Interconnected Porous Carbon Research Articles

NiS2/FeS2 binary nanoparticles confined in interconnected carbon framework with regulated pore structure enabled by citric acid for enhanced sodium storage properties

Recently, pyrite iron disulfide (FeS2) has emerged as a promising anode candidate for sodium-ion batteries (SIBs) due to its high theoretical capacity, affordability, non-toxicity and abundant resource in nature. However, the utilization of FeS2 still confronts the challenges of inferior rate capability and cycling instability for sodium storage, stemming from its low electronic conductivity and substantial volume changes during cycling. Herein, to address these obstacles, NiS2/FeS2 binary nanoparticles encapsulated within a network of interconnected N-doped porous carbon framework (NiS2/FeS2@NPC) are prepared by a successive solid-state ball milling, carbonization and sulfurization strategy with coordination complex of nickel iron Prussian blue analogue (NiFe-PBA) as precursor. The introduction of citric acid plays a critical role for the formation of interconnected carbon framework with regulated internal porous structure, thereby achieving heterostructured NiS2/FeS2@NPC with modulated specific surface area and pore volume. The rational design of interconnected N-doped porous carbon framework and heterogeneous structure guarantees rapid ion/electron transport kinetics, alleviated mechanical stress, and enhanced structural integrity. Benefitting from these advantages, the optimal NiS2/FeS2@NPC-1 electrode exhibits a high reversible capacity (545 mAh/g at 1 A/g), superior rate capability (267 mAh/g at 5 A/g) and ultrastable long-term cycling performance (98.5 % retention over 1000 cycles at 5 A/g). This study presents a novel and efficient design approach for creating durable and high-rate anode materials based on metal sulfides for SIBs.

Jacaranda Flowers Derived Interconnected 3D Porous Carbon for High-Performance Green Supercapacitor

Jacaranda Flowers Derived Interconnected 3D Porous Carbon for High-Performance Green Supercapacitor

Co-crosslinking and anchoring strategy: One-step preparation of N-doped porous carbon for supercapacitors and zinc ion hybrid capacitors

Porous carbon has been widely used in aqueous capacitors due to its wide source, high stability, and controllable preparation. However, the two-step preparation strategy of carbonization and activation with complex operation and serious energy consumption severely limits its further application. In this paper, resorcinol/urea-furfural resin was successfully prepared by using cleaner and greener furfural as raw material and co-crosslinking with resorcinol and urea under the action of catalyst. It is noteworthy that during the curing process, KOH is uniformly anchored inside the resin, so the system only needs one-step high-temperature pyrolysis to obtain a N-doped ant-nest-like three-dimensional interconnected porous carbon material. Consequently, the porous carbon exhibited an impressive specific capacitance of 283F g−1. The assembled symmetrical device shows a capacitance retention of 92 % after 50 000 cycles, showing excellent cycle stability. In addition, the assembled zinc ion hybrid capacitor exhibits a capacitance of 138 mAh g−1 and an energy density of 111 Wh kg−1. The one-step carbonization-doping-activation strategy of this bottom-up in-situ anchoring activator will provide further insights into the hierarchical pore structure design of porous carbon and facilitate the simple and efficient preparation of carbon materials.

Interconnected hierarchical 3D porous carbon derived from Saccharum officinarum L. leaf based on the synergistic effect of KOH for high performance supercapacitor

ABSTRACT Porous carbon has continuously been explored based on biomass for green energy storage due to its abundant, renewable, environmentally friendly resource, economical features, and thermal-chemical stability. Therefore, this study aimed to present porous carbon derived from sugarcane or Saccharum officinarum L. leaf as a precursor, achieved through a KOH activation strategy that combines a two-step pyrolysis process. The synthesized material exhibited an interconnected 3D hierarchical structure, a high specific surface area of 752 m2/g, and a carbon purity of 91.38%. Supercapacitor cell electrode had the highest specific capacitance of 471 F/g induced by 0.5 M KOH. Furthermore, in the 1 M H2SO4 electrolyte solution, the symmetrical supercapacitor cell electrodes produced the highest specific energy of 65.55 Wh/Kg at a specific power output of 329 W/Kg. As a result, a sustainable green method was established by using a biomass energy source that is applied as high-performance supercapacitor cell material.

