3D Hierarchical Porous Carbon Research Articles

An environment-friendly method to prepare fulvic acid-based porous carbon for high energy density supercapacitors

Low energy density (Eg) of supercapacitors (SCs) severely limits their industrial applications. Enhancing the voltage window of SCs is an effective method to achieve a square-fold increase in Eg. 3D hierarchical porous carbons (FPs) with high yield (14.5 %) and high conductivity (87 S m−1) were prepared by an interfacial self-assembly method using low-cost biomass fulvic acid (FA) as a carbon resource and employs P123 as a structure-directing agent. The soft template P123 establishes a key role in the formation of FPs. It not only enhances the pore connectivity of FPs but also induces an interfacial orientation of the carbon micro-domains in FA. Furthermore, high-temperature annealing can repair the carbon network of FPs, thus FPs are endowed with high electrical conductivity, low carbon defects and low oxygen content (4.1 at.%), which leads to superior voltage-withstanding properties. By exploiting its structural advantages, the optimized sample FP800 exhibits a specific surface area of 1938 m2 g−1, sp2 carbon (88.5 %), a high mesopore ratio of 30.76 % and a high voltage of 3.2 V in commercial TEABF4/PC electrolyte. It gets high Cg of 107 F g−1 at 1 A g−1, high rate performance (C10/0.05) of 82.0 % and maximum Eg of 39.1 Wh kg−1. Furthermore, it also obtains an ultra-stable lifespan with 90.6 % capacity retention after 60,000 cycles. Compared to FP750 and FP850, FP800 has a more reasonable electrochemical performance.

B, N co-doped 3D hierarchical porous carbon entrapping sulfur for high performance of Li-S batteries

The dissolution and diffusion of polysulfide compounds in lithium-sulfur (Li-S) batteries restrict their cyclic stability. The sulfur hosts are the key to achieve good cyclic stability for Li-S batteries. Here, a three-dimensional hierarchical heteroatoms B, N-doped porous carbon (BNC) was prepared as a new sulfur host. The active sulfur can be anchored inside the cathode due to the incorporation of atomic functional groups formed by B and N co-doping, which enhances the adsorption capacity between the cathode and lithium polysulfides. The resulting BNC loaded sulfur (S@BNC) cathode exhibits high specific capacity and electrochemical stability. Specifically, the reversible specific capacity of S@BNC cathode achieved a reversible specific capacity of 1056.8 mAh g−1 at 0.1 C. After 500 cycles, the specific capacity still remains 618.5 mAh g−1 at 0.2 C, which corresponds to a capacity decay rate of 0.0776 %. The results suggest that BNC has great potential as the sulfur host for achieving high performance of Li-S batteries.

3D hierarchical porous N-doped carbon nanoarchitecture coated bimetallic phosphides as a highly efficient bifunctional electrocatalyst for overall water splitting

As the energy and ecological crises are increasingly grim, it is challengeable but extremely attractive to fabricate highly efficient and low-cost bifunctional electrocatalysts for overall water splitting (OWS). Herein, a bimetallic phosphide embedded in N-doped hierarchical porous carbon (CoP/Ni2P@NHPC) framework was successfully constructed by calcination and phosphorization of cobalt–nickel coordination polymer nanoflowers (Co/Ni CPNFs), which were obtained by a facile hydrothermal process. Benefitting from their fascinating architecture and composition, the as-prepared CoP/Ni2P@NHPC exhibits outstanding electrochemical properties for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with small Tafel slopes (103.9 mV dec-1, 62.58 mV dec-1) and ultralow overpotentials (275 mV, 159 mV at 10 mA cm−2) in alkaline medium. Additionally, the CoP/Ni2P@NHPC can be used as a bifunctional catalyst in a two-electrode water splitting device, and it only requires a low cell voltage of 1.55 V to attain the current density of 10 mA cm−2. Meanwhile, the CoP/Ni2P@NHPC also present admirable durability (at least 20 h) under long-term electrolysis. This work gives inspiration for the preparation of highly active bifunctional electrocatalysts for OWS.

