•A novel synthesis of HPCs from interpenetrating polymer networks (IPNs) was reported.•Zinc tartrate was introduced into IPNs to generate uniform mesopores and abundant micropores.•HPCs with a high surface area of 1371 m2 g−1 show 283 F g−1 at 1.0 A g−1 in KOH electrolyte.•HPC electrode shows excellent electrochemical stability up to 10000 cycles.A novel strategy for the synthesis of hierarchical porous carbons (HPCs) from interpenetrating polymer networks (IPNs) for advanced supercapacitor electrodes was reported. There is hydrogen-bonding interaction between resorcinol/formaldehyde (R/F) resol and zinc tartrate, and they were introduced into the inter space of sodium polyacrylate (PAAS) to form IPNs. HPCs with foam-like macropores, uniform mesopores (∼3.8 nm), and abundant micropores were fabricated by direct carbonization of the IPNs. The macropores come from the pyrolysis of PAAS, and the uniform mesopores are ascribed to the synergistic effect of PAAS and zinc tartrate, while the decomposition of IPNs and zinc tartrate and the carbothermal reduction process generate abundant micropores. The resultant HPCs with a high specific surface area up to 1371 m2 g−1 as a supercapacitor electrode exhibit a high specific capacitance of 283 F g−1 at 1.0 A g−1. Besides, the electrode shows high rate capability in which a high current density of 20 A g−1 for charge/discharge operation is available (182 F g−1). Moreover, HPC-1.5 electrode shows excellent electrochemical stability up to 10000 cycles at 2.0 A g−1 with 95.86% retention. This finding highlights new opportunities for well-structured porous carbons derived from IPNs to achieve advanced supercapacitor devices.Hierarchical porous carbons with foam-like macropores, ordered mesopores and abundant micropores were developed from interpenetrating polymer networks to achieve advanced supercapacitor application.

•A simple synthesis of N, S-codoped ultramicroporous carbon nanoparticles (N/S-UCNs) is demonstrated.•Poly(ionic liquid) acts as C, N and S sources, and a self-template to generate ultramicropores.•N/S-UCNs exhibit nanoscale geometry, uniform ultramicropores, high surface area and functional heteroatoms.•N/S-UCNs show high capacitance, excellent rate capability and cycle stability.We demonstrate a highly efficient strategy to synthesize N, S-codoped ultramicroporous carbon nanoparticles (N/S-UCNs) via simple polymerization and carbonization of an ionic liquid (IL). By chemical oxidative polymerization of p-phenylenediamine sulfate ([pPD][2HSO4]) using ammonium persulfate as an initiator, poly(ionic liquid) (PIL) of p[pPD][2HSO4] is obtained, and it acts not only as carbon, nitrogen and sulfur sources, but also as a self-template to generate regular ultramicropores during carbonization. As-prepared N/S-UCNs have nanoscale morphology, uniform ultramicropores (0.50–0.59 nm), high surface area (505–1018 m2 g−1), and high doping content of heteroatoms (N and S). The N/S-UCN carbonized at 600 °C (denoted as N/S-UCN600) achieves an optimum balance between specific surface area and high heteroatom doping content, which exhibits good electrochemical performance when it was used as electrode for supercapacitors. N/S-UCN600 electrode shows a high specific capacitance (225 F g−1 at 2.0 A g−1), long-term cycle stability (90.8% retention after 10,000 cycles), and excellent rate capability (160 F g−1 at 20 A g−1) in alkaline electrolyte. The present PIL-derived strategy to fabricate carbon nanoparticles can be easily carried out without any pretreatment, template or activation procedure, which highlights new opportunity to design heteroatom-doped carbons for advanced energy storage applications.Download high-res image (74KB)Download full-size image

