Ketjen Black Research Articles

A novel sandwich-type electrochemical immunosensor for sensitive detection of zearalenone using NG/PDDA/HNTs and Ti-MOF-KB composites for signal amplification

In this work, a novel sandwich-type electrochemical immunosensor based on signal amplification was developed for the ultrasensitive detection of zearalenone (ZEA). The composite consisting of poly(diallyldimethylammonium chloride) functionalized nitrogen doped graphene, halloysite nanotubes and toluidine blue (Tb/NG/PDDA/HNTs), was synthesized for the first time. Then it was modified with gold nanoparticles (AuNPs) to bind the secondary antibody (Ab2, 10 μg mL−1) and form the tracer label. In addition, ketjen black (KB) was doped into titanium-based metal–organic framework (Ti-MOF), which provided large specific surface area and employed as the sensing platform to increase the immobilization of the primary antibody (Ab1, 10 μg mL−1). This immunosensor showed a wide linear range for ZEA from 10 fg mL−1 to 100 ng mL−1 with a limit of detection (LOD) as low as 0.57 fg mL−1, which was below the maximum tolerable levels (50∼100 µg kg−1) set by the United Nations Food and Agriculture Organization (FAO).

Development of Non-Spherical Platinum Nanoparticles on Carbon Supports for Oxygen Reduction Reaction

Proton exchange membrane fuel cells are anticipated to play an important role in decarbonizing the global energy system, but the performance of platinum (Pt) catalysts must be improved to make this technology more economical. Studies have identified non-spherical Pt nanoparticles on carbon supports as promising approaches to address this challenge. However, to realize the full benefits of these strategies, the catalyst synthesis procedures must be successfully simplified and scaled up, and the catalyst must perform well in half and full-cell tests. In this study, a surfactant-free one-pot method is developed to synthesize non-spherical Pt nanoparticles on Ketjen Black carbon, which is either non-treated (Pt/KB), acid-treated (Pt/KB-O), or nitrogen-doped (Pt/KB-N). The catalysts are synthesized in both small and large batches to determine the effect of scaling up the synthesis procedure. The nitrogen-doped carbon support shows a nearly identical morphological structure with uniform distribution of non-spherical Pt nanoparticles for both small and large batches’ synthesis compared with non-treated and acid-treated carbon samples. The comparative oxygen reduction reaction (ORR) activity shows that the Pt/KB-N prepared in small and large batches has better ORR activity, which is likely caused by uniformly distributed non-spherical Pt nanoparticles on the nitrogen-doped carbon support. All three catalysts show similar ORR durability, testing from 0.5–1.0 V, while Pt/KB-O displays slightly better durability from 1.0–1.5 V for carbon corrosion. These results will help inform the implementation of shape-controlled Pt catalysts on modified carbon supports in large scale.

Low temperature and rapid synthesis of nitrogen-doped carbon-based catalysts via atmospheric pressure plasma

Nitrogen-doped carbon materials have attracted significant attention as promising non-metal electrochemical catalysts for oxygen reduction reaction. The commonly used chemical synthesis methods which usually necessitate prolonged elevated-temperature sintering are unsuitable for thermally sensitive catalysts. Generally, these methods require a long duration of gas infiltration and the involvement of toxic chemical reagents. These factors make it difficult to maintain sample consistency during the preparation process. In this paper, a low-temperature synthesis approach is introduced to prepare nitrogen-doped carbon-based catalysts using Ar surface dielectric barrier discharge to treat a mixed precursor of Ketjen Black and ammonium carbonate at atmospheric pressure. The obtained catalysts exhibit moderate defects and successful nitrogen doping. Compared with catalysts prepared using traditional chemical methods, they show superior electrochemical performance. The limiting current density has exhibited performance superior to commercial Pt/C catalysts, as well as higher stability and methanol tolerance. Furthermore, the mechanism of nitrogen doping achieved through plasma treat chemical bonds is explained. This work proposes a feasible strategy for synthesizing nitrogen-doped carbon materials and tuning catalyst performance, and provides deep insights into the plasma regulation of catalysts.

