High-performance Porous Carbon Research Articles

Preparation of nanodiamonds modified hard carbon with uniform spherical feature for improving sodium-ion storage performances

Sodium-ion batteries (SIBs) have received remarkable attention due to their abundant sodium (Na) content and low resources cost. However, the absence of high-performance anode materials make carbon-based SIBs still a challenge. Herein, nano-diamonds (NDs) modified gleditsia japonica shell carbon to form a uniform carbon microsphere, which improves the graphitization degree and Na ion adsorption, NDs also act as a strong scaffold to maintain its stability. This spherical carbon-based material exhibits superior performances including the enhanced capacity (270 mA h g−1 at 0.2C after 100 cycles) and long-cycle stability (155 mA h g−1 at 2C after 1000 cycles) when incorporated into SIBs. This work provides a green and simple synthesis strategy for fabricating high performance porous spherical carbon used for SIBs anode.

Sustainable Green Route for Activated Carbon Synthesis from Biomass Waste for High-Performance Supercapacitors.

Supercapacitors are high-power energy storage devices due to their charge storage capability and long cyclic stability. These devices rely on highly porous materials for electrodes providing a substantial surface area per mass, such as highly porous carbon. Developing high-performance porous carbon from biomass wastes such as waste-activated sludge and spent coffee is a sustainable way to reduce adverse environmental effects, contributing toward a carbon circular economy. In this study, hierarchically porous carbon with a high surface area of 1198 ± 60 m2 g-1 was synthesized through a green route. Sodium acetate was utilized as an environmentally friendly electrolyte. The long-term stability test at a high current density was conducted, providing valuable insights into the viability of sodium acetate as a robust electrolyte in supercapacitor application. The supercapacitor demonstrated an excellent cycle stability of 98.4% after 20,000 cycles at a current density of 10 A g-1 in sodium acetate. Further assessment revealed dominant fast surface kinetics. Moreover, a maximum energy density of 15.9 Wh kg-1 at 0.2 A g-1 was achieved. By utilizing highly porous carbon in conjunction with a water-based binder, a substantial improvement of 76% in capacity with respect to a nonaqueous-based binder was demonstrated.

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.

Chinese baijiu spent grains-based high-performance porous hard carbon for sodium-ion battery anodes

Chinese baijiu spent grains-based high-performance porous hard carbon for sodium-ion battery anodes

Porous carbon derived from a by-product of traditional Chinese medicine for high-performance aqueous zinc-ion hybrid supercapacitors

The rational utilization of biomass waste for the production of usable energy holds immense significance. The present study proposes the effective utilization of a byproduct derived from traditional Chinese medicine, specifically momordica grosvenori shell, as a precursor for fabricating high-performance porous carbon electrodes in rechargeable aqueous zinc ion supercapacitors. The MGCx-T electrodes are prepared by KOH activation and carbonization with MG (momordica grosvenori shell). The influence of KOH addition amount and carbonization temperature on the properties of the prepared materials were studied. Resulting that MGC3–800 has good electrical conductivity, high specific surface area (1141 m2 g−1) and abundant pore structure. The maximum specific capacity reaches 228.7 mAh g−1 at 0.2 A g−1 in 2 M ZnSO4 electrolyte. In the gelatin/ZnSO4 electrolyte, the specific capacity reaches a maximum of 186.1 mAh g−1. Additionally, it exhibits an energy density of 167.5 Wh kg−1 and a power density of 6300 W kg−1. Furthermore, exceptional cycling stability is observed with a capacity retention rate of 92.6 % after 10,000 cycles. Hence, the realization of an industry-effective strategy that not only utilizes biomass waste, but also produces high-performance zinc-ion hybrid supercapacitor electrodes has been achieved.