•A solvent- and self-template design of hierarchical porous carbons is reported.•Carbon source acts as a self-template for ultramicropore (0.54 nm) and supermicropore (0.86, 1.3 nm).•The mesopore (3.6 nm) originates from the HAc-assisted solvent template effect.•The carbon electrode shows high capacitance, excellent rate capability and cycle stability.We design a novel solvent- and self-template strategy to fabricate carbon materials with ultramicro-, supermicro- and mesopores through a simple solvothermal reaction of phloroglucinol and terephthaldehyde in dioxane using acetic acid as the catalyst, followed by carbonization. Dioxane serves simultaneously as a solvent in the reaction system and a template to generate mesopores (3.6 nm). Meanwhile, phloroglucinol/terephthaldehyde polymeric organic frameworks act as a self-template to produce regular and well-developed ultramicropores (0.54 nm) and some supermicropores (0.86 and 1.3 nm) during carbonization. High specific surface area (1003 m2 g−1) coupled with hierarchical porous structure endow the resultant carbon electrode excellent electrochemical properties including a satisfactory specific capacitance (214 F g−1 at 1.0 A g−1), excellent rate capability (154 F g−1 at a very high current density of 50 A g−1) as well as superb long-term cycling stability (95.5% retention of initial capacitance after 10000 cycles) in alkaline electrolyte. Compared with traditional synthetic strategy for porous carbons, the present approach can be easily carried out, avoiding tedious procedure, customized hard/soft template or extra activation step, and thus highlights new opportunities towards the simple and highly efficient synthesis of well-designed porous carbons for supercapacitor applications.Download high-res image (210KB)Download full-size image

•A facile and efficient synthesis of nitrogen-doped porous carbons (NPCs) was reported.•Poly (aniline-co-p-phenylenediamine) was directed carbonized/activated to prepare NPCs.•NPCs exhibit unique nanofiber-like structure, high surface area and suitable nitrogen content.•NPCs have high specific capacitance, high rate capability and good cycling stability.We demonstrate a simple synthesis of N-doped porous carbons (NPCs) with nanofiber-like structure via one-step direct carbonization/KOH activation of poly (aniline-co-p-phenylenediamine) (P(ANI-co-PPDA)) at temperatures from 600 to 900 °C in N2 atmosphere. The increase of heat treatment temperature results in an increased specific surface area (from 776 to 2022 m2 g−1) while decreased nitrogen content (from 6.96 to 1.18 wt.%). At 700 °C, the resultant NPCs (denoted as NPC-700) show a high surface area (1513 m2 g−1), high N content (6.43 wt.%) and nanofiber-like morphology. In 6 M KOH electrolyte, NPC-700 electrode has a capacitance as high as 316 F g−1 at 1.0 A g−1 and remains 167 F g−1 at 10.0 A g−1. Besides, NPC-700 electrode exhibits good cycling stability, with capacitance retention of 81.6% after 5000 cycles at 1.0 A g−1. The simple synthesis route and high electrochemical performance of the NPCs show great potential in supercapacitor application.

•Nitrogen-containing ultramicroporous carbon nanospheres (N-UCNs) are fabricated.•Hexamethylenetetramine is used as both a catalyst and nitrogen source to prepare N-UCNs.•Introduction of phloroglucinol/terephthalaldehyde endows ultramicropores for N-UCNs.•N-UCN electrode exhibits a high specific capacitance and excellent cycle stability.In this paper, we report a facile and novel synthesis of nitrogen-containing ultramicroporous carbon nanospheres (N-UCNs) for high performance supercapacitor electrodes. Phloroglucinol and terephthalaldehyde are polymerized to obtain polymer nanoparticles with a mean diameter of ∼15 nm. Hexamethylenetetramine (HMTA) is utilized to substitute ammonia and formaldehyde to polymerize with resorcinol on the surfaces of the polymer colloids for the fabrication of carbon spheres under the Stöber condition. The introduction of phloroglucinol/terephthalaldehyde brings regular ultramicroporous (0.58 nm) to the typical N-UCNs. Besides, the polymerization of resorcinol and HMTA on the surfaces of polymer nanoparticles reduces the diameter of carbon nanospheres from submicrometer sizes to nanoscaled sizes (∼36 nm). Furthermore, the NH4+ released from the hydrolysis of HMTA also acts a source of nitrogen in the carbon framework (1.21 at.%), which can improve the surface properties and electric conductivity of N-UCNs. The typical N-UCNs (N-UCN4.50) with spherical geometry, high surface area (1439 m2 g−1), regular ultramicropores and nitrogen functional groups shows excellent electrochemical performance such as high specific capacitance (269 F g−1 at 1.0 A g−1), long-term cycle stability (90.3% retention after 10000 charge/discharge cycles) in 6 M KOH aqueous electrolyte. This finding provides new opportunities for well-designed carbon nanospheres to achieve advanced supercapacitor electrodes.

