Three-dimensional Porous Carbon Networks Research Articles

The collaborative effect of Ni3S2-NiO heterojunction and porous carbon network modified lithium-sulfur battery separator for effectively inhibiting polysulfides shuttle

As an important part of lithium-sulfur battery (LSB), separator not only provides ion transport channel but also plays a key role in ensuring battery safety. However, the aperture of the commercial separator polypropylene (PP) is relatively large, which cannot effectively inhibit the migration of polysulfides generated during the charging and discharging process between the positive and negative electrodes, resulting in a decrease in the cycle stability of LSB. In this work, a modified LSB separator Ni3S2-NiO@AC-4@PP is designed, which is anchored by Ni3S2-NiO heterojunction on volcanic rock-like three-dimensional porous carbon network (AC) as the functional interlayer. The AC possesses a large specific surface area and excellent electrical conductivity, creating sufficient space for the physical and chemical adsorption of insoluble polysulfides. The Ni3S2-NiO heterojunction is embedded and attached to the AC, which helps to hinder the diffusion of polysulfides and accelerate the redox reaction. It is also confirmed by density functional theory (DFT) calculation that Ni3S2-NiO heterojunction inhibited the shuttle of polysulfides through the adsorption capacity of NiO and the catalytic activity of Ni3S2. Thus, the Ni3S2-NiO@AC-4@PP battery exhibits an elevated initial specific capacity of 1027.8 mAh g−1 at 0.2C, maintaining long-term stability after 200 cycles with the capacity retention rate of 81.4 %. At the higher current density (2C), Ni3S2-NiO@AC@PP battery demonstrates durable cycle with the capacity retention rate of 91.3 %. This study proposes a new feasible strategy to obtain high-performance, low-cost modified separators by designing functional interlayers with excellent adsorption and catalytic properties.

Fluoride-samarium(III) doped hierarchically porous carbon nanofibers as thin separator coating layer with excellent adsorption and outstanding catalysis of lithium polysulfide for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are promising for next-generation energy storage due to their high energy density and low cost. However, challenges such as the “shuttle effect,” slow reaction kinetics, and lithium dendrite growth hinder their performance. In this study, we developed fluoride-samarium(III) doped hierarchically porous carbon nanofibers (SmF3-PCNFs) and coated them onto separators. These three-dimensional porous carbon networks confined LiPSs, while polar SmF3 nanoparticles acted as efficient chemical anchors and catalysts. Simultaneously, the polar fluoride interfaces between the SmF3-PCNFs and cathode also can accelerate the transport of lithium ions and enhance the adhesion between them, enabling them to accommodate the huge volume changes of the sulfur cathode during cycling and improve long-cycle stability. Moreover, the modified separator with excellent lithium affinity also enables uniform lithium deposition to reduce lithium dendrite growth. Combining these advantages, the assembled Li-S battery with SmF3-PCNFs modified separator exhibits a high initial discharge specific capacity of 1068.2 mAh g−1 and retains a capacity of 655.3 mAh g−1 after 750 cycles (with a decay rate of only 0.05 % per cycle), and the Coulombic efficiency remains above 93 %. This work will pave a new design path for the preparation of modified separators in high-performance Li-S batteries.

N/O/P ternary-doped coal-based hierarchical porous carbon networks for high lithium-ion storage performance

Constructing porous structure and surface modification are effective ways to enhance the Li-ion storage performance of commercial graphite anode for lithium-ion batteries (LIBs). Herein, nitrogen, oxygen and phosphorus ternary-doped coal-based hierarchical porous carbon networks (N/O/P-CCNs) were prepared through liquid oxidation combined with self-assembly method. The N/O/P-CCNs have a three-dimensional porous carbon network structure formed by cross-linking carbon nanosheets with an appropriate specific surface area (321 m2 g−1) and distribution of micro-, meso- and macropore, while the surfaces of carbon nanosheets are doped with nitrogen, oxygen and phosphorus. Due to unique hierarchical porous structure and the synergistic effect of ternary doping, the N/O/P-CCNs anode exhibits excellent Li-ion storage properties with initial reversible capacity of 1079 mAh g−1, which is much higher than that of coal-based graphite anode (382 mAh g−1). Besides, the N/O/P-CCNs anode also has superior rate capability (336 and 275 mAh g−1 at 1.0 and 2.0 A g−1) and cycle stability with a high capacity retention (near 100 % after 100 cycles). The excellent electrochemical performance is not only related to the hierarchical pore structure that can provide efficient channels for lithium-ion transport, but also to the ternary-doping of nitrogen, oxygen and phosphorus that can provide more active sites for lithium-ion storage and enhance conductivity. This work provides a novel and effective design strategy for developing high-performance anode materials for LIBs.