Coal tar pitch-derived porous carbon prepared in deep eutectic spinning solution via electrospinning for supercapacitor electrodes

Developing a novel preparation strategy for the fabrication of high-performance porous carbon electrode materials is still the focus of current research. Herein, O/N doped coal tar pitch (CTP)-based porous carbon with a fishnet-like structure is prepared via the electrospinning technology. CTP is used as a carbon source and ChCl/phenol deep eutectic solvent (DES) is used as a spinning solution directly, and not any polymer is added. The complexes obtained by electrospinning are then activated by a small amount of K3C6H5O7 and get the porous carbon. Specifically, the DES has a specific viscosity and can be used not only as a solvent to improve the spinnability of CTP, but also as N source and act as a multifunctional solution. The electrospinning technology constructs the macropores and mesopores, while K3C6H5O7 can make micropores and even ultra-micropores in the prepared carbon material. Benefiting from the constructive hierarchical pore channels and abundant heteroatoms doping, the prepared porous carbon electrode possesses a high specific capacitance of 202 F g−1 even when reaching commercial loading. Simultaneously, a novel K3C6H5O7/glycol/acetonitrile DES gel electrolyte is synthesized, and an extended working voltage (2.2 V) can be achieved. The fabricated capacitor has large energy density of 23.9 Wh kg−1, and can still operate normally in a wide temperature range (-25 ∼ 100 °C). The multifunctionality of DES uncovers the feasibility of preparation of porous carbon using DES as the spinning solution directly, and may expect to prepare other carbon materials using the proposed strategy with different carbon precursors.

Preparation of high-performance nitrogen doped porous carbon from cork biomass by K2CO3 activation for adsorption of rhodamine B

Biomass waste, an attractive renewable carbon source, has great potential for carbon reduction. In recent years, high-performance porous carbon materials prepared from agricultural and forestry waste have demonstrated significant promise for applications in the field of dye wastewater purification. In this study, cork waste from Quercus variabilis was utilized as a raw material, melamine as a nitrogen source, and K2CO3 as a green activator to prepare nitrogen-doped porous cork activated carbon (NCAC) with a honeycomb structure. The results showed that NCAC-900, activated at 900 °C, exhibited a highly porous structure with an optimal specific surface area of 2051.35 m2/g and a pore volume of 1.18 cm3/g. To evaluate its adsorption performance towards rhodamine B (RhB), collaborative activation and post-treatment were employed to enhance the adsorption capacity of the dyes. NCAC-900 demonstrated excellent removal efficiency, with a theoretical maximum adsorption capacity of 2552.52 mg/g (at an adsorbent dosage of 0.2 g/L) in a 300 mg/L solution. Nitrogen doping effectively improved the adsorption capacity for RhB, fitting well to the quasi-secondary kinetic model (R2 = 0.9973–0.9999) and Langmuir isotherm (R2 = 0.7697–0.9523) for the adsorption kinetics and equilibrium data. A comparison with the existing literature also revealed that NCAC-900 possessed a remarkably fast adsorption rate of 12.82 mg/g/min. Moreover, the resorption efficiency of NCAC-900 for RhB reached approximately 66.78% after five consecutive adsorption-desorption cycles. Additionally, the obtained nitrogen-doped cork activated carbon exhibited impressive adsorption capabilities of anionic dye Congo red (CR, qm=1499.14 mg/g) and cationic dye methylene blue (MB, qm=571.54 mg/g). In conclusion, our work presented a promising method for preparing excellent NCAC as an efficient adsorbent for wastewater dyes, offering new ideas and theoretical foundations for the high-value utilization of cork materials and the development of cork activated carbon.

Electrochemical properties of porous carbon derived from coal gasification fine ash via low-temperature alkaline fusion and KOH activation

Coal gasification fine ash (a carbon-based solid waste, CGFA) is regarded as the ideal precursors for constructing carbon-based porous materials due to their low cost, high yield, high carbon content, and abundant pore structure. This study employed CGFA as the raw material and prepared porous carbon samples with a high specific surface area (SBET) of 2167.5 m2/g and a high mesoporous ratio of 80.1 % (by volume) using an low-temperature alkaline fusion-KOH activation method. The sample exhibited ideal double-layer capacitance behavior with a mass-specific capacitance of 219.7 F/g (at 1 A/g) and a capacitance retention rate of 82.6 % (at 1 A/g–20 A/g). The energy density of the assembled symmetrical supercapacitor was 13.4 Wh/kg (corresponding to a power density of 475 W/kg), and the capacitance retention rate was 97.9 % after 15,000 cycles. In summary, this work prepared high-performance porous carbon for supercapacitors from widely existing industrial waste CGFA, which provides a feasible strategy for the application of CGFA derived porous carbon in energy storage materials.