Taming the anchor and conversion of polyselenides with a self-reinforcing host in lithium–selenium batteries

Energy-dense lithium–selenium (Li–Se) batteries have attracted increasing attention, while their practical application is still hindered, highly relating to the volume expansion and shuttle of Li polyselenides (LiPSes). Herein, a concurrent anchoring/converting strategy is proposed to restrain the dissolution and realize the rapid conversion of LiPSes. A prototypical regulator comprises of polar catalysts embedded in the interconnected porous muti-walled carbon network (i.e., CoSnO3 nanocubes/CNTs), which promises fast electron/ion transportation and inhibits volumetric effect. Moreover, CoSnO3 as redox accelerator enables the stretched Se−Se bonds to decrease the LiPSes bidirectional conversion barrier, achieving accelerated reaction kinetics. Consequently, the self-reinforcing optimized cathode exhibits superior initial capacity of 730 mAh/g, greatly enlarged capacity after 200 cycles (increase by ∼ 32 % than that of the cell with CNTs), and superior rate capacity (153 mAh/g at 2C). This work uncovers the roles of electronic/ionic conductivity and adsorption/catalysis in Li–Se batteries, providing a guidance for taming the utilization and kinetics of cathode from material perspectives.

N/S co-doped interconnected hierarchical porous carbon cathode for zinc-ion hybrid capacitors with high energy density

Porous carbon materials (PCMs) are regarded as one of the most promising cathode materials for zinc-ion hybrid capacitors (ZIHCs) because of their low cost and abundant resource. Nevertheless, it is still a major challenge to enhance the energy density of PCMs-based ZIHCs. Herein, N/S co-doped interconnected hierarchical porous carbons (NS–IHPCs) are prepared from coal tar pitch (CTP) via a MgO@ZIF-8 double-template, in situ activation and N/S doping strategy to tune the microstructure and chemical composition. The as-prepared NS-IHPC1.5 features high specific surface area of 1273 m2 g−1, hierarchical pore structure and suitable heteroatom doping. Consequently, as a cathode, the NS-IHPC1.5-based ZIHC exhibits a high energy density of 125.3 Wh kg−1 at 134.5 W kg−1 and still remains 85.3 Wh kg−1 at 14096.1 W kg−1. The calculation results of density functional theory (DFT) demonstrate that the combination of pyrrole nitrogen and ortho-oxidized sulfur in samples achieves more negative Zn2+ adsorption energy. Correspondingly, the high capacity (166.5 mAh g−1 at 0.2 A g−1) and long cycle stability (94.0 % capacitance retention at 5 A g−1 after 20,000 cycles) are achieved for NS-IHPC1.5. This work offers a reliable way for synthesizing remarkable cathode materials from coal chemical by-products for energy storage.

Soluble starch-derived porous carbon microspheres with interconnected and hierarchical structure by a low dosage KOH activation for ultrahigh rate supercapacitors

The developed porous structure and high density are essential to enhance the bulk performance of carbon-based supercapacitors. Nevertheless, it remains a significant challenge to optimize the balance between the porous structure and the density of carbon materials to realize superior gravimetric and areal electrochemical performance. The soluble starch-derived interconnected hierarchical porous carbon microspheres were prepared through a simple hydrothermal treatment succeeded by chemical activation with a low dosage of KOH. Due to the formation of interconnected spherical morphology, hierarchical porous structure, reasonable mesopore volume (0.33 cm3 g−1) and specific surface area (1162 m2 g−1), the prepared carbon microsphere has an ultrahigh capacitance of 394 F g−1 @ 1 A g−1 and a high capacitance retention of 62.7 % @ 80 A g−1. The assembled two-electrode device displays good cycle stability after 20,000 cycles and an ultra-high energy density of 11.6 Wh kg−1 @ 250 W kg−1. Moreover, the sample still exhibits a specific capacitance of 165 F g−1 @ 1 A g−1 at a high mass loading of 10 mg cm−2, resulting in a high areal capacitance of 1.65 F cm−2. The strategy proposed in this study, via a low-dose KOH activation process, provides the way for the synthesis of high-performance porous carbon materials.