Na4MnCr(PO4)3 with a Dual Conductive Network for Sodium‐Ion Batteries

AbstractNASICON (NAtrium Super Ionic CONductor)‐structured Na4MnCr(PO4)3 has attracted attention as a promising cathode for sodium‐ion batteries due to its high operating voltage and specific capacity contributed by multielectron reactions. Unfortunately, its intrinsic low electronic conductivity significantly hinders the release of specific capacity and rate capability, preventing its practical application. Herein, a carbon layer with dual conductive networks connected by chain‐like Ketjen black (KB) is built on the surface of Na4MnCr(PO4)3 material. This novel Na4MnCr(PO4)3/C@KB composite material exhibits improved rate capability of 61.2 mAh g−1 at 2 C compared to 19.5 mAh g−1 of Na4MnCr(PO4)3/C and high reversible capacity of 88.0 mAh g−1 at 1 C with 73% capacity retention after 100 cycles. The enhanced electrochemical performance can be ascribed to an increase of electronic conductivity enabled by the dual conductive 3D network construction and an adequate infiltration of electrolyte by substantial pores existence in carbon layer. A promising dual conductive network design strategy is demonstrated here for improving the performance of NASICON‐structured cathodes.

Enhancing the cycle life of rechargeable Zn-air batteries via in-situ growth FeNi layered double hydroxide on Co3O4 air electrode

As a promising secondary battery, the short cycle life of Zn-air batteries (ZABs) severely limits their further application. The traditional air electrode could not maximize the OER activity of air electrode due to the existence of multiphase interface. In this work, FeNi layered double hydroxide (FeNi-LDH) without further hydrophobic treatment as main OER catalyst was in-situ grown on the initial Co3O4 air electrode (Ketjen Black as conductive carbon) surface by electrochemical deposition method. With a FeNi-LDH as main OER active component, assembled ZABs delivered an enhance cycle life of 38.1 h, 3.15 times than initial Co3O4 air electrode (12.1 h). The significant increase in cycle life is mainly due to the lower charging voltage caused by the FeNi-LDH layer with better OER catalytic activity than Co3O4, which reduces the ORR site inactivation and carbon oxidation rate. Therefore, after using multiwalled carbon nanotubes with better oxidation resistance as the conductive carbon instead of Ketjen Black and increasing the mass loading of Co3O4 air electrode from 2.0 to 4.0 mg cm−2, the FeNi-LDH layer can increase ZABs cycle life from 61.4 to 218.3 h. The in-situ electrodeposition FeNi-LDH on traditional air electrode strategy provides a simple method for enhancing the cycle life of ZABs.

Hybrid cobalt phthalocyanine polymer as a potential electrocatalyst for hydrogen evolution reaction

In this work, simple, novel, eco-friendly, low-cost and highly-active cobalt oxytyramine phthalocyanine polymer, poly[CoOTPc] is synthesized and characterized with various spectro-analytical techniques to demonstrate the successful construction of poly[CoOTPc]. In order to enhance the conductivity and electrocatalytic performance of poly[CoOTPc], an organic-hybrid composite with Ketjen-Black (KB) is prepared in different ratios and their activity was assessed towards hydrogen evolution reaction (HER). The linear sweep voltammogram of organic-hybrid composite (3.5:1.5 ratio of polymer to KB) exhibited least overpotential of −79 mV at −10 mA cm−2 current density towards HER in 0.5 M H2SO4 with a Tafel slope closer to the standard catalyst (Pt/C) both in lower and higher overpotentials. In addition, lower charge-transfer resistance is noticed at the hybrid catalyst and is comparable with the standard catalyst suggesting that the designed poly[CoOTPc]+KB organic-hybrid composite is one of the superior, low-cost electrocatalyst towards HER with excellent stability and efficiency for the large-scale integrated green energy systems.

Sulfur-rich polymer/Ketjen Black composites as lithium-sulfur battery cathode with high cycling stability

Lithium-sulfur (Li-S) battery is considered as one of the most promising energy storage devices due to its exceptional energy density. However, its development is largely hampered by the shuttle effect of lithium polysulfide and the sluggish electrochemical kinetics of sulfur cathode. In this study, a novel sulfur-rich polymer is synthesized through the inverse vulcanization of sulfur with 2,4,6,8-tetravinyl-2,4,6,8-tetramethylcyclotetrasiloxane (TVTCSi) and used as cathode material for Li-S batteries, which can effectively immobilize the lithium polysulfides through covalent bonds to impede its shuttling, leading to marked improvement in the cycling performance of the batteries. Furtherly, with the addition of Ketjen Black, the resulting composite cathode exhibited faster electrochemical reaction kinetics and higher cycling stability, which could deliver a reversible discharge capacity of 652 mAh g−1 after 500 cycles at a high current density of 0.5 C,0.5C with quite a low capacity decay rate of only 0.037% per cycle, which indicates broad perspectives of sulfur-rich polymer/Ketjen Black composite as cathode material in lithium-sulfur battery.