Imine-linked polymer derived N-Doped microporous carbons in PEO-based mixed matrix membranes for enhanced CO2/N2 separation: A comparative study

Imine-linked porous organic polymers (POPs) have attracted much attention in gas separation due to their high porosity and adjustable structure, and they are great potential candidates for nitrogen-doped porous carbons for CO2/N2 separation in mixed matrix membranes (MMMs). In this work, we synthesized imine-linked POPs via a facile method and obtained their derived carbons N-CSs via carbonization under an inert atmosphere. We found that the textural structure and functional surface of N-CSs are well inherited and further developed due to the high thermal stability of N-POPs. Nitrogen-containing functional groups in N-POPs and N-CSs improved the interfacial compatibility between polymer and fillers via hydrogen bonds. The textural structure of N-CSs with abundant narrower ultra-micropores (0.53 nm), as well as high nitrogen functional groups (4.65 wt%), endows poly (ethylene oxide) (PEO) membranes with superior molecular sieving ability for CO2 over N2 and fast CO2 transport channels. For instance, MMMs with 2.0 wt% loading of N-CSs exhibit an admirable gas separation performance with CO2 permeability of 540.4 Barrer and CO2/N2 selectivity of 61.3, surpassing the Upper bound (2019). The long-term stability of both MMMs is explored, which shows great potential in practical CO2 capture applications. This strategy of carbonization of imine-linked porous polymers provides ideas for the preparation of high-performance porous carbon-based MMMs and carbon molecular sieve membranes (CMSMs).

Ultrafast carbothermal shock strategy enabled highly graphitic porous carbon supports for fuel cells

The electronic conductivity and durability of porous carbon supports can be improved by increasing the degree of graphitization in the material; however, the preparation of highly graphitic porous carbon using conventional furnaces remains a significant challenge. Herein, we demonstrate a universal and highly efficient carbothermal shock strategy that significantly improves the degree of graphitization of porous carbon supports, including bowl-like carbon, hollow carbon spheres, ZIF8-derived carbon, BP2000, and Ketjen EC 300J. Taking bowl-like carbon as an example, we illustrate the synthesis of a graphitized bowl-like carbon (G-BC-S) support and evaluate the performance of PtCo/G-BC-S in the oxygen reduction reaction (ORR) in rotating disk electrodes (RDE) and H2/air PEM single cells. PtCo/G-BC-S exhibits faster ORR kinetics than PtCo/BC and Pt/C, with little loss of activity (25%) and only 13 mV of E1/2 decay after 20000 cycles accelerated stress testing under 1.0–1.5 V vs. a reversible hydrogen electrode (RHE).</a> The significantly enhanced performance of the PtCo/G-BC-S catalyst arises from the high activity and chemical/structural stability of the PtCo intermetallic nanoparticles and from the high degree of graphitization and well-defined porous structure of the bowl-like carbon support, which confers excellent electrical conductivity and oxygen transport properties. This study provides a reliable and universal strategy for the development of high-performance porous carbon supports for practical applications in fuel cells.

