Samarium monatomic electrode material for supercapacitor and application thereof
By using a conductive carbon-based framework to load samarium single-atom active sites and nitrogen-containing coordination structures in supercapacitors, the problems of low utilization of rare earth components and easy structural instability were solved, achieving efficient charge storage and long-term cycling performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UESTC (SHENZHEN) ADVANCED RES INST
- Filing Date
- 2026-06-12
- Publication Date
- 2026-07-31
AI Technical Summary
In existing supercapacitors, rare earth components exist in the form of polycrystalline nanoparticles or bulk oxides, resulting in low dispersion of active sites, insufficient binding strength, and high charge transfer resistance, which limits the cycle life and high power output performance of electrode materials.
A conductive carbon-based framework is used to load samarium single-atom active sites and nitrogen-containing coordination structures. Spatial coordination units are formed through chemical bonding. The samarium single atoms are distributed in an atomically dispersed state to construct local polarization centers, which enhances the electrostatic attraction of the electrode material to ions and reduces electrochemical polarization.
It improves the charge exchange rate and structural stability of electrode materials in alkaline electrolytes, enhances high power output performance and long cycle life, and reduces electrochemical polarization and polarization loss.
Smart Images
Figure CN122494465A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrochemical energy storage materials technology, and more specifically, to samarium single-atom electrode materials for supercapacitors and their applications. Background Technology
[0002] Supercapacitors, as highly efficient electrochemical energy storage devices, have core application value in transient high-power output and energy recovery applications. Currently, the mainstream electrode materials are carbon-based materials such as activated carbon and porous carbon, which utilize the charge adsorption effect formed by the high specific surface area of these carbon-based materials to achieve energy storage. With the continuous improvement of energy density requirements of energy storage systems, introducing heterogeneous sites with redox activity into carbon-based materials to assist energy storage has become the direction of industry evolution. Rare earth elements, due to their unique 4f electron orbital configuration and rich coordination characteristics, show significant physical advantages in adjusting electrode interface polarity, optimizing ion adsorption energy barriers, and improving charge transport paths.
[0003] However, in the process of integrating rare earth components into carbon-based electrode systems, conventional physical loading or chemical co-precipitation methods result in rare earth components existing in the form of polycrystalline nanoparticles or bulk oxides. This not only limits the atomic utilization rate of active sites, but also, during long-term cycling in alkaline electrolytes, the stress mismatch between large-sized particles and the carbon framework can induce component aggregation or detachment. Specifically, existing technologies mainly have the following shortcomings: 1. Low dispersion of active sites makes it difficult to accurately modulate the electron cloud distribution on the surface at the atomic scale, limiting the potential for interface control; 2. Insufficient bonding strength between active components and the conductive framework, which easily leads to structural instability under frequent ion insertion and extraction impacts, shortening the cycle life of the device; 3. Large charge transfer resistance at the interface, resulting in significant electrochemical polarization under high power output conditions.