Pine needle-like FeCo@C grown in situ on nickel foam to enhance the oxygen evolution reaction

The design and synthesis of efficient, stable, and inexpensive oxygen evolution reaction (OER) catalysts is crucial for improving the energy efficiency of water electrolysis for hydrogen production. Herein, we propose a novel composite prepared by a one-step hydrothermal method as an OER catalyst: Fe3O4 and Co3O4 coated on carbon and grown on nickel foam (denoted as FeCo@C/NF). The added Ketjen black (KB) exhibits a unique branched-chain shape, resulting in a homogeneous pine needle-like structure of the catalyst with increased active sites. The overpotential of FeCo@C/NF is only 167 mV at a current density of 10 mA cm−2 in 1.0 M KOH electrolyte, a very low value compared with the conventional catalysts. The formation of the dense conductive network and heterojunctions inside the catalyst allows electrons to move freely across the carbon black and effectively reduces the carrier transfer resistance. Meanwhile, FeCo@C/NF also exhibits high electrochemical stability. These results show an effective thought for the design and synthesis of highly-efficient non-noble metal composite electrocatalysts.

Atomic V- and Co-Modified Ketjen Black–Sulfur Composite for High-Performance Lithium–Sulfur Batteries

Atomic V- and Co-Modified Ketjen Black–Sulfur Composite for High-Performance Lithium–Sulfur Batteries

A Porous Wrinkled Graphitic Carbon as Corrosion‐Resistant Carbon Support for Durable Fuel‐Cell Catalysts

AbstractThe lifespan of proton‐exchange membrane fuel cells heavily relies on the durability of the carbon support of cathode catalysts. However, commercial carbon supports like ketjenblack (KB) and Vulcan carbon (VC) face the challenge of balancing porosity, surface area, and electrochemical stability. To address this issue, a 3D porous wrinkled graphitic carbon (PWGC) is designed and synthesized using a catalyst‐free, plasma‐enhanced chemical vapor deposition approach. The resulting PWGC possesses a hierarchically porous structure with a high surface area, a high degree of graphitization, and exceptional corrosion resistance. As a result, the Pt/PWGC catalysts with the use of PWGC as the carbon support demonstrate superior high potential stability compared to those made with KB and VC as the carbon support. Additionally, a sacrificial layer strategy is introduced to further reduce PWGC corrosion, resulting in Pt@C/PWGC catalysts that show significantly improved durability in membrane electrode assembly tests. After 5K voltage cycles from 1.0 to 1.5 V, the retention of electrochemically active surface area approaches 56.8%, surpassing the 23.6% retention of commercial Pt/C catalysts tested under the same conditions.

Pearl-Structure-Enhanced NASICON Cathode toward Ultrastable Sodium-Ion Batteries.

Based on the favorable ionic conductivity and structural stability, sodium superionic conductor (NASICON) materials especially utilizing multivalent redox reaction of vanadium are one of the most promising cathodes in sodium-ion batteries (SIBs). To further boost their application in large-scale energy storage production, a rational strategy is to tailor vanadium with earth-abundant and cheap elements (such as Fe, Mn), reducing the cost and toxicity of vanadium-based NASICON materials. Here, the Na3.05 V1.03 Fe0.97 (PO4 )3 (NVFP) is synthesized with highly conductive Ketjen Black (KB) by ball-milling assisted sol-gel method. The pearl-like KB branch chains encircle the NVFP (p-NVFP), the segregated particles possess promoted overall conductivity, balanced charge, and modulated crystal structure during electrochemical progress. The p-NVFP obtains significantly enhanced ion diffusion ability and low volume change (2.99%). Meanwhile, it delivers a durable cycling performance (87.7% capacity retention over 5000 cycles at 5 C) in half cells. Surprisingly, the full cells of p-NVFP reveal a remarkable capability of 84.9 mAh g-1 at 20 C with good cycling performance (capacity decay rate is 0.016% per cycle at 2 C). The structure modulation of the p-NVFP provides a rational design on the superiority of others to be put into practice.