High-Performance Porous Carbon Electrode Materials Derived from Air Pre-oxidation of Anthracite Supplemented with KOH Activation for Supercapacitors

High-Performance Porous Carbon Electrode Materials Derived from Air Pre-oxidation of Anthracite Supplemented with KOH Activation for Supercapacitors

Peanut shell waste derived porous carbon for high-performance supercapacitors

Low-cost and high-performance porous carbon electrode materials are the key to supercapacitors. Here, we reported the preparation of porous carbon materials by high-temperature carbonization coupled with chemical activators (H3PO4, ZnCl2, KOH) using peanut shell waste. The as-synthesized porous carbon with KOH as the chemical activator (KOH-AC) has the best ideal electric double-layer capacitance performance, outperforming other activator-treated porous carbon. In the three-electrode system, the prepared KOH-AC electrode material showed an ultra-high specific capacitance of 575.7 F g−1 at a current density of 0.5 A g−1, good rate characteristics and excellent electrochemical stability (106.5 % initial capacitance after 10,000 cycles), which exceeded that of most biomass carbon-based materials. In the two-electrode system with 6 M KOH as electrolyte, the symmetrical supercapacitor based on KOH-AC showed a high specific capacitance of 390.9 F g−1 at 0.5 A g−1 current density in the voltage rang of 0–1.3 V, with the maximum energy density of 22.2 Wh kg−1 and power density of 319.97 W kg−1 and excellent cycle stability (93.8 % after 10,000 cycles). In addition, it is also studied that all-solid-state flexible symmetric supercapacitor in PVA/KOH electrolyte shows a high specific capacitance of 432.7 F g−1 at 0.5 A g−1 current density and can provide energy density of 18.2 Wh kg−1 and power density of 275.3 W kg−1. In summary, this work synthesized high-performance porous carbon materials from renewable and sustainable biological wastes, which provided a feasible method for the application of biomass carbon in energy storage.

N-Doped Yolk–Shell Carbon Nanospheres with “Carbon Bridges” for Supercapacitors

N-doping multilocular carbon spheres are beneficial to improving the electrical property due to their unique pore structure and elemental composition; nevertheless, there is a great challenge to fabricate this structure in a facile way. In this work, an N-doping yolk–shell carbon nanosphere with a “carbon bridges” structure was prepared by domain-limited carbonization of RF@SiO2 (RF = resorcinol-formaldehyde resin) with ethylenediamine (EDA) as the nitrogen precursor. The structure of the “carbon bridges” and the carbon shell’s thickness can be adjusted by controlling the thickness of the silica layer, resulting in a change in morphology (from dense nanospheres to yolk–shell nanospheres). The optimized yolk–shell carbon nanospheres (C@C-2 nanospheres) exhibited high N-doping, an abundant micro-mesoporous structure, and an optimum “carbon bridges” structure, contributing to a high-rate capability in a supercapacitor, which was reflected in the energy storage dynamics. Herein, C@C-2 nanospheres, as an electrode material for supercapacitors, presented a reversible specific capacitance of 373.3 F g–1 at 0.5 A g–1 in 2 M KOH and retained a well-advanced capacitance retention capability (95.8%) at 4 A g–1 for more than 10,000 cycles. This work sheds light on an avenue to design high-performance porous carbons for efficient energy storage.

Dual-Salt-Induced Hierarchical Porous Structure in a Carbon Sheet for High Performance Supercapacitors

Porous carbon, one of the characteristic materials for electrochemical energy storage devices, has been paid wide-ranging attention. However, balancing the reconcilable mesopore volume with a large specific surface area (SSA) was still a challenge. Herein, a dual-salt-induced activation strategy was developed to obtain a porous carbon sheet with ultrahigh SSA (3082 m2 g-1), desirable mesopore volume (0.66 cm3 g-1), nanosheet morphology, and high surface O (7.87%) and S (4.0%) content. Hence, as a supercapacitor electrode, the optimal sample possessed a high specific capacitance (351 F g-1 at 1 A g-1) and excellent rate performance (holding capacitance up to 72.2% at 50 A g-1). Furthermore, the assembled zinc-ion hybrid supercapacitor also exhibited superior reversible capacity (142.7 mAh g-1 at 0.2 A g-1) and highly stable cycling (71.2 mAh g-1 at 5 A g-1 after 10,000 cycles with retention of 98.9%). This work was delivered a new possibility for the development of coal resources for the preparation of high performance porous carbon materials.