[0004] Therefore, the technical problem to be solved by this invention is how to provide a samarium single-atom electrode material for supercapacitors, which solves the problems of low utilization rate of rare earth components and easy structural instability by constructing a stable single-atom coordination structure. Summary of the Invention
[0005] This invention provides a samarium single-atom electrode material for supercapacitors, comprising: Conductive carbon-based framework, samarium single-atom active sites supported on the surface of conductive carbon-based framework, and nitrogen-containing coordination structures supported on the surface of conductive carbon-based framework; Samarium single-atom active sites form nitrogen atoms in nitrogen-containing coordination structures through chemical bonding. Spatial coordination units, samarium single-atom active sites are distributed in an atomically dispersed state on the surface of conductive carbon-based framework channels; In samarium single-atom electrode materials, the mass percentage of samarium is 0.5% to 5.0%, and the mass percentage of nitrogen is 2.0% to 10.0%; the specific surface area of the conductive carbon-based framework is 800 m². 2 / g to 2500m 2 / g, pore volume 0.5cm 3 / g to 2.0cm 3 / g; Samarium single-atom active sites via Spatial coordination units regulate the charge distribution at the electrode material's surface and interface, thereby reducing the charge transfer resistance of the electrode material at a current density of 1 A / g in a 6 mol / L potassium hydroxide electrolyte system. Not higher than 0.5 ; The morphology of samarium single-atom active sites loaded on the surface of a conductive carbon-based framework is controlled by the site constraint of samarium atoms by the nitrogen-containing coordination structure during heat treatment at 700℃ to 950℃. Furthermore, samarium single-atom electrode materials utilize the samarium atoms'... The orbital electron cloud characteristics create local polarization centers on the surface of the conductive carbon-based framework. These local polarization centers enhance the electrostatic attraction of ions in the potassium hydroxide electrolyte to the electrode material interface and reduce the desolvation energy barrier of ions. This reduces the electrochemical polarization of the electrode material during high-rate charge and discharge in alkaline systems and improves the charge exchange rate between the samarium single-atom electrode material and the electrolyte interface. Furthermore, samarium single-atom active sites are anchored to the inner walls of micropores or defect sites of the conductive carbon-based framework, and In spatial coordination units The bond length is 0.23 nm to 0.26 nm; the samarium single-atom electrode material does not contain samarium elemental crystal phase or samarium oxide crystal phase, and the samarium single-atom active sites maintain an atomic-level dispersed structure under ion bombardment in alkaline medium.
[0006] Preferably, the conductive carbon-based framework is selected from one or more of porous carbon, activated carbon, activated carbon black, conductive carbon black, Ketjen black, or nitrogen-doped carbon; the nitrogen-containing coordination structure is composed of coordination bonds formed between lone pairs of electrons provided by o-phenanthroline, pyridine, melamine, urea, or polydopamine and samarium atoms.
[0007] Preferably, the samarium single-atom electrode material exhibits samarium-related properties in X-ray photoelectron spectroscopy. The double peaks and those attributed to the coordinated nitrogen atoms Characteristic peaks; After fitting, the characteristic peaks include a pyridine nitrogen peak at 398.5 eV and a metal-coordinated nitrogen peak at 399.8 eV. The metal-coordinated nitrogen peak is used to characterize the bonding state between samarium and nitrogen.
[0008] Preferably, the conductive carbon-based framework is a carbon particle with a hierarchical pore structure, which includes micropores and mesopores. The volume of micropores with a pore size of less than 2 nm accounts for no less than 60% of the total pore volume, and the mesopores with a pore size of 2 nm to 10 nm are used to provide diffusion channels for ions in the alkaline electrolyte. The samarium single-atom active sites are anchored to the inner wall of the micropores.
[0009] Preferably, the specific capacitance of the electrode material measured in 6 mol / L potassium hydroxide electrolyte is not less than 350 F / g; the specific capacitance retention rate of the electrode material is not less than 80% in the current density range of 1 A / g to 20 A / g; and the localized polarization effect generated by samarium atoms reduces the rate polarization loss caused by ion migration hysteresis, thereby improving the electrode response speed.
[0010] Preferably, the AC impedance spectrum of the samarium single-atom electrode material exhibits a low-frequency diffusion impedance line in the frequency range of 1 MHz to 0.01 Hz, and the angle between the diffusion impedance line and the real axis is not less than 75°; furthermore, in the equivalent circuit model measured for the samarium single-atom electrode material, the charge transfer resistance value representing the interfacial desolvation process is not higher than 0.2. This indicates that samarium single-atom sites have a kinetic optimization effect.
[0011] Preferably, the electrode comprises a positive electrode, a negative electrode, a separator, and an alkaline electrolyte, wherein both the positive and negative electrodes include supercapacitor devices; the supercapacitor devices retain a capacitance of not less than 95% after 10,000 charge-discharge cycles at a working voltage of 0V to 1.0V, and the two electrode materials exhibit high symmetry under the same electrochemical potential window.