Boosting the Performance of Low-Platinum Fuel Cells via a Hierarchical and Interconnected Porous Carbon Support.

The design of a low-platinum (Pt) proton-exchange-membrane fuel cell (PEMFC) can reduce its high cost. However, the development of a low-Pt PEMFC is severely hindered by the high oxygen transfer resistance in the catalyst layer. Herein, a carbon with interconnected and hierarchical pores is synthesized as a support for the low-Pt catalyst to lower the oxygen transfer resistance. A H2-air fuel cell assembled by Pt/hierarchical porous carbon shows 1610 mW/cm2 peak power density, 2230 mA/cm2 current density at 0.60 V, and only 18.4 S/m local oxygen transfer resistance with 0.10 mgPt/cm2 Pt loading at the cathode, which far exceeds those of various carbon black supports and commercially used Pt/C catalysts. Both the experimental and simulation results have shown the advancement of hierarchical pores toward the high efficiency of oxygen transportation.

Enhanced supercapacitor performance of porous carbon through tuning maceral composition proportion of coal.

Porous carbons (PCs) have been widely investigated as electrode materials for supercapacitors. However, during the preparation process, intense pore formation reactions result in an amorphous carbon structure, which limits the rate performance of the electrode material. Herein, coal is chosen as a carbon source and making use of different reaction characteristics of vitrinite and inertinite with a KOH activator, an interconnected porous structure carbon material with an abundant graphite microcrystalline structure is obtained; the organic relationships between the ratio of vitrinite and inertinite, carbonization conditions, material structure and capacity performance were researched. At the ratio of vitrinite to inertinite of 1 : 2, the sample shows a specific surface area of 2507 m2 g-1 and its ID1/IG is 1.31, which is lower than that of raw coal (1.36). Due to the synergistic effect of the pore structure and graphite microcrystals, PC-900-40 exhibits an improved specific capacitance of 229.40 F g-1 at a current density of 1.0 A g-1, and even at a high current density of 10.0 A g-1 it delivers a specific capacitance of 170.04 F g-1. The PC-900-40//PC-900-40 symmetrical capacitor retains 96% of its initial capacitance after 20 000 cycles.

In Situ Construction of NiCoMn-LDH Derived from Zeolitic Imidazolate Framework on Eggshell-Like Carbon Skeleton for High-Performance Flexible Supercapacitors.

Active compounds based on LDH (ternary layered double hydroxide) are considered the perfect supercapacitor electrode materials on account of their superior electrochemical qualities and distinct structural characteristics, and flexible supercapacitors are an ideal option as an energy source for wearable electronics. However, the prevalent aggregation effect of LDH materials results in significantly compromised actual specific capacitance, which limits its broad practical applications. In this research, a 3D eggshell-like interconnected porous carbon (IPC) framework with confinement and isolation capability is designed and synthesized by using glucose as the carbon source to disperse the LDH active material and enhance the conductivity of the composite material. Second, by constructing NiCoMn-LDH nanocage structure based on ZIF-67 (zeolitic imidazolate framework-67) at the nanometer scale the obtained IPC/NiCoMn-LDH electrode material can expose more active sites, which allows to achieve excellent specific capacitance (2236 F g-1/ 310.6 mAh g-1 at 1 A g-1), good rate as well as the desired cycle stability (85.9% of the initial capacitance upon 5000 cycles test). The constructed IPC/NiCoMn-LDH//IPC ASC (asymmetric supercapacitor) exhibits superior capacitive property (135 F g-1/60.1 mAh g-1 at 0.5 A g-1) as well as desired energy density (40Wh kg-1 at 800W kg-1).