Nitrogen-functionalized microporous carbon nanoparticles (N-MCNs) are prepared by direct carbonization of a novel polymer obtained from the Schiff base reaction of terephthalaldehyde and m-phenylenediamine. The carbonization temperature plays a crucial role in the porosity, surface chemistry and capacitive performance for the carbons. N-MCN850 sample shows a much larger specific surface area of 1938 m2 g−1, a higher specific capacitance of 397 F g−1 and 145 F g−1 at the current density of 0.1 and 100 A g−1 in 6 M KOH aqueous electrolyte, respectively. The results indicate its outstanding capacitive behavior and ultrahigh-rate performance. In addition, the electrode shows excellent cycling stability along with 98% of the initial specific capacitance after 5000 charge/discharge cycles.

•A simple oxidative polymerization method was used to fabricate poly(1,5-diaminonapthalene) microsphere.•Poly(1,5-diaminonapthalene) was the first time to be used in preparing nitrogen-containing carbon microspheres (NCMs).•The preparations of poly(1,5-diaminonapthalene) and NCMs are simple and fast.•NCMs carbonized from poly(1,5-diaminonapthalene) exhibit high specific capacitance.Nitrogen-containing carbon microspheres (NCMs) were prepared via directed carbonization of poly(1,5-diaminonapthalene) at different temperatures which was synthesized from 1,5-diaminonapthalene with ammonium persulfate as oxidizing agent. The NCMs were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption-desorption analysis, thermogravimetric-differential thermal analysis (TG-DTA) and X-ray photoelectron spectroscopy (XPS). A typical sample (NCM-700) shows a specific surface area of 403 m2 g−1, nitrogen content of 5.94 at.%, and regular spherical geometry (0.2–0.5 μm in diameter). The electrochemical properties of the NCMs electrodes were investigated by cyclic voltanmetry and galvanostatic charge-discharge measurement. NCM-700 electrode shows a high specific capacitance of 228 F g−1 at a current density of 1.0 A g−1 in 6 M KOH aqueous electrolyte, indicating good capacitive behavior. Besides, the electrode still remains 196 F g−1 (with capacitance retention of 86%) after 5000 charge/discharge cycles, suggesting excellent cycling stability.

In this work we prepared hierarchically ordered micro–mesoporous carbon with enlarged uniform micropores, specifically tailored for the high level adsorption of environmental pollutant bisphenol A (BPA). Sizes of both the primary micropore (1.3 nm) and the primary mesopore (9.0 nm) could be tuned by controlling the condensation behavior of phloroglucinol–terephthalaldehyde resin in a tri-constituent system based on evaporation induced self-assembly. As a result of this the special structure was able to develop high surface area (623–1985 m2 g−1) and large pore volume (0.7–2.3 cm3 g−1). By tuning the micropore size to accommodate the molecular dimensions of BPA, an ultra-high adsorption capacity of 1106 mg g−1 was achieved, three times higher than previously reported values. Kinetic studies revealed that high pore interconnectivity and micropore accessibility were the key to unrestricted adsorbate diffusion through the pore channels and the subsequent high level adsorption. This development sheds new light on the importance of the carbon source in the control of pore size in carbons. The materials hold great potential for application in the purification of industrial process water with high level BPA contamination.