[0012] Application of a samarium single-atom electrode material for supercapacitors: A samarium single-atom electrode material for supercapacitors is used as an electrode active material for energy storage in alkaline symmetric supercapacitors.
[0013] The embodiments of the present invention have at least the following beneficial effects: 1. This invention uses a nitrogen-containing coordination structure to stably anchor samarium single atoms onto the surface of a carbon-based conductive framework, forming an atomically dispersed and highly exposed active site system, utilizing the unique properties of samarium. Electron orbitals generate local polarization centers, enhancing the electrostatic attraction of the electrode material's surface and interface to ions in the alkaline electrolyte, improving the interface charge storage efficiency and reducing the ion desolvation energy barrier, thereby improving the ion diffusion kinetics characteristics inside the electrode.
[0014] 2. The samarium single-atom active sites, nitrogen-containing coordination structures, and conductive carbon-based framework work together to construct an efficient electron transport path, reducing the charge transfer resistance between the electrode and electrolyte interface, reducing the electrochemical polarization of the device under high-rate charge and discharge conditions, and enabling the electrode material to maintain a high specific capacitance and response speed under high current density. This solves the problems of excessive potential drop and rapid capacity decay of traditional carbon materials at high power output.
[0015] 3. This invention utilizes the strong chemical bonding between the nitrogen-containing coordination structure and samarium single atoms to effectively suppress the aggregation, migration, and loss of active sites during frequent ion insertion and extraction processes. Combined with the uniform charge distribution of the symmetrical structure, it enhances the structural integrity and chemical stability of the device during long-term cycling, thereby achieving long-term stable electrochemical performance. Attached Figure Description
[0016] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of the invention are illustrated in the drawings by way of example and not limitation, wherein: Figure 1 This is a flowchart illustrating the composition and performance enhancement mechanism of the samarium single-atom electrode material of the present invention. Figure 2 The diagram shows the electrochemical impedance characteristics and kinetic response of the electrode material of this invention in an alkaline system. Figure 3 This is a model diagram of the microscopic distribution and interface charge regulation of the samarium single-atom coordination units of the present invention; Figure 4 This is a constant current charge-discharge voltage response curve of the electrode material of the present invention under different rate conditions. Detailed Implementation
[0017] The principles and spirit of the invention will now be described with reference to the accompanying drawings and several exemplary embodiments. It should be understood that these embodiments are provided merely to enable those skilled in the art to better understand and implement the invention, and are not intended to limit the scope of the invention in any way. Rather, these embodiments are provided to make the invention more thorough and complete, and to fully convey the scope of the invention to those skilled in the art.
[0018] A samarium single-atom electrode material for supercapacitors, comprising: Conductive carbon-based framework, samarium single-atom active sites supported on the surface of conductive carbon-based framework, and nitrogen-containing coordination structures supported on the surface of conductive carbon-based framework; Samarium single-atom active sites form nitrogen atoms in nitrogen-containing coordination structures through chemical bonding. Spatial coordination units, samarium single-atom active sites are distributed in an atomically dispersed state on the surface of conductive carbon-based framework channels; In samarium single-atom electrode materials, the mass percentage of samarium is 0.5% to 5.0%, and the mass percentage of nitrogen is 2.0% to 10.0%; the specific surface area of the conductive carbon-based framework is 800 m². 2 / g to 2500m 2 / g, pore volume 0.5cm 3 / g to 2.0cm 3 / g; Samarium single-atom active sites via Spatial coordination units regulate the charge distribution at the electrode material's surface and interface, thereby reducing the charge transfer resistance of the electrode material at a current density of 1 A / g in a 6 mol / L potassium hydroxide electrolyte system. Not higher than 0.5 ; The morphology of samarium single-atom active sites loaded on the surface of a conductive carbon-based framework is controlled by the site constraint of samarium atoms by the nitrogen-containing coordination structure during heat treatment at 700℃ to 950℃. Furthermore, samarium single-atom electrode materials utilize the samarium atoms'... The orbital electron cloud characteristics create local polarization centers on the surface of the conductive carbon-based framework. These local polarization centers enhance the electrostatic attraction of ions in the potassium hydroxide electrolyte to the electrode material interface and reduce the desolvation energy barrier of ions. This reduces the electrochemical polarization of the electrode material during high-rate charge and discharge in alkaline systems and improves the charge exchange rate between the samarium single-atom electrode material and the electrolyte interface. Furthermore, samarium single-atom active sites are anchored to the inner walls of micropores or defect sites of the conductive carbon-based framework, and In spatial coordination units The bond length is 0.23 nm to 0.26 nm; the samarium single-atom electrode material does not contain samarium elemental crystal phase or samarium oxide crystal phase, and the samarium single-atom active sites maintain an atomic-level dispersed structure under ion bombardment in alkaline medium.
