was applied at a spinning speed of 80 kHz. 23Na chemical shifts were referenced to 1 M NaCl solution. True density was measured using an AccuPyc II 1340 analyzer using helium as the analytical gas.

[0325] Electrochemical measurements: CMCNa binder was first dissolved in DI water to form a uniform binder solution with a concentration of 12.5 mg / mL. The vacuum-dried active material was then added to the binder solution at a weight ratio of 90:10 (for active material and binder). The slurry was stirred overnight and then pasted onto copper foil, which was then dried at 50°C for 4 hours. Circular electrodes were obtained by punching, which were then vacuum-dried at 120°C overnight. The average mass loading of each electrode was approximately 1.5 mg cm -2 Up to 2.0 mg cm -2 Coin-type cells (2032) were assembled in an argon-filled glove box, where the concentrations of moisture and oxygen were kept below 0.2 ppm. Sodium metal was used as the anode. Whatman GF / B glass fiber was used as the separator, and the electrolyte was a 1 M solution of sodium trifluoromethanesulfonate (NaOTf) dissolved in diethylene glycol dimethyl ether (DEGDME). The ionization temperature was set at room temperature using a LAND-CT2001A multichannel galvanostat (Wuhan, China) in the range of 0.001 V to 3.0 V (vs. Na / Na + ) voltage range. -1 CV curves were obtained at a scan rate of 100 nm within a voltage window of 0.001 V to 3.0 V. Full cells were assembled using a sodium-containing LCGC anode and a PTCDA cathode in a weight ratio of 1:2.54. The full cells were cycled within a voltage window of 0.5 V to 3.0 V.

[0326] If the battery voltage is 1 / 2 The diffusion coefficient can be calculated from the GITT potential curve using Fick's second law as follows:

[0327]

[0328] The density of carbon is calculated according to the following equation:

[0329]

[0330] where ρ(g cm -3 ) is the density of carbon, V 总和 (cm 3 g -1 ) is the total pore volume measured by the N2 isotherm, ρ 碳 is the true density of carbon (2 g cm-3 ).

[0331] For the GITT test, the cells were discharged / charged at C / 10 with a current pulse duration of 0.5 h and an interval of 1 h.

[0332] It will be understood that numerous further modifications and permutations of the aspects of the described embodiments are possible. Accordingly, the described aspects are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims.

[0333] Throughout this specification and the appended claims, unless the context requires otherwise, the word "comprise" and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0334] Reference in this specification to any previous publication (or information derived therefrom) or any known matter is not and should not be taken as an acknowledgment or endorsement or any form of suggestion that the previous publication (or information derived therefrom) or known matter forms part of the common general knowledge in the field of endeavor to which this specification relates.

Claims

1. A modified porous carbon composite material comprising: a) porous carbon structure; and b) carbonized rylene dyes; wherein the carbonized rylene dye at least covers the inner pores of the porous carbon structure; The BET specific surface area of ​​the composite material based on CO2 adsorption is 10 m 2 g -1 Up to 220m 2 g -1 and / or the BET specific surface area of ​​the composite material based on N2 adsorption is 5m 2 g -1 Up to 80m 2 g -1 ;as well as The composite material comprises ultramicropores, and the pore size of the ultramicropores based on CO2 adsorption is 0.2 nm to 0.8 nm. 2 . The composite material according to claim 1 , wherein the mass ratio of the porous carbon structure to the at least partially carbonized rylene dye is 1:1 to 1:

4.

3. The composite material according to any one of claims 1 to 2, wherein the ratio of the BET specific surface area based on CO2 adsorption to the BET specific surface area based on N2 adsorption of the composite material is 0.1 to 50.

4. The composite material according to any one of claims 1 to 2, wherein an XRD pattern of the composite material shows the presence of a (002) peak derived from carbon of the carbonized rylene dye and a (002) peak of the porous carbon structure. The composite material according to claim 4 , wherein the (002) peak derived from carbon of the carbonized rylene dye is 25.2°. The composite material according to claim 4 , wherein the (002) peak of the porous carbon is 21.2°.

7. The composite material according to any one of claims 1 to 2, wherein the total volume of the composite material based on N2 adsorption is 0.01 cm 3 g -1 to 0.13cm 3 g -1 .

8. The composite material according to any one of claims 1 to 2, wherein the total volume of the composite material based on CO2 adsorption is 0.08 cm 3 g -1 to 0.4cm 3 g -1 .

9. The composite material according to any one of claims 1 to 2, wherein the composite material has a skeletal density of 1.8 g cm -3 Up to 2.5 g cm -3 .

10. A method for manufacturing an electrode, comprising: a) mixing the composite material according to any one of claims 1 to 9 with a binder solution to form a slurry; b) applying the slurry on the surface of a conductor; as well as c) drying the slurry. The method according to claim 10 , wherein the weight ratio of the composite material to the binder solution is 80:20 to 95:

5. 12 . The method according to claim 10 , wherein the concentration of the binder solution is 10 mg / mL to 20 mg / mL.

13. The method according to any one of claims 10 to 11, wherein the binder solution comprises a binder selected from sodium carboxymethylcellulose and / or polyvinylidene fluoride (PVDF).

14. The method according to any one of claims 10 to 11, wherein the drying step is performed at 40 to 80°C.

15. The method according to any one of claims 10 to 11, wherein the drying step is performed for 2 to 6 hours.

16. The method according to any one of claims 10 to 11, wherein the drying step further comprises vacuum drying the slurry at 100°C to 140°C for at least 8 hours.

17. An electrode comprising: a) A composite material according to any one of claims 1 to 9; b) a binder; and c) electrical conductors; wherein the composite material and the binder are uniformly combined; and The composite material and the adhesive cover at least one surface of the conductor.

18. The electrode according to claim 17, wherein the electrode has a -1 The current density is greater than 100 mAh g -1 Capacity or at 30mA g -1 The current density is greater than 300 mAh g -1 capacity.

19. An electrode according to claim 17 or 18, which retains at least 80% of its initial capacity after 200 cycles.

20. The electrode according to any one of claims 17 to 18, wherein the mass loading of the composite material and the binder on the electrical conductor is at least 15 mg cm -2 .

21. The electrode according to any one of claims 17 to 18, having a peak current of 0.1 mA cm -2 At a current density of 6 mAh cm -2 area capacity or at 0.5 mA cm -2 At a current density of 3 mAh cm -2 area capacity.

22. The electrode of any one of claims 17 to 18, wherein at least 80% of the areal capacity is retained at -20°C.

23. A battery comprising: a) organic cathode; b) an anode comprising the composite material according to any one of claims 1 to 9; as well as c) Sodium metal applied to at least one surface of the anode.

24. The battery of claim 23, wherein the organic cathode comprises a rylene dye. 25 . The battery according to claim 23 , wherein the mass loading ratio of the organic cathode to the anode is 1:2 to 1:

3.

26. The battery according to any one of claims 23 to 24, wherein the area capacity ratio of the negative electrode to the positive electrode is 1.1:1 to 1.2:

1.

27. The battery of any one of claims 23 to 24, wherein during charging and / or discharging of the battery, the battery is characterized by 23 The peak at 4.44 ppm in Na MAS NMR.

28. The battery of any one of claims 23 to 24, wherein when the battery is fully discharged, the battery is characterized by 23 A peak at 4.44 ppm and a peak at -20 ppm to -30 ppm in Na MAS NMR.

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