N/S co-doped coal-based porous carbon spheres as electrode materials for high performance supercapacitors

N/S co-doped porous carbon spheres (NSPCSs) were prepared by a simple ultrasonic spray pyrolysis (USP) using the mixed solution of coal oxide and l-cysteine, and without a subsequent activation process. The surface properties of carbon materials have been successfully modified by the concurrent incorporation of N and S. So the capacitive performance of NSPCSs was greatly enhanced. It is used as a supercapacitor electrode to achieve a high specific capacitance of 308 F g⁻¹ at a current density of 1 A g⁻¹ and 90.2% capacitance retention even after 10 000 cycles at 5 A g⁻¹. These numerical results show that the supercapacitors based on coal-based carbon materials have great potential in high performance electrochemical energy storage.

N/S co-doped porous carbon spheres were prepared using one step strategy for high performance supercapacitors.     

Dual-doped hierarchical porous carbon derived from biomass for advanced supercapacitors and lithium ion batteries

Nowadays, designing heteroatom-doped porous carbons from inexpensive biomass raw materials is a very attractive topic. Herein, we propose a simple approach to prepare heteroatom-doped porous carbons by using nettle leaves as the precursor and KOH as the activating agent. The nettle leaf derived porous carbons possess high specific surface area (up to 1951 m² g⁻¹), large total pore volume (up to 1.374 cm³ g⁻¹), and high content of nitrogen and oxygen heteroatom doping (up to 17.85 at% combined). The obtained carbon as an electrode for symmetric supercapacitors with an ionic liquid electrolyte can offer a superior specific capacitance of 163 F g⁻¹ at 0.5 A g⁻¹ with a capacitance retention ratio as high as 67.5% at 100 A g⁻¹, and a low capacitance loss of 8% after 10 000 cycles. Besides, the as-built supercapacitor demonstrates a high specific energy of 50 W h kg⁻¹ at a specific power of 372 W kg⁻¹, and maintains 21 W h kg⁻¹ at the high power of 40 kW kg⁻¹. Moreover, the resultant carbon as a Li-ion battery anode delivers a high reversible capacity of 1262 mA h g⁻¹ at 0.1 A g⁻¹ and 730 mA h g⁻¹ at 0.5 A g⁻¹, and maintains a high capacity of 439 mA h g⁻¹ after 500 cycles at 1 A g⁻¹. These results demonstrate that the nettle leaf derived porous carbons offer great potential as electrodes for advanced supercapacitors and lithium ion batteries.

Nettle leaf derived nitrogen and oxygen dual-doped porous carbons exhibit great potential as anodes for high performance supercapacitors and lithium ion batteries.     

A green approach to prepare hierarchical porous carbon nanofibers from coal for high-performance supercapacitors

A green method is designed to obtain hierarchical porous carbon nanofibers from coal. In the work, deionized water, coal, polyvinyl alcohol and Pluronic F127 are used as the aqueous solution, carbon source, spinning assistant and soft template for spinning, respectively. As electrode materials for supercapacitors, the obtained hierarchical porous carbon nanofibers exhibit a high specific capacitance of 265.2 F g⁻¹ at 1.0 A g⁻¹ in 6 M KOH, a good rate performance with a capacitance of 220.3 F g⁻¹ at 20.0 A g⁻¹ with the retention of 83.1% and a superior cycle stability without capacitance loss after 20 000 charge/discharge cycles at 10.0 A g⁻¹. Compared with the carbon nanofibers constructed without Pluronic F127, the enhanced electrochemical performance of the sample benefits from a larger contact surface area and the mesoporous structure formed by decomposition of Pluronic F127 and good structural stability. This work not only provides a green route for high-value utilization of coal in energy storage, but also paves a new way to make hierarchical porous carbon nanofibers from coal for supercapacitor electrodes with high specific capacitance and long cycle life.

A green method is designed to obtain hierarchical porous carbon nanofibers from coal for supercapacitor electrodes with high specific capacitance and long cycle life.     