High-frequency supercapacitors with phosphorus-doped Ketjen black

Compact supercapacitors (SCs) have attracted attention for their great potential to replace bulky aluminum electrolytic capacitors (AECs) in alternating current (AC) line filtering applications. Herein, the fabrication of a high-frequency SC is reported using Ketjen black (KB) nanoparticles doped with phosphorus (P) to achieve a high areal capacitance of up to 2.26 mF cm−2 along with a high-rate capability, with a phase angle of –80.2° at 120 Hz. The high performance of the phosphorus-doped KB (designated PKB) SC with a 6 M KOH aqueous electrolyte is associated with its increased surface wettability and additional capacitive sites provided by the P-doping. Density functional theory (DFT) calculations further indicate that the P-doping enhances the interactions between the electrolyte ions and the carbon surface, thus leading to an improved electrochemical performance. These results suggest that the P-doped carbon-based SC could be highly favored in replacing conventional AECs in various high-frequency electronic devices.

A low-cost sulfur-loading material based on the modification of Ketjen Black for rechargeable lithium-sulfur battery

The practical application of lithium-sulfur (Li-S) battery is impeded by some technical hurdles such as short cycle life and poor capability, which is radically caused by the uncontrollable electrochemical reactions at the cathode. In this work, we develop a Ketjen Black carbon-based cathode material, modified with transition metals through the coordination fixing action of 2, 2′-bipyridine and followed with an annealing activation process, to be employed as the sulfur host in a Li-S battery. It is demonstrated that the decoration of Co and Fe on the matrix of carbon can substantially enhance the efficiency for catalytic conversion of polysulfides in Li-S batteries, thus greatly improving the performance, including capacity, rate capability and cycling life. This simple and economic strategy of modifying the commercial Ketjen Black shall accelerate the practical application of Li-S battery.

Influence of Sulfur Loading on Lithium‐Sulfur Battery Performance for Different Cathode Carbon Types

AbstractSince lithium‐sulfur (Li−S) batteries often employ an excess of carbon in the cathode to obtain high electrical conductivity and surface area, the kind and qualities of the carbon in the cathode significantly impact battery performance. Sulfur loading is an essential design element with a considerable influence on battery performance. To anticipate the relationship between the sulfur loading and the cycling performance, discharge capacity, and energy density/specific energy at the cell/pack level of the Li−S battery for different carbon types, an integrated research technique that couples experimental characterization and system‐level performance modeling is used. The capacity retention of Li−S cells with acetylene black is insensitive to S loading, while Li−S cells with carbon black present higher capacity retention at higher S loadings. Li−S cells with Ketjen Black cannot perform well at higher S loadings. At moderate S loadings, when discharge capacities are at maximum, Li−S cells achieve the highest system‐level metrics.

Increased utilization and mass activity of PtRu on reduced graphene oxide by heat treatment of its aerogel followed by composite with nanomaterials

The method to increase PtRu utilization and its catalytic activity of PtRu nanoparticles supported on reduced graphene oxide (RGO) by avoiding its restacking was proposed with the aim of developing an active catalyst for a direct methanol fuel cell. The heat treatment at 200 °C of the GO aerogel (GOA) prepared by freeze drying of GO ice was introduced to weaken the attractive force of the hydrogen bonding between the GO sheets followed by the composite with the nanoparticles, i.e., ketjenblack (KB), TiO2 and Ti4O7, at different weight ratios. The catalyst supported on the heat-treated GOA (RGOA), PtRu/RGOA, improved the PtRu utilization to some extent and also increased the ECSA and mass activity compared to that of PtRu/RGO. RGOA had fewer oxygen functional groups, especially the epoxy groups. Due to the treatment and composite, the PtRu utilization was increased from 66.5% for PtRu/RGO to 128.6 % for PtRu/RGOA + Ti4O7 (4:1) and the mass activity was improved from 50.7 A/g-PtRu for PtRu/RGO to 130.5 A/g-PtRu for PtRu/RGOA + Ti4O7 (1:1). The Ti4O7 nanoparticles showed the best catalytic performance for the composite suggesting that the strong interaction between Ti4O7 and the Pt nanoparticles was effective due to its high electronic conductivity.

High-Temperature Thermal Reactivity and Interface Evolution of the NMC-LATP-Carbon Composite Cathode.