Cobalt-doped porous carbon nanofibers with three-dimensional network structures as electrocatalysts for enhancing oxygen reduction reaction

In this study, we design and prepare the cobalt-doped porous carbon nanofibers (Co@PCNFs) as efficient electrocatalysts based on the electro-blow spinning method and carbonization processes. The porous Co@PCNFs has the three-dimensional porous carbon network structures as the fast electron transport channels and endow the materials with high specific surface area. The central metal Co atoms will be converted into metal nanoparticles with high efficient catalysis in the PCNFs after the carbonization treatment. And the carbonized product still inherits the nanometer size of the ZIF-67 (40–50 nm) precursor, which is more beneficial to expose more active sites. These advantages enable the prepared electrocatalyst to exhibit excellent oxygen reduction reaction (ORR) performance (onset potential of 0.91 V vs. RHE, half-wave potential of 0.857 V vs. RHE), which is very close to commercial Pt/C. More importantly, the obtained Co@PCNFs catalyst exhibited superior electrochemical stability and methanol tolerance over commercial Pt/C under alkaline conditions. The work will open up novel options for various fields such as high performance Zn-air batteries and fuel cells in the future.

Single Cu atoms confined in N-doped porous carbon networks by flash nanocomplexation as efficient trifunctional electrocatalysts for Zn-air batteries and water splitting

Constructing efficient trifunctional single-atom electrocatalysts is exceedingly alluring and challenging for enhancing the efficiency of water splitting and Zn-air batteries (ZABs). Herein, a novel N-doped porous carbon network (SC-CuSA-NC) catalyst with Cu single atoms is constructed via flash nanocomplexation (FNC) technology and a double-network gel-limiting strategy. The novelty of this method lies in the combination of physical confinement and chemical confinement by FNC, which enables uniform spatial isolation and atomic-level dispersion of Cu atoms in the hydrogel, effectively inhibits the migration of Cu during synthesis, and achieves accurate and controllable preparation of Cu single atoms catalyst. Benefiting from the highly active Cu–N4 sites and distinct interconnected three-dimensional porous carbon network, SC-CuSA-NC shows superior ORR/OER/HER performance. Significantly, the ZAB assembled by SC-CuSA-NC displays a high specific capacity (775.0 mAh g−1) and could effectively drive water splitting (1.58 V at 10 mA cm−2). This work expands the synthesis method of single-atom catalysts and provides a new approach for the accurate and controllable synthesis of electrocatalysts for water splitting and ZABs.

Co-CoF2 heterojunctions encapsulated in N, F co-doped porous carbon as bifunctional oxygen electrocatalysts for Zn-air batteries

We present a rational design of hierarchical porous Co-N x framework with Co-CoF 2 heterojunctions (PCF@CCFCNT) uniformly dispersed in the holes for advanced Zn-air batteries. This multi-scale strategy from structure to active site design delivers a high power density of 184 mW cm −2 , long-term charge/discharge cycling over 1000h in an ambient environment, which demonstrates a high practical application ability. • Porous Co-N x framework with Co-CoF 2 heterojunctionswere successfully fabricated. • The porous structure leads to synergistically optimization of ion, electron, and gas transport. • Co-CoF 2 heterojunctions and Co-N x results in excellent OER and ORR performance. • PCF@CCFCNT-based Zn-air battery presents a long durability and a high peak power density. The structural design and atomic adjustment of the catalyst are the main factors that regulate the intrinsic electrocatalytic activity. Herein, we report a novel and facile strategy of synthesizing three-dimensional porous carbon network by polymer-assisted molding strategy. The porous carbon framework with Co-CoF 2 and carbon nanotubes (PCF@CCFCNT) was directly obtained by the calcination, in which Co-CoF 2 heterojunctions uniformly dispersed in the interconnected holes. Benefiting from the special hierarchical porous morphology, the dual-function catalytic activity of Co-CoF 2 heterojunctions and existence of Co-N x species, the as-obtained PCF@CCFCNT composites exhibit excellent performance in the oxygen evolution reaction (η = 300 mV@10 mA cm −2 ), as well as outstanding oxygen reduction reaction performance in alkaline medium (E 1/2 = 0.852 V, vs RHE). Moreover, as an air electrode in Zn-air batteries (ZABs), PCF@CCFCNT demonstrates a large peak power density of 184 mW cm −2 and superior long-term stability, which is much more stable than the one consisting of commercial Pt/C. This finding not only shows a simple composite design to achieve high-performance ZABs but also may stimulate the rapid development of 3D hierarchical porous electrocatalysts for advanced energy technologies.