Hierarchically porous N-doped carbon derived from supramolecular assembled polypyrrole as a high performance supercapacitor electrode material

Rationally designed precursors of N-doped carbon are crucial for high performance carbon materials of supercapacitor electrodes. Herein, we report a scalable preparation of hierarchically structured N-doped carbon of micro/meso porous nanofiber morphology by using a supramolecular assembled polypyrrole as the precursor. The influences of the dose of supramolecular dopant on final products after carbonization and sequential chemical activation were investigated. The interconnected nanofiber backbone allows better electron transport and the optimized hierarchically porous structure of the material exhibits a large specific surface area of 2113.2 m² g⁻¹. The N content of the carbon is as high as 6.49 atom%, which is favorable to improve the supercapacitive performance via additional reversible redox reaction over pure carbon. The hierarchically porous N-doped carbon electrode delivered an outstanding specific capacitance of 435.6 F g⁻¹ at 0.5 A g⁻¹, significantly higher than that of the control sample derived from undoped polypyrrole samples. Moreover, the capacitance retention is as high as 96.1% after 5000 cycles. This precursor''s structural control route is readily applicable to various conducting polymers, and provides a methodology to design carbon materials with advanced structure for developing high-performance supercapacitor electrode materials.

Hierarchically porous N-doped carbon with optimized morphology exhibits an enhanced specific capacitance of 435.6 F g⁻¹ at 0.5 A g⁻¹ and 96.1% capacitance retention after 5000 cycles in 1 M H₂SO₄.     

Hierarchical porous carbons from carboxylated coal-tar pitch functional poly(acrylic acid) hydrogel networks for supercapacitor electrodes

A gel carbonization strategy for the synthesis of hierarchical porous carbons (HPCs) from carboxylated coal-tar pitches (CCP) functional poly(acrylic acid) (PAA) hydrogel networks for advanced supercapacitor electrodes was reported. The amphiphilic CCP and PAA polymer could be easily self-assembled to gel by the major driving force of hydrogen bonding and π–π stacking. The HPCs containing interconnected macro-/meso-/micropores were fabricated by direct carbonization of the dried hydrogels. The resultant HPCs with a high specific surface area and total pore volume of 1294.6 m² g⁻¹ and 1.34 cm³ g⁻¹ respectively, as a supercapacitor electrode exhibit a high specific capacitance of 292 F g⁻¹ at 1.0 A g⁻¹ in two-electrode system. The electrode also exhibits ultra-long cycle life with a capacitance retention as high as 94.2% after 10 000 cycles, indicating the good electrochemical stability. Furthermore, the concept of such hierarchical architecture and synthesis strategy would expand to other materials for advanced energy storage systems, such as Na-ion batteries and metal oxides for supercapacitors.

As a supercapacitor electrode exhibit a high specific capacitance of 292 F g⁻¹ at 1.0 A g⁻¹.     

A novel porous carbon material derived from the byproducts of bean curd stick manufacture for high-performance supercapacitor use

The exploitation of efficient renewable energy resources and the promotion of added value of agricultural products are always hot topics. In this study, we present a novel porous carbon material for high performance supercapacitor applications made from the byproduct of bean curd stick manufacture. The as-prepared carbon material possesses a hollow interconnected structure with a large specific surface area (2609 m² g⁻¹), while containing 5.01% oxygen and 1.75% nitrogen heteroatoms. Therefore, besides electrical double-layer capacitance, it can also produce additional pseudocapacitance to enhance the overall capacitance. Benefiting from these advantages of structure and composition, the bean curd stick based porous carbon material demonstrates a high specific capacitance of 405 F g⁻¹ at 0.5 A g⁻¹. Moreover, the presented porous carbon material based symmetric supercapacitor also offers a high energy density (11.35 W h kg⁻¹ at a power density of 125 W kg⁻¹). All the above findings indicate that the byproduct of bean curd stick manufacture is an excellent optional material for preparing high-performance supercapacitor material. Simultaneously, this work also provides an effective strategy for adding value to agricultural products.

Preparation of heteroatom-functionalized porous carbon derived from byproducts of bean curd stick manufacture as an electrode material for high performance supercapacitors.     

Nitrogen and oxygen Co-doped porous carbon derived from yam waste for high-performance supercapacitors

It is a considerable challenge to produce a supercapacitor with inexpensive raw materials and employ a simple process to obtain carbon materials with a high specific surface area, rich pore structure, and appropriate doping of heterogeneous elements. In the current study, yam waste-derived porous carbon was synthesized for the first time by a two-step carbonization and KOH chemical activation process. An ultra-high specific surface area of 2382 m² g⁻¹ with a pore volume of 1.11 cm³ g⁻¹ and simultaneous co-doping of O–N was achieved for the optimized sample. Because of these distinct features, the optimized material exhibits a high gravimetric capacitance of 423.23 F g⁻¹ at 0.5 A g⁻¹ with an impressive rate capability at 10 A g⁻¹, and prominent cycling durability with a capacity retention of 96.4% at a high current density of 10 A g⁻¹ after 10 000 cycles in 6 M KOH in a three-electrode system. Moreover, in 6 M KOH electrolyte, the assembled symmetrical supercapacitor provides a large C of 387.3 F g⁻¹ at 0.5 A g⁻¹. It also presents high specific energy of 34.6 W h kg⁻¹ when the specific power is 200.1 W kg⁻¹ and a praiseworthy specific energy of 8.3 W h kg⁻¹ when the specific power is 4000.0 W kg⁻¹ in 1 M Na₂SO₄ electrolyte. Thus, this study provides reference and guidance for developing high-performance electrode materials for supercapacitors.