Explosive effect-assisted synthesis of hierarchical porous carbon for high-performance aqueous Zn-ion hybrid supercapacitors with commercial level mass loading

Aqueous Zn-ion hybrid supercapacitors (AZHCs) are potential types of energy storage applications that combine the advantages of supercapacitors and batteries. The low mass loading and poor rate performance of cathodes, however, severely limits their practical application. Herein, an explosive effect assisted strategy is reported for the efficient synthesis of N, O co-doped porous carbon nanosheets (NPCNs) by synergistic activation of high-quality soft carbon precursor perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) with KOH and Zn(NO3)2. Benefiting from the comprehensive modulation of the morphology, pore structure, and surface chemistry, the obtained NPCNs show the significant enhancement in diffusion kinetics. Consequently, the as-fabricated AZHCs exhibited remarkably improved Zn-ion storage capability (189.3 mAh g−1 at 0.1 A g−1, 96.7 mAh g−1 at 20 A g−1) and long-term cycling stability at 20 A g−1 (∼ 92.5 % retention upon 6000 cycles). Moreover, NPCNs also deliver a superb areal capacity of 1.6 mAh cm−2 with a mass loading of 15.4 mg cm−2. Most importantly, we demonstrate that such porous carbon framework with competent electrochemical properties can be easily produced from diverse soft carbon precursor. This work thus introduces a universal and efficient strategy to produce high-performance porous carbon electrode materials for AZHCs.

Lignin derived porous carbon with favorable mesoporous contributions for highly efficient ionic liquid-based supercapacitors

Lignin and its derivatives hold great potential in developing high performance porous carbon materials for supercapacitors due to the versatile features of high carbon content, abundant multifunctional groups, low cost, and environmental benefits. Unfortunately, their derived porous carbon generally has the features of unfavorable microporous-dominated morphologies and low specific surface area (SSA) attributed from the highly-branched structure of lignin, which are hardly suitable for the supercapacitors with ionic liquid (IL) electrolyte, leading to poor energy density and rate capability. Herein, porous carbon materials with desirable mesoporous contributions from sodium lignosulphonate are designed via a facile template method. Such rich mesoporisity carbon materials not only possess with three-dimensional interconnected network, large SSA, as well as favorable pore size distribution for accelerated ion and electron mass transfer, but also feature low heteroatom content for high electrochemical stability. Consequently, the optimal electrode exhibits a high capacitance of 166 F/g at 0.5 A/g, superior rate performance (59 Wh/kg at 59 kW/kg), as well as impressive cycle life with good capacitance retention of 93.1% in EMIBF4 electrolytes. The present work opens a new avenue to design porous carbon materials with high mesopore properties from lignin for effective compatibility with IL electrolyte in high-performance supercapacitors.

Preparation of high performance porous carbon by microwave synergistic nitrogen/phosphorus doping for efficient removal of Cu2+ via capacitive deionization

Sargassum biochar has potential advantages as an electrode material due to its natural microscopic pore channels. However, conventional pyrolysis method is prone to thermal damage to the biochar, and incapable to form a complete pore structure resulting in poor biochar electrode performance. In this study, a strategy of microwave pyrolysis coupled with KOH activation was used to prepare nitrogen/phosphorus double-doped graded porous biochar (STC) using ammonium dihydrogen phosphate as dopant. The carbon material STC-1.24-800 prepared by the optimal parameters had a high specific surface area (SSA) of 1367.6 m2 g −1 and a total pore volume of 1.499 cm3 g−1. The precise inside-out heating characteristics of microwave facilitated the generation of suitable meso-micropore distribution ratios in carbon, and the graded porous structure provided abundant active sites for charge accumulation and ion diffusion. The doped nitrogen/phosphorus atoms responding to the microwave field, generated spin to promote microwave absorption, introducing surface structural defects to produce electron density differences. The change in the nature of the electron donor and its electron density enhanced the electrical conductivity and chemical stability of STC. Nitrogen/phosphorus polar surface functional groups improved hydrophilicity and wettability. STC-1.24-800 had a higher specific capacitance of 531 F g−1 and exhibits great cycle performance in capacitive deionization (CDI) applications (1.0 V, 50 mg L−1 Cu2+) as well as adsorption performance (56.16 mg g −1). The present work can provide a novel feasible idea for preparing diatomically doped graded porous biochar for CDI electrode application by microwave irradiation.