[0019] Preferably, the conductive carbon-based framework is selected from one or more of porous carbon, activated carbon, activated carbon black, conductive carbon black, Ketjen black, or nitrogen-doped carbon; the nitrogen-containing coordination structure is composed of coordination bonds formed between lone pairs of electrons provided by o-phenanthroline, pyridine, melamine, urea, or polydopamine and samarium atoms.
[0020] Preferably, the samarium single-atom electrode material exhibits samarium-related properties in X-ray photoelectron spectroscopy. The double peaks and those attributed to the coordinated nitrogen atoms Characteristic peaks; After fitting, the characteristic peaks include a pyridine nitrogen peak at 398.5 eV and a metal-coordinated nitrogen peak at 399.8 eV. The metal-coordinated nitrogen peak is used to characterize the bonding state between samarium and nitrogen.
[0021] Preferably, the conductive carbon-based framework is a carbon particle with a hierarchical pore structure, which includes micropores and mesopores. The volume of micropores with a pore size of less than 2 nm accounts for no less than 60% of the total pore volume, and the mesopores with a pore size of 2 nm to 10 nm are used to provide diffusion channels for ions in the alkaline electrolyte. The samarium single-atom active sites are anchored to the inner wall of the micropores.
[0022] Preferably, the specific capacitance of the electrode material measured in 6 mol / L potassium hydroxide electrolyte is not less than 350 F / g; the specific capacitance retention rate of the electrode material is not less than 80% in the current density range of 1 A / g to 20 A / g; and the localized polarization effect generated by samarium atoms reduces the rate polarization loss caused by ion migration hysteresis, thereby improving the electrode response speed.
[0023] Preferably, the AC impedance spectrum of the samarium single-atom electrode material exhibits a low-frequency diffusion impedance line in the frequency range of 1 MHz to 0.01 Hz, and the angle between the diffusion impedance line and the real axis is not less than 75°; furthermore, in the equivalent circuit model measured for the samarium single-atom electrode material, the charge transfer resistance value representing the interfacial desolvation process is not higher than 0.2. This indicates that samarium single-atom sites have a kinetic optimization effect.
[0024] Preferably, the electrode comprises a positive electrode, a negative electrode, a separator, and an alkaline electrolyte, wherein both the positive and negative electrodes include supercapacitor devices; the supercapacitor devices retain a capacitance of not less than 95% after 10,000 charge-discharge cycles at a working voltage of 0V to 1.0V, and the two electrode materials exhibit high symmetry under the same electrochemical potential window.
[0025] Application of a samarium single-atom electrode material for supercapacitors: A samarium single-atom electrode material for supercapacitors is used as an electrode active material for energy storage in alkaline symmetric supercapacitors.