N-Doped Carbon Materials Modified with Cobalt Nanoparticles As Catalysts for Oxygen Reduction Reaction

The oxygen reduction reaction is one of the main reactions which occur in fuel cells and other renewable energy technologies. In addition to this, oxygen reduction reaction on the cathode is more difficult reaction compare to anodic reaction, because the greater amount of Pt must be used as the cathode material to catalyze the reaction. The search for an efficient electrocatalyst for oxygen reduction reaction to replace platinum in fuel cell cathode materials is one of the hottest topics in electrocatalysis in relation to platinum high price and limited resources. That is the reason why researches put an effort in finding low cost, higher efficient and great performance catalysts. Various alternative catalysts have been studied including noble or non-noble metal catalysts. It is known that carbon is considered as one of the most promising electrocatalytic material for replacement of Pt. Therefore, researches have been trying multifarious methods with the purpose to increase the activity of the carbon. The fabricated N-doped carbon materials, 2D nitrogen-doped hierarchically porous carbon, N and P co-functionalized three-dimensional porous carbon networks, N, S-codoped porous exfoliated carbon nanosheets, N-doped carbon nanotubes, nitrogen-doped carbide-derived carbon catalysts or nitrogen-rich carbon dots decorated graphene oxide hybrid were described as materials having very similar electrocatalytic activity towards oxygen reduction reaction to Pt. Moreover N-doped carbon catalysts show high electrocatalytic activity forward oxygen reduction reaction in both – acidic and alkaline media. Among the many non-noble metal catalysts, metal/nitrogen/carbon composites containing Fe, Cu, Co metals are a promising alternative to Pt.In this study, the biological waste, such as black liqueur and alder wood chips, were used for the fabrication of catalytic material. Activated carbon and black liqueur were doped with cheap nitrogen precursor dicyandiamide and used as substrates for the deposition of cobalt nanoparticles (CoNPs) with the aim to use them as electrocatalysts for the oxygen reduction reaction. The synthesized catalysts were characterized by Inductively Coupled Plasma Optical Emission Spectroscopy, Field Emission Scanning Electron Microscopy, Transmission Electron Microscopy and X-ray Photoelectron Spectroscopy. Activity of the prepared catalysts was evaluated for oxygen reduction reaction in O2 - saturated 0.1 M NaOH solution employing the rotating disk electrode method. Electrocatalytic activity of CoNPs-N-doped black liqueur and CoNPs-N-doped activated carbon catalysts were compared with catalytic activities of commercial Pt/C wt. 46.4 % Pt.It has been found that the N-doped black liqueur and N-doped activated carbon substrates show high electro-catalytic activity for the oxygen reduction reaction. The modification of N-doped black liqueur and N-doped activated carbon with Co nanoparticles enhanced electrocatalytic activity of catalysts towards oxygen reduction reaction. It has been determined that the N-doped black liqueur and CoNPs- N-doped black liqueur samples demonstrated more similar electrocatalytic activity towards oxygen reduction reaction to Pt/C.