Temperature-assisted densification methods are typically used in oxide-based solid-state batteries to suppress resistive interfaces. However, chemical reactivity among the different cathode components (which include a catholyte, the conducting additive, and the electroactive material) still represents a major challenge and processing parameters need thus to be carefully selected. In this study, we evaluate the impact of temperature and heating atmosphere in the LiNi0.6Mn0.2Co0.2O2 (NMC), Li1+xAlxTi2-xP3O12 (LATP), and Ketjenblack (KB) system. A rationale of the chemical reactions between components is proposed from the combination of bulk and surface techniques and overall involves a cation redistribution in the NMC cathode material that is accompanied by the loss of lithium and oxygen from the lattice enhanced by LATP and KB, which act as lithium and oxygen sinks. The final result is the formation of several degradation products, starting at the surface, that lead to a rapid capacity decay above 400 °C. Both the reaction mechanism and threshold temperature depend on the heating atmosphere, with the air atmosphere being more favorable compared to oxygen or any other inert gases.

Current collectors’ effects on the electrochemical performance of LiNi0.6Co0.2Mn0.2O2 suspension electrodes for lithium slurry battery

Take after the advantages of lithium-ion battery (LIB) and redox flow battery (RFB), semi-solid flow battery (SSFB) is a promising electrochemical energy storage device in renewable energy utilization. The flowable slurry electrode realizes decouple of energy and power density, while it also brings about new challenge to SSFBs, electron transport between active material and the out circuit. In this consideration, three types of current collectors (CCs) are applied to study the resistance and electrochemical performances of slurry cathodes within pouch cells for the first time. It proves that the electronic resistance (Re) between slurry electrode and the CC plays a decisive role in SSFB operation, and it is so large when Al foil is adopted that the cell cannot even work. Contact angle between Ketjen black (KB) slurry without active material (AM) and the CC is a preliminarily sign for the Re, the smaller the angle, the lower the resistance, and the better electrochemical performance of the cell.

High-capacity semi – Solid cathodes slurry evaluation in pouch cell

Fundamental studies of electrons transportation, and dispersion state of particles in slurry are crucial for constructing high performance semi – solid flow batteries (SSFBs). Therefore, this work provides an integrated electrode slurry preparation method, and the properties, such as conductivity, rheological behavior, anti – settling and electrochemistry of the slurries are comprehensively investigated. Single crystal LiNi0.6Co0.2Mn0.2O2 (SC622) is used as the active material due to its high energy storage ability and high structural stability, and ketjen black (KB) is selected as the conductive agent for its high electrical conductivity and high chemical inertness. Generally, the dispersion of SC622 within the electrolyte is difficult for its micron-sized particles and relatively high density. Therefore, KB nanoparticles are necessarily introduced for their extra function of providing rheological support to create thixotropic slurry, which is favorable for the flowable electrode preparation. Finally, a high discharge capacity of 167 mAh g−1 (based on SC622) at the current density of 8.0 mA g−1 is achieved by assembling pouch cells using the optimum slurry (30 wt% SC622 – 1.4 wt% KB). Noticeably, there are few works related to the electrochemical performance evaluation of the SSFBs slurries by this facile pouch cell, and in this study the final simulated result demonstrates the availability of this approach.

2H-MoS 2 Modified Nitrogen-Doped Hollow Mesoporous Carbon Spheres as the Efficient Catalytic Cathode Catalyst for Aprotic Lithium-Oxygen Batteries

2H-MoS ₂ Modified Nitrogen-Doped Hollow Mesoporous Carbon Spheres as the Efficient Catalytic Cathode Catalyst for Aprotic Lithium-Oxygen Batteries

Improved electrochemical performance of aqueous zinc-ion batteries with modified glass fiber separator by Ketjen Black

The development of aqueous zinc-ion batteries (AZIBs) with high capacity and high cycling stability has drawn increasing attention in recent years. Herein, a novel separator modification technology by spraying Ketjen black (KB) conductive carbon layer on the side of cathode is developed for improving the capacity and cycle stability of AZIBs. Benefiting from the KB separator, the Zn/MnO2 battery shows a high reversible specific capacity of 194.6 mAh g−1 at a current density of 2 A g−1 in a long-term cycle of 1500 cycles. In addition, the battery maintains 87% capacity retention after 6000 cycles at the current density 5 A g−1. The results indicate that the KB separator reduces the charge transfer impedance and improves the ion diffusion coefficient, showing excellent electrochemical kinetics. Meanwhile, the unique adsorption properties of KB separator reduce the attachment of by-products on the cathode surface. And the KB separator electrooxidizes Mn2+ ions on the surface to generate electrochemically active layered birnessite. Birnessite not only balances the capacity fading of the battery, but also improves the capacity of the battery, so that the battery has stable electrochemical performance. The method adapted in this work provides valuable insights for designing high performance aqueous zinc-ion secondary batteries.