[0026] Example 1: This example combines Figures 1 to 4 This document describes a samarium single-atom electrode material for supercapacitors and its applications, such as... Figure 1As shown, a conductive carbon-based framework provides a porous network and support, a nitrogen-containing coordination structure is loaded onto the framework and provides site constraint, and samarium single-atom active sites serve as heterogeneous sites loaded on the framework surface. The three are chemically bonded to form Sm-NC spatial coordination units to maintain the atomic-level dispersion of samarium. The 4f orbital electron cloud characteristics of samarium atoms are utilized to construct a localized charge polarization field or local polarization center at the electrode surface interface. This polarization field enhances electrostatic attraction by strengthening the attraction of ions at the electrode interface. By reducing the polarization in high-rate charge and discharge of the system, the desolvation energy barrier is lowered. At the same time, the charge transfer resistance is reduced by increasing the charge exchange rate at the electrode material interface. This significantly enhances the rate performance and long-term cycle stability under high-power output conditions, ultimately improving the performance of the supercapacitor.
[0027] like Figure 2 As shown, the AC impedance spectrum of the samarium single-atom electrode material illustrates the evolution relationship between the imaginary and real parts of the impedance, where the vertical axis represents the imaginary part of the impedance, and the units are... The horizontal axis represents the real part of the impedance, with units of 1. The curve appears as a diffusion impedance straight line in the low-frequency region of the coordinate system, with an inclination angle of not less than 75° to the real axis. In the high-frequency region, it exhibits a small charge transfer resistance characteristic, which proves that the electrode material has extremely low interfacial desolvation resistance and excellent charge exchange rate in the 6 mol / L potassium hydroxide electrolyte system.
[0028] like Figure 3 As shown, atomic-level coordination domains composed of samarium single-atom active sites and nitrogen-containing coordination structures are atomically dispersed and loaded onto a carbon-based conductive support platform containing hierarchical porous structures and conductive carbon-based frameworks. The components together construct Sm-NC spatial coordination units and thereby form local polarization centers. In the electrochemical operating environment, these centers guide the ion desolvation process through the generated localized charge polarization field, thereby enhancing the interfacial charge transport dynamics and ensuring that the electrode material achieves high-rate cycle stability under high-rate charge and discharge conditions.
[0029] like Figure 4 As shown, the constant current charge-discharge characteristics of samarium single-atom electrode materials under different current densities are reflected by voltage-time curves. The vertical axis represents voltage in V, and the horizontal axis represents time in s. The figure shows the potential response curves at current densities of 1 A / g, 2 A / g, 5 A / g, 10 A / g, and 20 A / g, respectively. All curves show a highly symmetrical triangular distribution, indicating that the material can maintain a very high capacitance retention rate over a wide current density range. Furthermore, the localized polarization effect of samarium atoms effectively reduces the rate polarization loss caused by ion migration hysteresis.
[0030] The above description is merely an explanation of some preferred embodiments of the present invention and the technical principles employed. Those skilled in the art should understand that the scope of the invention as described in the embodiments of the present invention is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of the present invention.
Claims
1. A samarium single-atom electrode material for supercapacitors, characterized in that, include: Conductive carbon-based framework, samarium single-atom active sites supported on the surface of conductive carbon-based framework, and nitrogen-containing coordination structures supported on the surface of conductive carbon-based framework; Samarium single-atom active sites form nitrogen atoms in nitrogen-containing coordination structures through chemical bonding. Spatial coordination units, samarium single-atom active sites are distributed in an atomically dispersed state on the surface of conductive carbon-based framework channels; In samarium single-atom electrode materials, the mass percentage of samarium is 0.5% to 5.0%, and the mass percentage of nitrogen is 2.0% to 10.0%; the specific surface area of the conductive carbon-based framework is 800 m². 2 / g to 2500m 2 / g, pore volume 0.5cm 3 / g to 2.0cm 3 / g; Samarium single-atom active sites via Spatial coordination units regulate the charge distribution at the electrode material's surface and interface, thereby reducing the charge transfer resistance of the electrode material at a current density of 1 A / g in a 6 mol / L potassium hydroxide electrolyte system. Not higher than 0.5 ; The morphology of samarium single-atom active sites loaded on the surface of a conductive carbon-based framework is controlled by the site constraint of samarium atoms by the nitrogen-containing coordination structure during heat treatment at 700℃ to 950℃. Furthermore, samarium single-atom electrode materials utilize the samarium atoms'... The orbital electron cloud characteristics create local polarization centers on the surface of the conductive carbon-based framework. These local polarization centers enhance the electrostatic attraction of ions in the potassium hydroxide electrolyte to the electrode material interface and reduce the desolvation energy barrier of ions. This reduces the electrochemical polarization of the electrode material during high-rate charge and discharge in alkaline systems and improves the charge exchange rate between the samarium single-atom electrode material and the electrolyte interface. Furthermore, samarium single-atom active sites are anchored to the inner walls of micropores or defect sites of the conductive carbon-based framework, and In spatial coordination units The bond length is 0.23 nm to 0.26 nm; the samarium single-atom electrode material does not contain samarium elemental crystal phase or samarium oxide crystal phase, and the samarium single-atom active sites maintain an atomic-level dispersed structure under ion bombardment in alkaline medium.