Green one-pot synthesis of spongy hierarchical porous carbon with interconnected channels towards high-performance supercapacitors

Green and convenient construction of three-dimensional (3D) hierarchical porous carbon for supercapacitors (SCs) has drawn widespread attention due to their effective ion adsorption and transport capabilities. In this study, sucrose-derived spongy hierarchical porous carbon materials were successfully prepared using a one-step carbonization process with sodium chloride and sodium bicarbonate acting as collaborative pore-forming agents. The optimal carbon material exhibits a distinct 3D spongy structure with interconnected channels, high specific surface area, and proper pore size distribution. Consequently, it displays a specific capacitance of 263.5 F g−1 at 0.5 A g−1 and could retain 221.9 F g−1 (84.21%) at 20 A g−1. Additionally, the as-fabricated device delivers a supreme energy density of 17.0 Wh kg−1 at 80 W kg−1 and possesses exceptional cycling stability of 94.36% after 20000 cycles. Through the combination of raw material carbonization properties and synergistic pore-making mechanisms, the present work provides an effective and eco-friendly approach for fabricating 3D spongy hierarchical porous carbon materials with interconnected channels for high-performance SCs.

Hierarchical porous carbon aerogels as a versatile electrode material for high-stability supercapacitors.

Supercapacitors (SCs), as new energy storage devices with low cost and high performance, urgently require an electrode material with good pore structure and developed graphitization. Herein, we report a 3D hierarchical porous structured carbon aerogel (CA) obtained via dissolving-gelling and a subsequent carbonizing process. The gelling process was realized by using different types of anti-solvents. The carbon aerogel-acetic acid (CA-AA) has a specific surface area of 616.97 m2 g-1 and a specific capacitance of 138 F g-1 which is superior to cellulose-based active carbon. The CA was assembled into a SC, which showed excellent cycle stability. After charging and discharging 5000 times at the current density of 1 A g-1, the capacitance retention ratio of CA-AA reaches 102%. In addition, CA-AA has an energy density of 10.06 W h kg-1 when the power density is 181.06 W kg-1. It provides a choice for non-activation to effectively regulate the porous structure of biomass carbon materials.

Coordination polymer and layered double hydroxide dual-precursors derived polymetallic phosphides confined in N-doped hierarchical porous carbon nanoflower as a highly efficient bifunctional electrocatalyst for overall water splitting

Controllable construction of proficient electrocatalyst with 3D hierarchical architecture to achieve low cost and high efficient overall water splitting is of great significance to the sustainable development. Hereby, trimetallic phosphides confined in N-doped carbon nanoflowers (CoNiP/CoNiFeP@NCNFs) were fabricated using CoNi coordination polymer nanoflowers/CoNiFe layered double hydroxide (CoNi CPNFs/CoNiFe LDH) as precursors followed by phosphorization. Benefiting from the unique 3D hierarchical porous architecture, preeminent conductivity, high specific surface area, efficient mass/charge transfer and synergic effect of various transition metals, the well-designed CoNiP/CoNiFeP@NCNFs exhibit extraordinary electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. Particularly, this novel material can work as a bifunctional catalyst in an integrated water-splitting electrolyzer, which only requires a low voltage of 1.55 V to realize the current density of 10 mA cm−2 with admirable durability (at least 28 h). This work certified the foreground of composites assembled by 3D hierarchical porous carbon and polymetallic phosphides for overall water splitting. It also provided a novel proposal for the rational designing and constructing highly active electrocatalysts by using coordination polymer and LDH as dual-precursors.