In this paper, size controllable SiO2 nanoparticles synthesized by adjusting the hydrolysis–condensation time and the concentration of tetraethyl orthosilicate (TEOS) in ethanol–water solution in the presence of ammonia as a catalyst were encapsulated within resorcinol–formaldehyde polymer microspheres which were fabricated in the same ethanol–water–ammonia system. After carbonization and following etching with NaOH solution, a series of mesoporous carbon microspheres (MCMs) with an average diameter of 500 nm, a mesopore size of 3.2–14 nm and surface areas of 659–872 m2 g−1 are obtained. As electrode materials for supercapacitors, typical samples of MCMs with a mesopore size of 3.2 nm and 13.5 nm show an initial specific capacitance of 289 and 268 F g−1 under a current density of 1.0 A g−1. After 10000 charge–discharge cycles, the specific capacity remains 261 and 254 F g−1 with the retention of 90.3% and 94.7%. Besides, electrochemical performances influenced by the mesopore size were investigated.

In this paper, we demonstrate the design and synthesis of novel mesoporous Si@C microspheres as anode materials for high-performance lithium-ion batteries. SiO2 nanoparticles modified with hexadecyl trimethyl ammonium bromide are enveloped within resorcinol–formaldehyde polymer microspheres which form in the ethanol–water–ammonia system. Mesoporous voids between Si nanoparticles and the carbon framework are generated after carbonization at 800 °C and magnesiothermic reduction at 650 °C. The resultant Si@C microspheres show regular spherical shapes with a mean diameter of about 500 nm, a mesopore size of 3.2 nm and specific surface areas of 401–424 m2 g−1. Mesoporosity of Si@C microspheres effectively buffers the volume expansion/shrinkage of Si nanoparticles during Li ion insertion/extraction, which endows mesoporous Si@C microspheres with excellent electrochemical performance and cycle stability when they are used as lithium-ion battery anode materials. A typical sample of mesoporous Si@C microspheres presents a specific capacity of 1637 and 1375 mA h g−1 at first discharge and charge under a current density of 50 mA g−1. After 100 cycles, the charge capacity remains 1053 mA h g−1 with a coulombic efficiency of 99%, showing good cycle stability of the anode. This finding highlights the potential application of mesoporous Si@C microspheres in lithium-ion battery anode materials.

Synthesis of carbon materials with enhanced surface areas, and regular and tuned pore diameters is always a great challenge. In this report, ordered mesoporous carbons (OMCs) were synthesized by the one-step assembly of tri-constituents, and the OMCs were applied as an adsorbent for the removal of the highly hazardous water pollutant di(2-ethylhexyl)phthalate (DEHP). Phloroglucinol–formaldehyde based carbon precursor was in situ prepared during the assembly of the tri-constituents, and the surface area and mesopore diameter of the OMCs were tuned by variation of the molar ratio of formaldehyde to phloroglucinol. Small angle X-ray diffraction patterns revealed that the obtained carbons are highly ordered, which is in agreement with the measuring results of transmission electron microscopy at low and high resolution. Scanning electron microscopy images demonstrate that OMC-F2.0 has a hierarchical morphology. Nitrogen adsorption–desorption measurements revealed that the surface area of the OMCs (956–1801 m2 g−1) was dependent on the molar ratio of the carbon precursor constituents (formaldehyde to phloroglucinol). By varying the molar ratio of formaldehyde to phloroglucinol from 1.0 to 4.0, the mesopore diameter of the OMCs was shifted to the higher side, from 2.1 to 3.1 nm. DEHP was efficiently removed from a model water pollutant by the OMCs. OMC-F2.0 achieved the highest adsorption capacity of 364 mg g−1 for the removal of DEHP. The adsorption equilibrium data were treated with the two mathematical models of Langmuir and Freundlich, and the results revealed that decontamination was more favorable with the Langmuir model. This concludes that the removal of DEHP by OMCs depends on the surface area, and the DEHP molecules occupied the porous space of the OMCs in a monolayer manner.