In situ growth of MoS2 on three-dimensional porous carbon for sensitive electrochemical determination of bisphenol A

Three-dimensional porous carbon network (3D-C) was used as the substrate for the in situ growth of molybdenum disulfide (MoS2) through a wet chemistry method. The obtained 3D-C@MoS2 nanocomposite exhibited a porous structure, high surface area and good electrical conductivity. By using the 3D-C@MoS2 nanocomposite as a novel electrode modifier, the electrochemical oxidation peak current of bisphenol A (BPA) was greatly enhanced with a lowered background current. The improved sensitivity benefits from adsorption of BPA onto MoS2 surface, the large surface area and good conductivity of the 3D-C@MoS2 nanohybrid. By using differential pulse voltammetry (DPV), we observed a good linearity with BPA levels in the range of 0.001–10 μM, with a detection limit estimated to be 0.5 nM (S/N = 3). The 3D-C@MoS2 modified electrode could be reused for several times in spite of the accumulation of BPA, and the fabrication reproducibility is excellent. The prepared 3D-C@MoS2 modified electrode showed higher selectivity to BPA than several other phenolic compounds due to their different electrochemical oxidation potentials and the enhanced accumulation property of BPA at the 3D-C@MoS2 surface. The BPA contents in plastic product and environmental water samples were determined with the proposed method.

Self-Assembly Three-Dimensional Porous Carbon Networks for Efficient Dielectric Attenuation.

Zeolitic imidazolate framework (ZIF-8)-derived ZnO/nanoporous carbon (NPC) aligned in a three-dimensional porous carbon network (3DPCN) is designed to form a multiporous network nanostructure to absorb electromagnetic waves. The porous 3DPCN structure acts as the electronic pathway and the nucleation locus for ZIF-8 particles. Meanwhile, the conductive networks could also provide more routes for electron transfer. With good impedance matching and attenuation characteristics, ZnO@NPC/3DPCN shows enhanced microwave response where the minimum reflection loss of -35.7 dB can be achieved with a 10 wt % filler. Our study not only exploits the new system of lightweight absorbers but also further reveals the changing of electromagnetic parameters and absorbing properties by heat treatment, which may lead to a new way to design novel lighter multiporous network nanostructures.

Facile synthesis of three-dimensional porous carbon networks for highly stable sodium storage

Novel three-dimensional porous carbon network (3D-PC) anode was developed by a facile in situ NaCl-template method utilizing citric acid as carbon source. The synthesis process involves the dissolution of NaCl and citric acid in deionized water, citric acid coated on NaCl template during freeze-drying process, carbonization of the composites, and removal of the template with water. The resultant 3D-PC presents high electrical conductivity, large specific surface area, sufficient active sites, large interlayer distance, and high mechanical flexibility, which are contributed to the efficient Na-storage. Therefore, the 3D-PC anode displays enhanced rate performance of 101 mAh g−1 at 1000 mA g−1 and extremely long cycle life of 138 mAh g−1 after 2000 cycles at 200 mA g−1. The unique synthesis strategy coupled with the excellent Na-storage performance ensures 3D-PC a promising anode material for low-cost sodium-ion batteries.

P-Doped Three-Dimensional Porous Carbon Networks as Efficient Metal-Free Electrocatalysts for ORR

Nowadays, developing low-cost, high-performance metal-free catalysts of full cells is becoming increasingly prevalent. In this work, P-doped carbon is prepared through a one-step pyrolysis and double activation methods. When the amount of NaH2PO2 is 0.4 g, the obtained catalyst shows three-dimensional nanostructure porous and exhibits the better electrochemical performance, including more positive onset potential (−0.04 V), the largest limiting current (−5.83 mAcm−2 at 0.6 V), and the best stability. The obtained catalyst also has large surface area (943 m2g−1). Moreover, the active sites and defects of the carbon material formed by the synergistic effect between NaH2PO2 and ZnCl2 improved the electrochemical performance. The facile preparation and excellent electrochemical performance shows that the proposed process is a promising candidate for full cell catalysts.