3D porous carbon with ultra-high specific surface area and excellent electrochemical performance is synthesized by a simple activation and carbonization process through adopting biomass yam waste as raw material.     

Nitrogen-doped hierarchical porous CNF derived from fibrous structured hollow ZIF-8 for a high-performance supercapacitor electrode

Hollow ZIF-8 was assembled into fiber to fabricate a nitrogen-doped hierarchical porous CNF electrode, which exhibits specific capacitance of 394 F g⁻¹ at 1 A g⁻¹ and excellent rate performance with a retention of up to 76.1% at 20 A ⁻¹, exceeding those of many previously reported 1D carbon materials.

Hollow ZIF-8 shells were assembled into fibers to obtain nitrogen-doped hierarchical porous carbon nanofibers for excellent supercapacitor application.     

Preparation of nitrogen-doped porous carbons for high-performance supercapacitor using biomass of waste lotus stems

In this study, advanced nitrogen-doped porous carbon materials for supercapacitor was prepared using low-cost and environmentally friendly waste lotus stems (denoted as LS-NCs). Nitrogen in the surface functionalities of LS-NCs was investigated using X-ray photoelectron spectroscopy analysis. The sum of pyridine nitrogen (N-6) and pyrrolic/pyridinic (N-5) contents accounted for 94.7% of the total nitrogen and significantly contributed to conductivity. Pore structure and surface area of activated carbons were measured using the Brunauer–Emmett–Teller method. A maximum specific surface area of 1322 m² g⁻¹ was achieved for LS-NCs. The porous carbons exhibited excellent electrochemical properties with a specific capacitance of 360.5 F g⁻¹ at a current density of 0.5 A g⁻¹ and excellent cycling stability (96% specific capacitance retention after 5000 cycles). The above findings indicate that taking advantage of the unique structure of abundant waste lotus stem provides a low-cost and feasible design for high-performance supercapacitors.

In this study, advanced nitrogen-doped porous carbon materials for supercapacitor was prepared using low-cost and environmentally friendly waste lotus stems (denoted as LS-NCs).     

Nitrogen and sulfur co-doped graphene aerogel for high performance supercapacitors

The development of high energy density and power density supercapacitors is very necessary in energy storage and application fields. A key factor of such devices is high-performance electrode materials. In this work, nitrogen and sulfur co-doped graphene aerogels (N/S-GA) were synthesized using graphene oxide as the precursor and 2-mercapto-1-methylimidazole as both the reducing agent and the N/S doping agent. The pore size distribution of the as-prepared N/S-GA was measured and the N/S-GA possesses a hierarchical porous structure. As an electrode material of supercapacitors, the N/S-GA could provide a suitable structure for charge accommodation and a short distance for ion transport. When 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF₄) ionic liquid was used as the electrolyte, the specific capacitance of the N/S-GA electrode material reached 212 F g⁻¹ and 162 F g⁻¹ at the current densities of 1 A g⁻¹ and 10 A g⁻¹, respectively. And the energy density and average power density of the N/S-GA based supercapacitor could reach 117 W h kg⁻¹ and 1.0 kW kg⁻¹ at 1 A g⁻¹, 82 W h kg⁻¹ and 9.5 kW kg⁻¹ at 10 A g⁻¹, respectively. It is believed that the N/S-GA material can be used in high-performance supercapacitors.

A nitrogen and sulfur co-doped graphene aerogel (N/S-GA) was synthesised in one step, and N/S-GA based supercapacitors exhibited high performance.     