Ultrahigh surface area hierarchical porous carbon derived from biomass via a new KOH activation strategy for high-performance supercapacitor

The study presents a new two-step KOH activation strategy for the facile preparation of three-dimensionally (3D) O-doped interconnected hierarchical porous carbons with ultrahigh surface area (up to 4048.2 m2/g) derived from cost-effective biomass. The resulting porous carbon electrodes exhibited excellent electrochemical performances, with specific capacitances reaching up to 419 F/g at 0.5 A/g and energy densities up to 30.3 W h/kg at 250 W/kg. Meanwhile, the electrodes showed outstanding cycling stability (up to 91.2%) after 20,000 cycles. Compared to the conventional KOH activation method, the new strategy was found to be more effective in improving the porous structure, increasing the specific surface area, and enhancing O-doping of the obtained porous carbons. As a result, the electrochemical performances of the obtained carbon electrode materials were significantly enhanced. The positive effects of this new strategy were confirmed for four types of biomass, including lotus seedpods, rice husk, reed straw and corn cob. Overall, this work provides a simple and effective way to produce superb porous biomass-derived carbon materials for supercapacitor with high performance.

Octahedral Pt–Ni Alloy Nanoparticles Decorated on 3D Interconnected Porous Carbon Nanosheets for Voltammetric Determination of Dihydroxybenzene Isomers

Octahedral Pt–Ni Alloy Nanoparticles Decorated on 3D Interconnected Porous Carbon Nanosheets for Voltammetric Determination of Dihydroxybenzene Isomers

Heterostructured TiN/TiO2 on the hierarchical N-doped carbon for enhancing the polysulfide immobilization and sulfur reduction in lithium-sulfur battery

The commercialization of lithium-sulfur batteries (LSBs) is impeded by their low sulfur utilization and poor cycling stability. Herein, uniformly distributed TiN/TiO2 heterostructures on the hierarchical nitrogen-doped inter-connected multi-scale porous carbon matrix was developed as an effective polysulfide trapper and catalytic accelerator for sulfur reduction reaction. The performance of synthesized TiN/TiO2 heterostructures in LSBs are compared with those of TiN and TiO2. The synergetic effects of strong polysulfide adsorption of TiO2 and superior catalytical conversion ability of TiN draw rapid trap-diffusion-conversion process and enhance the reaction kinetics. This heterostructure-based LSBs exhibit a high specific capacity of 1458.5 mAhg−1 at 0.1 C and 684.9 mAhg−1 at 5 C. Over 1000 cycles, a high capacity of 576 mA h g−1 is retained with a low-capacity decay of 0.030 % per cycle at 2 C. Moreover, a high area capacity value of 6.65 mAh cm−2 is obtained at 0.5C with a high sulfur loading of 8.2 mg cm−2 and low electrolyte/sulfur ratio (E/S) of 4.7. This study provides a novel strategy to develop the transition metal nitride-oxide heterostructure on a three-dimensional porous carbon framework as efficient electrode materials for LSBs application.

One stone for four birds: A “chemical blowing” strategy to synthesis wood-derived carbon monoliths for high-mass loading capacitive energy storage in low temperature

Biomass-derived carbon materials are promising electrode materials for capacitive energy storage. Herein, inspired by the hierarchical structure of natural wood, carbon monoliths built up by interconnected porous carbon nanosheets with enriched vertical channels were obtained via zinc nitrate (Zn(NO3)2)-assisted synthesis and served as thick electrodes for capacitive energy storage. Zn(NO3)2 is proved to function as expansion agent, activator, dopant, and precursor of the template. The dense and micron-scale thickness walls of wood were expanded by Zn(NO3)2 into porous and interconnected nanosheets. The pore volume and specific surface area were increased by more than 430 %. The initial specific capacitance and rate performance of the optimized carbon monolith was approximately three times that of the pristine dense carbon framework. The assembled symmetric supercapacitor possessed a high initial specific capacitance of 4564 mF cm−2 (0–1.7 V) at −40 °C. Impressively, the robust device could be cycled more than 100,000 times with little capacitance attenuation. The assembled zinc-ion hybrid capacitor (0.2–2 V) delivered a large specific capacitance of 4500 mF cm−2 at −40 °C, approximately 74 % of its specific capacitance at 25 °C. Our research paves a new avenue to design thick carbon electrodes with high capacitive performance by multifunctional Zn(NO3)2 for low-temperature applications.