In–situ growth of flake SnS in three–dimensional hierarchical porous carbon boosting lithium storage performance

As a kind of superior performance anode material for lithium–ion batteries (LIBs), tin sulfide (SnS) still faces pressing issues such as conspicuous volume expansion and inferior rate performance in the reaction process. To effectively improve such pressing issues, this study presents a three–dimensional (3D) hierarchical porous carbon (HPC) and subtly takes flake SnS growing in situ on it. The 3D HPC has excellent interconnected porosity and different diameters of aperture, which play the role of bicontinuous transport of electrons and ions, and comprehensively improve the SnS electrochemical performance. In particular, the SnS@HPC anode delivers an excellent discharge capacity of 917.6 mAh g−1 after 100 cycles at 0.1 A g−1 current density and maintains a cycling stability with 500.7 mAh g−1 after 500 cycles at 2 A g−1 current density. More importantly, SnS@HPC||LiFePO4 full–cells also have excellent rate performance and cycling stability.

Bismuth-Antimony Alloy Nanoparticles Embedded in 3D Hierarchical Porous Carbon Skeleton Film for Superior Sodium Storage.

A composite film that features bismuth-antimony alloy nanoparticles uniformly embedded in a 3D hierarchical porous carbon skeleton is synthesized by the polyacrylonitrile-spreading method. The dissolved polystyrene is used as a soft template. The average diameter of the bismuth-antimony alloy nanoparticles is ~34.5 nm. The content of the Bi-Sb alloy has an impact on the electrochemical performance of the composite film. When the content of the bismuth-antimony alloy is 45.27%, the reversible capacity and cycling stability of the composite film are the best. Importantly, the composite film outperforms the bismuth-antimony alloy nanoparticles embedded in dense carbon film and the cube carbon nanobox in terms of specific capacity, cycling stability, and rate capability. The composite film can provide a discharge capacity of 322 mAh g-1 after 500 cycles at 0.5 A g-1, 292 mAh g-1 after 500 cycles at 1 A g-1, and 185 mAh g-1 after 2000 cycles at 10 A g-1. The carbon film prepared by the spreading method presents a unique integrated composite structure that significantly improves the structural stability and electronic conductivity of Bi-Sb alloy nanoparticles. The 3D hierarchical porous carbon skeleton structure further enhances electrolyte accessibility, promotes Na+ transport, increases reaction kinetics, and buffers internal stress.

CuxS particles loaded on S-doped 3D hierarchical porous carbon as an efficient electrode for superior asymmetric supercapacitors

CuxS particles loaded on S-doped 3D hierarchical porous carbon as an efficient electrode for superior asymmetric supercapacitors

In Situ Mineralization of Biomass‐Derived Hydrogels Boosts Capacitive Electrochemical Energy Storage in Free‐Standing 3D Carbon Aerogels

Here, a novel fabrication method for making free‐standing 3D hierarchical porous carbon aerogels from molecularly engineered biomass‐derived hydrogels is presented. In situ formed flower‐like CaCO3 molecularly embedded within the hydrogel network regulated the pore structure during in situ mineralization assisted one‐step activation graphitization (iMAG), while the intrinsic structural integrity of the carbon aerogels was maintained. The homogenously distributed minerals simultaneously acted as a hard template, activating agent, and graphitization catalyst. The decomposition of the homogenously distributed CaCO3 during iMAG followed by the etching of residual CaO through a mild acid washing endowed a robust carbon aerogel with high porosity and excellent electrochemical performance. At 0.5 mA cm−2, the gravimetric capacitance increased from 0.01 F g−1 without mineralization to 322 F g−1 with iMAG, which exceeds values reported for any other free‐standing or powder‐based biomass‐derived carbon electrodes. An outstanding cycling stability of ~104% after 1000 cycles in 1 M HClO4 was demonstrated. The assembled symmetric supercapacitor device delivered a high specific capacitance of 376 F g−1 and a high energy density of 26 W h kg−1 at a power density of 4000 W kg−1, with excellent cycling performance (98.5% retention after 2000 cycles). In combination with the proposed 3D printed mold‐assisted solution casting (3DMASC), iMAG allows for the generation of free‐standing carbon aerogel architectures with arbitrary shapes. Furthermore, the novel method introduces flexibility in constructing free‐standing carbon aerogels from any ionically cross‐linkable biopolymer while maintaining the ability to tailor the design, dimensions, and pore size distribution for specific energy storage applications.