Controllable synthesis of aluminum doped peony-like α-Ni(OH)2 with ultrahigh rate capability for asymmetric supercapacitors

Ion substitution and micromorphology control are two efficient strategies to ameliorate the electrochemical performance of supercapacitors electrode materials. Here, Al³⁺ doped α-Ni(OH)₂ with peony-like morphology and porous structure has been successfully synthesized through a facile one-pot hydrothermal process. The Al³⁺ doped α-Ni(OH)₂ electrode shows an ultrahigh specific capacitance of 1750 F g⁻¹ at 1 A g⁻¹, and an outstanding electrochemical stability of 72% after running 2000 cycles. In addition, the Al³⁺ doped α-Ni(OH)₂ electrode demonstrates an excellent rate capability (92% retention at 10 A g⁻¹). Furthermore, by using this unique Al³⁺ doped α-Ni(OH)₂ as the positive electrode and a hierarchical porous carbon (HPC) as the negative electrode, the assembled asymmetric supercapacitor can demonstrate a high energy/power density (49.6 W h kg⁻¹ and 14 kW kg⁻¹). This work proves that synthesizing an Al³⁺ doped structure is an effective means to improve the electrochemical properties of α-Ni(OH)₂. This scheme could be extended to other transition metal hydroxides to enhance their electrochemical performance.

Ion substitution and micromorphology control are two efficient strategies to ameliorate the electrochemical performance of supercapacitors electrode materials.     

Needle-like CoO nanowire composites with NiO nanosheets on carbon cloth for hybrid flexible supercapacitors and overall water splitting electrodes

A nanoscale core–shell NiO@CoO composite is prepared on flexible carbon cloth for electrodes in supercapacitors and overall water splitting. The needle-like CoO nanowires with NiO nanosheets as the active materials improve the elemental constituents as well as surface area. The NiO@CoO electrode boasts a capacity of 2.87 F cm⁻² (1024.05 F g⁻¹) at 1 A g⁻¹ current density, and even at a large current density of 20 A g⁻¹ the retention ratio is 80.9% after 5000 cycles. The excellent specific capacity with high rate capability can be ascribed to the unique structure which increases the area of the liquid–solid interface and facilitates electron and ion transport, improving the utilization efficiency of active materials. The asymmetric hybrid supercapacitor prepared with the core–shell electrode shows the energy output of 40.3 W h kg⁻¹ at 750 W kg⁻¹ with a better retention (71.7%) of specific capacitance after 15 000 cycles. In addition, linear sweep voltammetry is performed to assess the performance of the electrode in water splitting and the electrode shows excellent activity in the OER as manifested by a Tafel slope of 88.04 mV dec⁻¹. Our results show that the bifunctional structure and design strategy have large potential in energy applications.

A nanoscale core–shell NiO@CoO composite is prepared on flexible carbon cloth for electrodes in supercapacitors and overall water splitting.     

Porous g-C3N4 covered MOF-derived nanocarbon materials for high-performance supercapacitors

Supercapacitors with high power density and long cycle life have shown great potential in energy storage supply for modern electronic devices. Among the component parts of supercapacitors, electrode materials with high electrical conductivity, large surface area and porosity are critical to the energy storage performances of devices. Here, we report a porous g-C₃N₄ covered MOF-derived nanocarbon material with large specific surface area and high nitrogen doping level as an electrode material for supercapacitors. The large surface area provides high capacity for ion accommodation during electrochemical processes, and the high nitrogen doping facilitates electron and ion transport with extra pseudocapacitance. The supercapacitor based on the as-synthesized material delivers a high specific capacity of 106 F g⁻¹ at current density of 1 A g⁻¹ as well as good rate capability. Furthermore, the device presents good cycling stability with capacitance retention of 91% even after 10 000 cycles at 1 A g⁻¹ under 0.8 V. This study presents a new insight into the design of nanocomposite materials with high energy storage capability and will accelerate the practical application of supercapacitors in future.

Here, we report a porous g-C₃N₄ covered MOF-derived nanocarbon material with large surface area and high nitrogen doping for supercapacitors.     

Biomass-derived O,N-codoped hierarchically porous carbon prepared by black fungus and Hericium erinaceus for high performance supercapacitor