Exploring potassium trifluoroacetate as a novel electrolyte for enhancing energy density of biomass-derived carbon-based supercapacitors and improving electrolyte-electrode adaptability

Improving the energy density by expanding the operating voltage of electrolytes and enhancing the charge storage capacity of electrode materials is crucial for the development of supercapacitors. This work proposes a potassium trifluoroacetate (CF3COOK, CFK) electrolyte for improving the energy density of supercapacitors without sacrificing the high power density and long-cycle performance while developing honeycomb-like interconnected hierarchical porous carbons (HIHPCs) with controlled pore size distribution, large specific surface area (3028 m2 g−1), interconnected pore structure, and high electrical conductivity (2.01 S cm−1) from waste biomass to match the proposed CFK electrolyte for harvesting high charge storage capability. The prepared HIHPCs exhibit excellent electrochemical performance in the proposed CFK electrolyte, achieving a high specific capacitance of up to 409 F g−1 over a wide operating voltage window of −1.0 to 0.9 V, with high coulomb efficiency, low internal resistance, good rate capability, and perfect electrochemical stability. Symmetric supercapacitors constructed using the obtained HIHPCs and the proposed CFK electrolyte can operate stably at 1.9 V and deliver high specific energy of 24.8 Wh kg−1 at 237.8 W kg−1 with good cycling stability. The effectiveness of the proposed CFK electrolyte as an ideal electrolyte with extended electrochemical stability windows to significantly improve the energy density of aqueous supercapacitors was verified. This work presents a promising approach for developing high-performance aqueous supercapacitors with potential applications in renewable energy systems.

Nitrogen-doped porous carbon nanofibers embedded with Cu/Cu3P heterostructures as multifunctional current collectors for stabilizing lithium anodes in lithium-sulfur batteries

Among the various beyond-lithium-ion battery systems, lithium-sulfur batteries (Li-S) have been widely considered as one of the most promising technologies owing to their high theoretical energy density. However, the irregular Li plating/stripping and infinite volume change associated with low Coulombic efficiency and safety concerns of host-less lithium anode hinder the practical application of Li-S batteries. Herein, Cu/Cu3P heterostructure-embedded in carbon nanofibers (Cu/Cu3P-N-CNFs) are developed as multifunctional current collectors for regular lithium deposition. The 3D porous interconnected carbon skeleton endows effectively reduced local current density and volume expansion, meanwhile the Cu/Cu3P particles function as nucleation sites for uniform lithium plating. Consequently, the developed ion/electron-conducting skeleton delivers remarkable electrochemical performances in terms of high Coulombic efficiency for 500 cycles at 1 mA cm−2, and the accordingly symmetric cell exhibits long-term cyclic duration over 1500 h with a low voltage hysteresis of ∼ 80 mV at 1 mA cm−2. Moreover, Li-S full cells paired with the developed anode and S@CNTs cathode also show superior rate capability (568 mAh/g at 2C) and excellent stability of >500 cycles at 0.2C, further demonstrating the great potential of Cu/Cu3P-N-CNFs as promising current collectors for advanced lithium-metal batteries.

Novel Three-Dimensional Hierarchical Porous Carbon Probe for the Discovery of N-Glycan Biomarkers and Early Hepatocellular Carcinoma Detection.

Due to the highly heterogeneous nature of hepatocellular carcinoma (HCC), the accurate diagnosis of HCC during the early phase of development is still a challenging task. Therefore, the further development of novel diagnostic methods by discovering new biomarkers is required to improve the rate of HCC diagnosis in the early phase. In this work, an oxygen-modified three-dimensional interconnected porous carbon probe is designed and fabricated to profile the differences of N-glycans in human serum from health controls (H) and patients with hepatic dysfunction (HD) and HCC for the discovery of new biomarkers with HCC development. Excitingly, we discovered that the expression levels of 12 serum N-glycans were gradually increased from H to patients with HD and eventually to patients with HCC. Moreover, two machine learning models established based on these 12 serum N-glycans reached a satisfactory accuracy for predicting HCC development where the receiver operating characteristic curve arrived above 0.95 for distinguishing healthy controls and patients with liver diseases (HD or HCC) and the ROC curve arrived at 0.85 for distinguishing HD and HCC. Our work not only developed a new method for the large-scale characterization of serum N-glycans but also provided valuable guidance for accurate and highly sensitive diagnosis of early liver cancer development in a non-invasive manner.