One-step strategy of 3D hierarchical porous carbon with self-heteroatom-doped derived bread waste for high-performance supercapacitor

Bio-waste is a promising carbon source that can be used as a basic component in renewable supercapacitors due to its abundant hierarchical pore structure potential, heteroatom self-doping capability, high surface area, as well as well-defined chemical and mechanical stability. This study converted bread bio-waste into rich 3D hierarchical porous carbon through a one-step facile strategy to be used as the main component of a supercapacitor. The porous carbon was obtained through physical activation approach at different temperatures of 750, 800, 850, and 900 °C without being combined with chemical activation. The optimized activated carbon illustrated high porosity behavior with an abundant 3D hierarchical pore structure consisting of 76.98% micropores and 23.02% mesopores and also produced a well-defined wettability of self-doping heteroatoms. Moreover, the electrochemical behavior in a symmetric supercapacitor cell showed a high specific capacitance of 202 F g−1 at 1 A g−1 with a rate capability of 73% at 10 mV s−1 in a 1 M H2SO4 electrolyte. It was also discovered that the activation temperature of 850 produced the highest energy density of 11.61 Wh kg−1 at a power density of 156.71 W kg−1 with a low equivalent series resistance of 0.11 Ω. Finally, the proof-of-concept showed that bread waste has immense potential as a 3D hierarchical porous carbon source after the synthesis through a single-stage facile approach and can be used as a major renewable electrode component for sustainable supercapacitors.

Synergistic effect of nitrogen and oxygen dopants in 3D hierarchical porous carbon cathodes for ultra-fast zinc ion hybrid supercapacitors

Zinc-ion hybrid supercapacitor is one of the most promising electrochemical energy storage devices for the applications needing both high energy densities and power densities. Nitrogen doping is an effective way to enhance the capacitive performance of porous carbon cathodes in zinc-ion hybrid supercapacitor. However, accurate evidence is yet needed to demonstrate how nitrogen dopants influence the charge storage of Zn2+ and H+ cations. Herein, we prepared 3D interconnected hierarchical porous carbon nanosheets by a one-step explosion method. The effect of nitrogen dopants on pseudocapacitance was analyzed by the electrochemical behaviors of as-prepared porous carbon samples with similar morphology and pore structure but different nitrogen and oxygen doping levels. Ex–situ XPS and DFT calculation demonstrate that nitrogen dopants promote the pseudocapacitive reactions by lowering the energy barrier for the change of oxidation states of carbonyl moieties. Owing to the improved pseudocapacitance by nitrogen/oxygen dopants and fast diffusion of Zn2+ ions in 3D interconnected hierarchical porous carbon matrix, the as-constructed ZIHCs show both high gravimetric capacitance (301 F g−1 at 0.1 A g−1) and excellent rate capability (a capacitance retention of 30% at 200 A g−1).

NiCo2S4 combined 3D hierarchical porous carbon derived from lignin for high-performance supercapacitors

Metal sulfides with the nature of low electronegativity and high electrochemical activity are potentially considered effective electrode materials for supercapacitors. Meanwhile, hierarchical porous carbon (HPC) materials derived from eco-friendly enzymatic hydrolysis lignin are the ideal matrix for holding nanoparticles (NP) that allows the overall NP/HPC composite to achieve outstanding electrochemical performance. In this study, NiCo2S4 nanoparticles were in-situ synthesized on the inner surface of 3D HPC that derived from enzymatic hydrolysis lignin with a simple one-step solvothermal method, thus forming a high-performance composite electrode material for supercapacitor applications. As a result, the NiCo2S4/HPC composite yields an outstanding specific capacity of 1264.2 F g−1 at 1 A g−1 and also exhibits remarkable rate performance. Such remarkable property is attributed to the effective combination of NiCo2S4 plus HPC and their strong chemical bonds, which enable excellent electronic conductivity and abundant exposed electroactive sites. The asymmetric supercapacitor assembled by utilizing NiCo2S4/HPC and active carbon as the positive and negative electrodes, respectively, provide an excellent energy density of 32.05 Wh kg−1 at a power density of 193.9 W kg−1. This work puts forward a practical optimization strategy for metal sulfides used in electrochemical energy storage devices.