Biomass-derived carbon materials have been widely researched due to their advantages such as low cost, environmental friendliness, readily available raw materials. Black fungus and Hericium erinaceus contain many kinds of amino acids. In this paper, unique O, N-codoped black fungus-derived activated carbons (FAC_X), and Hericium erinaceus-derived activated carbons (HAC_X) were prepared by KOH chemical activation under different temperatures without adding additional reagents containing nitrogen and oxygen functional groups, respectively. As electrode materials of symmetric supercapacitors, FAC₂ and HAC₂ calcined at 800 °C exhibited the highest specific capacitance of 209.3 F g⁻¹ and 238.6 F g⁻¹ at 1.0 A g⁻¹ in the two-electrode configuration with 6.0 M KOH as the electrolyte, respectively. The X-ray photoelectron spectroscopy confirmed that the as-synthesized FAC_X and HAC_X contained small amounts of nitrogen and oxygen elements. Moreover, heteroatom-doped FAC₂ and HAC₂ electrode materials shown excellent rate performance (84.1% and 75.0% capacitance retention at 20 A g⁻¹, respectively). By comparison, the oxygen-rich hierarchical porous carbon (HAC₂) shows higher specific capacitance and energy density and longer cycling performance. Nevertheless, carbon-rich hierarchical porous carbon (FAC₂) indicates excellent rate performance. Biomass-derived heteroatom self-doped porous carbons are expected to become ideal active materials for high performance supercapacitor.

Biomass-derived heteroatom self-doped porous carbons are expected to become ideal active materials for high performance supercapacitor.     

Facile synthesis of bio-based nitrogen- and oxygen-doped porous carbon derived from cotton for supercapacitors

Biomass-derived O- and N-doped porous carbon has become the most competitive supercapacitor electrode material because of its renewability and sustainability. We herein presented a facile approach to prepare O/N-doped porous carbon with cotton as the starting material. Absorbent cotton immersed in diammonium hydrogen phosphate (DAP) was activated at 800 °C (CDAP800s) and then was oxidized in a temperature range of 300–400 °C. The electrochemical capacitance of the impregnated cotton was significantly improved by doping with O and N, and the yield was improved from 13% to 38%. The sample oxidation at 350 °C (CDAP800-350) demonstrated superior electrical properties. CDAP800-350 showed the highest BET surface area (1022 m² g⁻¹) and a relatively high pore volume (0.53 cm³ g⁻¹). In a three-electrode system, the CDAP800-350 electrodes had high specific capacitances of 292 F g⁻¹ in 6 M KOH electrolyte at a current density of 0.5 A g⁻¹. In the two-electrode system, CDAP800-350 electrode displayed a specific capacitance of 270 F g⁻¹ at 0.5 A g⁻¹ and 212 F g⁻¹ at 10 A in KOH electrolyte. In addition, the CDAP800-350-based symmetric supercapacitor achieved a high stability with 87% of capacitance retained after 5000 cycles at 5 A g⁻¹, as well as a high volumetric energy density (18 W h kg⁻¹ at 250 W kg⁻¹).

Biomass-derived O- and N-doped porous carbon has become one of the most competitive supercapacitor electrode material because of its renewability and sustainability.     

Hierarchical NaFePO4 nanostructures in combination with an optimized carbon-based electrode to achieve advanced aqueous Na-ion supercapacitors

Recent trends in sodium-ion-based energy storage devices have shown the potential use of hollow structures as an electrode material to improve the performance of these storage systems. It is shown that, in addition to the use of hierarchical structures, the choice of the complementary carbon electrode determines the final performance of Na-ion-based devices. Here, we present simple synthesis strategies to prepare different structured carbonaceous materials that can be upscaled to an industrial level. Individual carbon materials deliver specific capacitance ranges from 120 to 220 F g⁻¹ at a current density of 1 A g⁻¹ (with excellent capacity retention). These structures, when combined with hollow NaFePO₄ microspheres to fabricate an aqueous supercapacitor, show as high as a 1.7 V working potential window and can deliver a maximum energy density of 25.29 W h kg⁻¹ capacity retention. These values are much higher than those reported by NaFePO₄ solid particles and randomly chosen carbon structure-based supercapacitors.

An aqueous supercapacitor with hollow NaFePO₄ microsphere structures combined with rGO shows as high as a 1.7 V working potential window and can deliver a maximum energy density of 25.29 W h kg⁻¹ capacity retention.     