Novel ultramicroporous carbon nanoparticles (UCNs) are synthesized on the basis of solvothermal polymerization of phloroglucinol and terephthaldehyde in dioxane at 220 °C, followed by carbonization at 850 °C. The resultant UCNs show regular 0.54 nm ultramicropores and particle sizes of ∼30 nm. The UCNs as electrode materials for electrical double-layer capacitors (EDLCs) show a specific capacitance of 206 F g–1 at 1.0 A g–1 in a 6 M KOH aqueous solution. The UCN electrode is suitable for charge–discharge operation even at a very high current density of 50 A g–1 coupled with a capacitance of 135 F g–1, indicating excellent high-rate electrochemical performance. The electrochemical capacitance of the UCN electrode has a high retention of 97.6% after 5000 cycles at 1.0 A g–1 tested by a standard three-electrode system (97.3% for the two-electrode cell), which implies a good electrochemical cycling life. This study highlights promising prospects of novel UCNs as advanced electrode materials for EDLCs where a high level of current charge and discharge is required.

In this work we prepared hierarchically ordered micro–mesoporous carbon with enlarged uniform micropores, specifically tailored for the high level adsorption of environmental pollutant bisphenol A (BPA). Sizes of both the primary micropore (1.3 nm) and the primary mesopore (9.0 nm) could be tuned by controlling the condensation behavior of phloroglucinol–terephthalaldehyde resin in a tri-constituent system based on evaporation induced self-assembly. As a result of this the special structure was able to develop high surface area (623–1985 m2 g−1) and large pore volume (0.7–2.3 cm3 g−1). By tuning the micropore size to accommodate the molecular dimensions of BPA, an ultra-high adsorption capacity of 1106 mg g−1 was achieved, three times higher than previously reported values. Kinetic studies revealed that high pore interconnectivity and micropore accessibility were the key to unrestricted adsorbate diffusion through the pore channels and the subsequent high level adsorption. This development sheds new light on the importance of the carbon source in the control of pore size in carbons. The materials hold great potential for application in the purification of industrial process water with high level BPA contamination.

In this paper, we demonstrate the design and synthesis of novel mesoporous Si@C microspheres as anode materials for high-performance lithium-ion batteries. SiO2 nanoparticles modified with hexadecyl trimethyl ammonium bromide are enveloped within resorcinol–formaldehyde polymer microspheres which form in the ethanol–water–ammonia system. Mesoporous voids between Si nanoparticles and the carbon framework are generated after carbonization at 800 °C and magnesiothermic reduction at 650 °C. The resultant Si@C microspheres show regular spherical shapes with a mean diameter of about 500 nm, a mesopore size of 3.2 nm and specific surface areas of 401–424 m2 g−1. Mesoporosity of Si@C microspheres effectively buffers the volume expansion/shrinkage of Si nanoparticles during Li ion insertion/extraction, which endows mesoporous Si@C microspheres with excellent electrochemical performance and cycle stability when they are used as lithium-ion battery anode materials. A typical sample of mesoporous Si@C microspheres presents a specific capacity of 1637 and 1375 mA h g−1 at first discharge and charge under a current density of 50 mA g−1. After 100 cycles, the charge capacity remains 1053 mA h g−1 with a coulombic efficiency of 99%, showing good cycle stability of the anode. This finding highlights the potential application of mesoporous Si@C microspheres in lithium-ion battery anode materials.

In this paper, size controllable SiO2 nanoparticles synthesized by adjusting the hydrolysis–condensation time and the concentration of tetraethyl orthosilicate (TEOS) in ethanol–water solution in the presence of ammonia as a catalyst were encapsulated within resorcinol–formaldehyde polymer microspheres which were fabricated in the same ethanol–water–ammonia system. After carbonization and following etching with NaOH solution, a series of mesoporous carbon microspheres (MCMs) with an average diameter of 500 nm, a mesopore size of 3.2–14 nm and surface areas of 659–872 m2 g−1 are obtained. As electrode materials for supercapacitors, typical samples of MCMs with a mesopore size of 3.2 nm and 13.5 nm show an initial specific capacitance of 289 and 268 F g−1 under a current density of 1.0 A g−1. After 10000 charge–discharge cycles, the specific capacity remains 261 and 254 F g−1 with the retention of 90.3% and 94.7%. Besides, electrochemical performances influenced by the mesopore size were investigated.