Biomass-Derived Porous Carbon: Synthesis and Application for Energy Conversion and Storage

The conversion of biomass to carbonaceous materials have received wide attention these years. In particular, biomass-derived carbons demonstrate great potential as electrodes for different energy storage system due to their various architectures, low cost, and renewability. This review provided the recent progress in the synthesis and application of biomass-derived carbons and their hybrids as electrodes for energy storage. Various carbon structures including spheres, 1D fiber/tube, 2D sheets, 3D hierarchical porous carbon have been acquired from various biomass through different activation methods. Owing to their devise composition and morphology, the biomass-derived carbon materials are employed as electrodes for supercapacitors, metal-ion batteries and Li-S batteries. Finally, conclusions and outlook trends to the future development of biomass-derived carbons are proposed.

3D hierarchical tri-doped porous carbon derived from calcium lignosulfonate for high-performance zinc ion hybrid capacitors

Low-cost calcium lignosulfonate (CLS) as a carbon source was used to prepare N, O, and S tri-doped hierarchical porous carbon (LHPC) electrode material by a one-step carbonization method without additional pore-forming agents.

Single-Atom Vanadium Catalyst Boosting Reaction Kinetics of Polysulfides in Na-S Batteries.

The practical application of the room-temperature sodium-sulfur (RT Na-S) batteries is hindered by the insulated sulfur, the severe shuttle effect of sodium polysulfides, and insufficient polysulfide conversion. Herein, on the basis of first principles calculations, single-atom vanadium anchored on a 3Dnitrogen-doped hierarchical porous carbon matrix (denoted as 3D-PNCV) is designed and fabricated to enhance sulfur reactivity, and adsorption and catalytic conversion performance of sodium polysulfide. The 3D-PNCV host with abundant and active V sites, hierarchical porous structure, high electrical conductivity, and strong chemical adsorption/conversion ability of V-N bonding can immobilize the polysulfides and promote reversibly catalytic conversion of polysulfides toward Na2 S. Therefore, as-fabricated RT Na-S batteries can achieve a high reversible capacity (445mAhg-1 over 800 cycles at 5Ag-1 ) and excellent rate capability (224mAhg-1 at 10Ag-1 ). The electrocatalysis mechanism of sodium polysulfides is further experimentally and theoretically revealed, which provides a new strategy to develop the highly stable RT Na-S batteries.

Efficient conversion of biomass waste to N/O co-doped hierarchical porous carbon for high performance supercapacitors

Aiming at the double carbon goals, the transfer of biomass waste to high value-added products for energy conversion and storage is strongly required. Herein, a N/O co-doped 3D hierarchical porous carbon is fabricated via an efficient KOH-assisted protocol to convert orange peels into high performance carbon-based electrode for supercapacitor application. KOH not only creates porous structure for high surface area, but also exposes the intrinsic nitrogen source buried in biomass for structural N-doping. Consequently, the resultant carbon possessed a hierarchical architecture with interconnected multiscale vacancies and optimized pore size distribution, together with a beneficial co-doping of N and O heteroatoms, thereby contributing to an intense surface entrapment, short ion transportation distance, fast mass transportation and sturdy skeleton. Gratifyingly, it is demonstrated as a satisfactory electrode for supercapacitor with excellent specific capacitance of 352 F g-1 at 0.5 A g-1, attractive rate capability of 71.6% capacitance retention at a 100-fold higher current density and superior cycling stability of only 0.5% loss in capacitance reservation after 10,000 cycles at an ultrahigh current density of 50 A g-1. By taking advantage of the inherent composition and structure of biomass, the conversion of orange peels to advanced carbon-based electrode materials open up a brand-new bioinspired design of structural doping functional carbon towards the field of energy storage.