Sweet-Potato-Vine-Based High-Performance Porous Carbon for Methylene Blue Adsorption.

In this study, sweet-potato-vine-based porous carbon (SPVPC) was prepared using zinc chloride as an activating and pore-forming agent. The optimised SPVPC exhibited abundant porous structures with a high specific surface area of 1397.8 m2 g-1. Moreover, SPVPC exhibited excellent adsorption characteristics for removing methylene blue (MB) from aqueous solutions. The maximum adsorption capacity for MB reached 653.6 mg g-1, and the reusability was satisfactory. The adsorption kinetics and isotherm were in good agreement with the pseudo-second-order kinetics and Langmuir models, respectively. The adsorption mechanism was summarised as the synergistic effects of the hierarchically porous structures in SPVPC and various interactions between SPVPC and MB. Considering its low cost and excellent adsorption performance, the prepared porous carbon is a promising adsorbent candidate for dye wastewater treatment.

Explainable machine learning for carbon dioxide adsorption on porous carbon

The ever-increasing carbon emission requires the development of advanced carbon capture and storage technology. As one of the most promising approaches, the adsorption of CO2 over porous carbon (PC) has been intensively studied due to the low cost, easy synthesis, and high adsorption capacity of PC. However, further improvement in its CO2 adsorption capacity is hindered by the unclear relationship between each physicochemical property and the adsorption capacity. Recently machine learning (ML) has achieved giant progress in predicting the adsorption capacity of PCs. However, due to the intrinsic “black box” property of ML, the quantitative relationship between each physicochemical property and corresponding adsorption capacity cannot be derived. Herein, first random forest was well trained to predict the CO2 adsorption capacity. Then, Shapley Additive Explanations, a powerful visualization tool, was adopted to provide insights into such an uncovered relationship. The results showed that textural property is more important than chemical composition in affecting CO2 uptake. Furthermore, SHAP indicated that high CO2 adsorption capacity appeared at low pressure, temperature of 298 K with specific surface area of 1100–1300 m2/g, micropore volume of 0.4–0.6 cm3/g, mesopore volume of < 0.1 cm2/g, carbon of 72–86 wt%, hydrogen of 1–4 wt%, oxygen of < 16 wt%, and nitrogen of < 1 wt%. This study sheds light on the understanding of the CO2 adsorption mechanism on PC and guides the design of next-generation high-performance PC for carbon capture and storage.

Self-doped N, S porous carbon from semi-coking wastewater-based phenolic resin for supercapacitor electrodes.

Contamination of phenolic compounds has devastating effects on the environment. Therefore, its harmless treatment and recycling have received extensive attention. Herein, a novel method for preparing N-S doped phenolic resin (NSPR) from phenols, N and S groups in semi-coking wastewater, and formaldehyde are developed. The KOH is consequently incorporated into the NSPR through simultaneous carbonization and activation in a single step to produce porous carbon material (NSPC). The as-obtained NSPC exhibits a high specific capacitance of 182 F g−1 at 0.5 A g−1, a high energy density of 9.1 Wh kg−1 at a power density of 0.15 kW kg−1, and remarkable cycling stability in aqueous KOH electrolyte. This outstanding electrochemical performance is attributed to its ultrahigh specific surface area (SSA, 2,523 m2 g−1), enormous total pore volume (Vt, 1.30 cm3 g−1), rational pore structure, and N-S heteroatom self-doping (0.76 at% N and 0.914 at% S), which ensures adequate charge storage, rapid electrolyte ion diffusion, and contributed pseudo-capacitance. This work not only provides a facile method for transforming phenolic wastewater into high-value products but also offers a cost-effective and high-performance porous carbon material for supercapacitors.