Preparation of phosphorus-doped porous carbon for high performance supercapacitors by one-step carbonization

Biomass-derived porous carbon has received increasing attention as an energy storage device due to its cost-effectiveness, ease of manufacture, environmental friendliness, and sustainability. In this work, phosphorus-doped porous carbon was prepared from biomass sawdust (carbon source) and a small amount of phosphoric acid (P-doping source and gas expanding agent) by one-step carbonization. For comparison, parallel studies without phosphate treatment were performed under the same conditions. Benefiting from the addition of phosphoric acid, the prepared carbon material has higher carbon yield, higher specific area and micropore volume. Due to the heteroatom doping of P in the carbon material, the optimized PC-900 sample not only exhibits high specific capacitances of 292 F g⁻¹ and 169.4 F g⁻¹ at current densities of 0.1 A g⁻¹ and 0.5 A g⁻¹, respectively, but also excellent cycle longevity (98.3% capacitance retention after 5000 cycles) in 1 M H₂SO₄. In addition, the supercapacitor exhibits a high energy density of 10.6 W h kg⁻¹ when the power density is 224.8 W kg⁻¹ at a discharge current density of 0.5 A g⁻¹. This work proposes a sustainable strategy to reuse waste biomass in high-performance and green supercapacitors for advanced energy storage equipment.

P-doped porous carbon can be prepared by one-step carbonization using biomass sawdust impregnated with a small amount of phosphoric acid.     

NH4V4O10 nanobelts vertically grown on 3D TiN nanotube arrays as high-performance electrode materials of supercapacitors

High performance supercapacitor without binders has attracted wide attention as an energy storage device. In this work, novel NH₄V₄O₁₀ nanobelts were successfully synthesized and decorated into TiN nanotube arrays by a simple hydrothermal method. The as-prepared no-binder electrode hybrids exhibited excellent electrochemical performances with a specific capacitance of 749.0 F g⁻¹ at 5 mV s⁻¹ and a capacity retention of 85.7% after 200 cycles, which makes it an appealing candidate for electrode materials of supercapacitors.

NH₄V₄O₁₀ nanobelts were synthesized and decorated into TiN nanotube arrays as supercapacitor electrode with a specific capacitance of 749.0 F g⁻¹ at 5 mV s⁻¹ and a capacity retention of 85.7% after 200 cycles.     

Facile preparation of 3D porous agar-based heteroatom-doped carbon aerogels for high-energy density supercapacitors

The fabrication of heteroatom-doped porous carbon materials with high electrical conductivity and large specific surface area via an environmentally friendly route is critical and challenging. Herein, nitrogen and oxygen co-doped agar porous carbon (APC) was developed for supercapacitors via a one-step carbonization method with agar as the raw material and ammonia as the activator and nitrogen source. APC outperformed pectin porous carbon, tamarind porous carbon, and the previously reported carbon-based supercapacitors with a high capacitance retention of 72% even from 0.5 A g⁻¹ to 20 A g⁻¹ and excellent cycling stability in 6 M KOH solution (retained after 10 000 cycles) with a rate of over 98.5%. Furthermore, the APC electrode-based symmetric device exhibited an impressive energy density of 20.4 W h kg⁻¹ and an ultra-high power density of 449 W kg⁻¹ in 1 M Na₂SO₄ electrolyte together with excellent cycling stability (103.2% primary capacitance retentivity after 10 000 cycles). This study offers a novel method for the synthesis of nitrogen heteroatom-doped hierarchical porous carbon materials for performance-enhanced energy storage devices.

N and O co-doped agar porous carbon (APC) as electrode materials exhibit excellent performance. A respectable energy density of 20.4 W h kg⁻¹ and an ultra-high power density of 449 W kg⁻¹, as well as excellent cycle stability in 1 M Na₂SO₄ electrolyte.     

Polymer network-derived nitrogen/sulphur co-doped three-dimensionally interconnected hierarchically porous carbon for oxygen reduction,lithium-ion battery,and supercapacitor

Rational design and simple synthesis of carbon-based materials with high electrocatalytic activity are essential for their practical applications in electrochemical energy conversion and storage devices. Herein, we report the synthesis of nitrogen, sulfur co-doped three-dimensional interconnected hierarchically porous carbon (NSHPC) by zinc acetate assisted pyrolysis of polymer networks. The thus-synthesized NSHPC has a specific surface area of 1057 cm² g⁻¹ with the coexistence of micro- and meso-pores. As metal-free electrocatalyst, the NSHPC exhibits a promising activity towards oxygen reduction reactions as evidenced by the slightly negative shift of half-wave potential compared with commercial Pt/C catalyst. The assembled lithium ion battery using NSHPC as anode delivers the reversible capacity of 740 and 470 mA h g⁻¹ at current densities of 2 and 5 A g⁻¹ without performance decay after 1000 charge–discharge cycles. Moreover, the assembled supercapacitor using NSHPC as electrode has the capacitance of 203 F g⁻¹ at 1 A g⁻¹.

Polymer networks are efficient precursors for large scale production of hierarchical porous carbon.