Hierarchical and lamellar porous carbon as interconnected sulfur host and polysulfide-proof interlayer for Li–S batteries

A robust three-dimensional (3D) interconnected sulfur host and a polysulfide-proof interlayer are key components in high-performance Li–S batteries. Herein, cellulose-based 3D hierarchical porous carbon (HPC) and two-dimensional (2D) lamellar porous carbon (LPC) are employed as the sulfur host and polysulfide-proof interlayer, respectively, for a Li–S battery. The 3D HPC displays a cross-linked macroporous structure, which allows high sulfur loading and restriction capability and provides unobstructed electrolyte diffusion channels. With a stackable carbon sheet of 2D LPC that has a large plane view size and is ultrathin and porous, the LPC-coated separator effectively inhibits polysulfides. An optimized combination of the HPC and LPC yields an electrode structure that effectively protects the lithium anode against corrosion by polysulfides, giving the cell a high capacity of 1339.4 mAh g−1 and high stability, with a capacity decay rate of 0.021% per cycle at 0.2C. This work provides a new understanding of biomaterials and offers a novel strategy to improve the performance of Li–S batteries for practical applications.

3D Hierarchical Porous Carbon Aerogel Electrocatalysts Based on Cellulose/Aramid Nanofibers and Application in High-Performance Zn–Air Batteries

Three-dimensional (3D) carbon aerogels (CAs) are composed of interconnected networks and emerge as appealing platforms for the combination of heteroatom dopants, defective sites, and hierarchical porous structures. Here, we propose an effective and sustainable strategy to construct TOCNF/ANF-Cd hydrogels/aerogels using TEMPO-oxidized cellulose nanofibers (TOCNFs), thermally stabilized aramid nanofibers (ANFs), and low-boiling-point Cd2+. Hierarchical porous N-doped aerogel catalysts (N/CA-Cd) with TOCNF/ANF synergistic cross-linking were obtained by moderate temperature pyrolysis. Apart from serving as a source of N, ANF also improves carbon retention and graphitization, increasing the electrical conductivity of carbon aerogels. Due to the spatially continuous structure and multiscale porous structure and abundant N dopants and edges/defects, the as-obtained N/CA0.5-Cd carbonaceous catalysts manifest an impressive electrocatalytic efficacy with a positive half-wave potential (0.86 V). In particular, the Zn–air batteries assembled with N/CA0.5-Cd as the air cathode catalyst have an excellent peak power density of 186 mW cm–2 and a splendid specific capacity of 730 mA h g–1.

From whey robocasting to custom 3D porous carbons

We describe how robocasting and carbonisation of partially dehydrated whey, a surplus of the dairy industry, produced 3D porous carbons with custom morphologies. A relatively simple printing device was first used to manufacture 3D structures of whey pastes. The whey pastes behaved as a thermoset polymer when heated hence keeping the original shape of the printed pieces upon carbonisation, albeit an isotropic size reduction (23%) due to thermal shrinkage. The rheological properties of the whey pastes were similar to those of other inks commonly used in direct ink writing, with a shear thinning behaviour and static and dynamic yield stresses that predicted their printability in most robocasting devices. Once the 3D whey structures were printed, a heat-curing process was required to avoid the uncontrolled emission of volatiles that would otherwise distort them. When doing so, 3D lattices of carbon filaments with ca. 500 µm in diameter and ca. 425 µm mesh size were manufactured. The ash content of the carbonised structures, which is related to the salt content of the original whey, was reduced by conventional washing procedures, bringing about 3D hierarchical porous carbons (70% porosity) with modest specific surface areas (500 m 2 /g) and relatively high compressive strengths (5 MPa). • Whey/water pastes can be printed using 3D extrusion printers. • Carbonisation of printed pieces preserves their shape (albeit thermal shrinkage). • 3D carbon pieces combine good mechanical properties and high porosities.