Defect-rich hierarchical porous carbon prepared by homogeneous activation for high performance capacitive deionization

Defect engineering has emerged as an effective approach for modulating the electronic structure and physicochemical properties of carbon materials. Porous carbon materials with abundant defects are regarded as prospective electrode materials for capacitive deionization. Nevertheless, constructing defect-rich carbon materials and revealing the relationship between desalination capacity and intrinsic defects remains a daunting challenge. Herein, the defect-rich interconnected hierarchical porous carbon (IHPC) was fabricated via sol-gel method to form a supramolecular hydrogel containing highly dispersed K+ using coal, polyvinylpyrrolidone, and KOH as raw materials, followed by homogeneous activation. The spectroscopic studies coupled with density functional theory calculations demonstrate that the introduction of intrinsic defects can optimize the distribution of electron density to promote charge transfer, thereby enhancing saline ions adsorption. The plentiful adsorption sites, robust charge transfer kinetics and rapid ion diffusion derived from the multiple advantageous characteristics of IHPC facilitate a high desalination capacity of 31.25 mg g−1 in 800 mg L−1 NaCl solution. Meanwhile, it also presented excellent desalination performances in KCl (31.42 mg g−1), CaCl2 (29.55 mg g−1), and MgCl2 (26.65 mg g−1) solutions. The higher desalination capacity, rapid salt adsorption rate as well as outstanding cycling stability rank the IHPC as a potential candidate for capacitive deionization applications.

Correction: Facile synthesis of interconnected layered porous carbon framework for high-performance supercapacitors

Correction: Facile synthesis of interconnected layered porous carbon framework for high-performance supercapacitors

Covalent sulfur/CoS2-decorated honeycomb-like carbon hierarchies for high-performance sodium storage with ultra-long high-rate cycling stability

Transition metal sulfides (TMSs) with high theoretical sodium storage capacity have been regarded as one of the most competitive and promising anode materials for sodium-ion batteries. Nevertheless, great challenges still exist for TMS to achieve long-cycle life owing to the poor conductivity and volume expansion during the sodiation/desodiation process. The conventionally used pure carbon coating method can effectively solve the above problems. However, the low sodium ion storage capability of carbon will decrease the capacity of the anode. Thus the functionalization of well-designed carbon nanostructures with exotic elements (e.g., sulfur) or high-specific-capacity materials has been regarded as an efficient route to enhance sodium storage performance. Herein, we developed a facile strategy to incorporate covalent sulfur and CoS2 nanoparticles into honeycomb-like carbon matrices (denoted as S/CoS2@C), where sulfur is vaporized under vacuum and reacted with the Co-decorated carbon hierarchies, leading to the formation of CoS2 nanoparticles as well as the covalent C–Sx–C bonds. Consequently, the as-prepared S/CoS2@C composite demonstrates excellent sodium storage performance, with high initial coulomb efficiency (ICE) of 83 % and capacity retention of 95 % (478.5 mAh g−1) after 700 cycles at 0.2 A g−1, and an outstanding high-rate long-term cycling stability with a high reversible capacity of 396.1 mAh g−1 after 5000 cycles at 2 A g−1 (an average decay rate of only 0.0014 %). Furthermore, electrochemical analyses reveal that both covalent sulfur and CoS2 contribute to the sodium storage capacity via a predominantly surface-induced capacitive process, and the well-designed S/CoS2@C composite with encapsulation of covalent sulfur and CoS2 into the highly interconnected porous carbon matrices efficiently buffer the volume changes and well maintain the electrode integrity/conductivity upon sodiation/desodiation cycling.