2. The samarium single-atom electrode material for supercapacitors according to claim 1, characterized in that, The conductive carbon-based framework is selected from one or more of porous carbon, activated carbon, activated carbon black, conductive carbon black, Ketjen black, or nitrogen-doped carbon; the nitrogen-containing coordination structure is composed of coordination bonds formed between lone pairs of electrons provided by o-phenanthroline, pyridine, melamine, urea, or polydopamine and samarium atoms.
3. The samarium single-atom electrode material for supercapacitors according to claim 1, characterized in that, Samarium single-atom electrode materials exhibit X-ray photoelectron spectroscopy characteristics belonging to the element samarium. The double peaks and those attributed to the coordinated nitrogen atoms Characteristic peaks; After fitting, the characteristic peaks include a pyridine nitrogen peak at 398.5 eV and a metal-coordinated nitrogen peak at 399.8 eV. The metal-coordinated nitrogen peak is used to characterize the bonding state between samarium and nitrogen.
4. The samarium single-atom electrode material for supercapacitors according to claim 1, characterized in that, The conductive carbon-based framework consists of carbon particles with a hierarchical pore structure, including micropores and mesopores. The volume of micropores with a pore size of less than 2 nm accounts for no less than 60% of the total pore volume. The mesopores with a pore size of 2 nm to 10 nm are used to provide diffusion channels for ions in the alkaline electrolyte, and samarium single-atom active sites are anchored to the inner wall of the micropores.
5. A samarium single-atom electrode material for supercapacitors according to claim 1, characterized in that, The specific capacitance of the electrode material measured in 6 mol / L potassium hydroxide electrolyte is not less than 350 F / g; the specific capacitance retention rate of the electrode material is not less than 80% in the current density range of 1 A / g to 20 A / g, and the localized polarization effect generated by samarium atoms reduces the rate polarization loss caused by ion migration hysteresis, thereby improving the electrode response speed.
6. The samarium single-atom electrode material for supercapacitors according to claim 1, characterized in that, The AC impedance spectrum of samarium single-atom electrode materials in the frequency range of 1 MHz to 0.01 Hz exhibits a low-frequency diffusion impedance line, with an angle of inclination of no less than 75° to the real axis; furthermore, in the equivalent circuit model measured for samarium single-atom electrode materials, the charge transfer resistance value representing the interfacial desolvation process is no higher than 0.
2. This indicates that samarium single-atom sites have a kinetic optimization effect.
7. A samarium single-atom electrode material for supercapacitors according to claim 1, characterized in that, It includes a positive electrode, a negative electrode, a separator, and an alkaline electrolyte. Both the positive and negative electrodes include supercapacitor devices. The supercapacitor devices retain no less than 95% of their capacitance after 10,000 charge-discharge cycles at a working voltage of 0V to 1.0V, and the two electrode materials exhibit high symmetry under the same electrochemical potential window.
8. An application of a samarium single-atom electrode material for supercapacitors, characterized in that, The samarium single-atom electrode material of claim 1 is used as an electrode active material for energy storage in an alkaline symmetric supercapacitor.