N and P co-functionalized three-dimensional porous carbon networks as efficient metal-free electrocatalysts for oxygen reduction reaction

Developing low-cost and high-performance metal-free oxygen reduction reaction (ORR) catalysts for fuel cells is highly desirable but still full of challenges. In this study, nitrogen and phosphorus co-functionalized three-dimensional (3D) porous carbon networks (NPCN) have been prepared by pyrolysis the zero-dimensional carbon quantum dots (CQDs) and a supermolecular gel of self-assembled melamine and amino trimethylene phosphonic acid (ATMP). The resultant NPCN catalysts possess unique 3D networks-like porous architecture, large specific surface area (743 m2 g−1) and abundant edge defects. As a catalyst for ORR, the optimized NPCN-900 (pyrolyzed at 900 °C) displays positive onset potential at 0.92 V and 0.74 V (vs. RHE) in alkaline and acidic media respectively, which are roughly close to those of Pt/C (0.93 V and 0.80 V). Additionally, the NPCN-900 exhibits longer-term stability and strong endurance to methanol over a wide pH range of aqueous media, which is much superior to that of Pt/C. Considering the outstanding activity of NPCN-900, it can be worked as a prospective metal-free catalyst to substitute commercial Pt/C for ORR in fuel cells.

Scalable preparation of porous micron-SnO2/C composites as high performance anode material for lithium ion battery

Nano tin dioxide-carbon (SnO2/C) composites prepared by various carbon materials, such as carbon nanotubes, porous carbon, and graphene, have attracted extensive attention in wide fields. However, undesirable concerns of nanoparticles, including in higher surface area, low tap density, and self-agglomeration, greatly restricted their large-scale practical applications. In this study, novel porous micron-SnO2/C (p-SnO2/C) composites are scalable prepared by a simple hydrothermal approach using glucose as a carbon source and Pluronic F127 as a pore forming agent/soft template. The SnO2 nanoparticles were homogeneously dispersed in micron carbon spheres by assembly with F127/glucose. The continuous three-dimensional porous carbon networks have effectively provided strain relaxation for SnO2 volume expansion/shrinkage during lithium insertion/extraction. In addition, the carbon matrix could largely minimize the direct exposure of SnO2 to the electrolyte, thus ensure formation of stable solid electrolyte interface films. Moreover, the porous structure could also create efficient channels for the fast transport of lithium ions. As a consequence, the p-SnO2/C composites exhibit stable cycle performance, such as a high capacity retention of over 96% for 100 cycles at a current density of 200 mA g−1 and a long cycle life up to 800 times at a higher current density of 1000 mA g−1.

N,P-Codoped Carbon Networks as Efficient Metal-free Bifunctional Catalysts for Oxygen Reduction and Hydrogen Evolution Reactions.

The high cost and scarcity of noble metal catalysts, such as Pt, have hindered the hydrogen production from electrochemical water splitting, the oxygen reduction in fuel cells and batteries. Herein, we developed a simple template-free approach to three-dimensional porous carbon networks codoped with nitrogen and phosphorus by pyrolysis of a supermolecular aggregate of self-assembled melamine, phytic acid, and graphene oxide (MPSA/GO). The pyrolyzed MPSA/GO acted as the first metal-free bifunctional catalyst with high activities for both oxygen reduction and hydrogen evolution. Zn-air batteries with the pyrolyzed MPSA/GO air electrode showed a high peak power density (310 W g(-1) ) and an excellent durability. Thus, the pyrolyzed MPSA/GO is a promising bifunctional catalyst for renewable energy technologies, particularly regenerative fuel cells.

Highly uniform silicon nanoparticle/porous carbon nanofiber hybrids towards free-standing high-performance anodes for lithium-ion batteries

Novel silicon nanoparticle/porous carbon nanofiber (Si/PCNF) hybrids with high Si loading (52wt.%) have been designed and fabricated through a simple electrospinning. The Si/PCNF of uniform fiber diameter has exhibited high specific surface area and unique porous structure. The continuous three-dimensional porous carbon networks have effectively provided strain relaxation for Si volume expansion/shrinkage during lithium insertion/extraction. In addition, the carbon matrix could largely minimize the direct exposure of Si to the electrolyte, thus substantially improving the structural stability of Si. Moreover, the porous structure could also create efficient channels for the fast transport of lithium ions. As a consequence, this novel Si-based hybrid material has exhibited stable cycling performance (ca. 870mAhg−1 at 0.1Ag−1 after 100 cycles) in the absence of binders and conducting additives, promising great potential as a free-standing anode for lithium ion batteries.