Graphite Paper Research Articles

Laser‐Structured Graphite Paper Hybrid Anode with Selective Lithiophilic Grooves for Controlled Lithium Metal Deposition

Laser‐Structured Graphite Paper Hybrid Anode with Selective Lithiophilic Grooves for Controlled Lithium Metal Deposition

Polyaniline/graphene oxide nanocomposite as an innovative cathode for high energy density aqueous zinc-ion batteries

In order to resolve hard processability, poor conductive and lower capacity of polyaniline(PANI), We design and obtain a nanofiber network polyaniline/graphene oxide(PGO) and polyaniline/graphene oxide/manganese dioxide(PMGO) composite cathode. They are synthesized by electrochemical in-situ intercalative polymerization on oxidized graphite paper and assembled with the zinc anode into aqueous Zn-ion batteries(AZIBs). The initial discharged specific capacity of the PGO cathode is 224 mAh·g-1, and it is lower than that of the PMGO electrode when it discharges at 200mA·g-1. However, the capacity can reach 345 mAh·g-1 with better stability and reversibility compared to the PMGO under the same discharge/charge conditions. Characterization analysis and electrochemical studies show that the PGO composite cathode provides a large specific surface and charge/discharge channel, which optimizes the electrochemical performance of the battery. We also propose a new energy storage mechanism for intercalating PANI into graphene oxide(GO) layers to construct a nano-three-dimensional(3D) network for AZIBs and a proton pool with a hydrogen bond network of the PGO electrode. It is profitable for hindering the polarization, facilitating the electrode reaction, and enhancing the capacity and stability. For these reasons, the storage performance of the PGO electrode is superior to the polyaniline cathode reported at present.

Lightweight and thermally insulating carbon-bonded carbon fiber/graphite composite with enhanced in-plane heat-leading functionality for efficient thermal protection materials

Non-ablative thermal protection materials are subjected to localized high-density heat flux, facing extreme temperatures and uneven temperature distribution. Heat dredging is expected to enhance thermal protection efficiency and alleviate its resistance to temperature pressure. In this study, the function of in-plane (IP) heat leading is innovatively incorporated to increase the thermal-protection efficiency of carbon-bonded carbon fiber (CBCF) composites. The modified composite is prepared by a one-step integrated filter press process in which continuous flexible graphite paper (FGP) is used as the heat-leading layer. The typical micromorphology, mechanical response, thermal-insulation and heat-leading performance are determined. The CBCF/FGP composites with a 0.1 mm thick heat-leading layer exhibits a density of 0.22 g/cm3. The compressive strength increased by 160 % in the IP direction while remaining consistent in the through-the-thickness direction relative to that of the pure CBCFs. The thermal conductivity in the insulation and heat-leading directions at room temperature are 0.061 W/mK and 21.14 W/mK, respectively, indicating significant anisotropy with an approximately 350-fold difference. The incorporation of FGP effectively enhances the IP heat-leading capabilities of CBCF composites, potentially improving their thermal-insulation efficiency when combined with different matrix materials.

Pseudocapacitive Electrode Based on MnO2 Loaded Activated Charcoal on Graphite Paper for Sustainable Energy Storage

AbstractThe design of high‐performance electrode material without compromising energy and power density is critical for the advancement in hybrid electric vehicle technology. In this perspective, we have fabricated a MnO2 loaded activated charcoal‐based electrode on graphite paper as an endeavour to improve the energy storage capabilities. The electrode material is synthesized by employing a sustainable route and the structural, microstructural, and textural properties have been investigated. The electrochemical performance for energy storage is evaluated and the fabricated electrode on graphite paper exhibits remarkably high‐power density (811 W kg−1) maintaining high energy density (106 Wh kg−1) at the same time, along with high gravimetric specific capacitance value of 768 F g−1 at 2 mA cm−2. The obtained results demonstrate the excellent performance of the electrode material, suggesting MnO2 loaded activated charcoal as a prospective electrode material to meet the demand of hybrid electric vehicles as well as to contribute to our transitioning towards low‐to‐zero carbon emission technology.

Effects of current collectors on the self-discharge rates of supercapacitors with aqueous electrolyte

Current collectors play an important role in supercapacitors, impacting not only their electrochemical properties such as rate performance and cycling stability but also their self-discharge processes. In this study, we investigate the self-discharge behaviors of activated carbon supercapacitors with various current collectors, including titanium (Ti) foil, nickel (Ni) foil, 316 stainless steel (SS) foil, and graphite paper (GP), in an aqueous electrolyte. Our findings reveal that at a relatively low charging voltage of 0.8 V, supercapacitors with different current collectors exhibit similar decays in open circuit voltages (OCVs) after 12 h, indicating comparable self-discharge rates. However, at higher charging voltages, SS-based supercapacitors exhibit significantly faster self-discharge compared to Ti, Ni, and GP. Particularly at 1.6 V, the 12-h voltage retention rates decrease from over 60 % for Ti, Ni, and GP supercapacitors, to 46 % for SS supercapacitors. Analysis of the self-discharge mechanism suggests that increased side Faradaic reactions occurring at higher charging voltages in SS-based supercapacitors contribute to the accelerated self-discharge process compared to Ti, Ni, and GP supercapacitors.

3-Dimensional numerical study on carbon based electrodes for vanadium redox flow battery

Electrode materials are critical in determining the performance of Vanadium redox flow batteries (VRFB). This work aims at elucidating the difference between carbon-based electrodes for VRFB. The electrodes considered for the present study are Graphite felt, Carbon felt, Carbon paper, and Carbon cloth. To study the characteristic behavior of different electrode materials, a 3D unit cell numerical model was developed by coupling electrolyte flow and electrochemical reactions and mass transfer module apart from considering the electrode structural and material information such as porosity, permeability, thickness, conductivity, and specific area. The simulation results of this study suggest that the Graphite felt is the optimum choice as an electrode material for VRFB as it offers higher electrocatalytic activity, lower pressure drop, better performance, and lower cost. The study is also extended to a multilayer configuration of Carbon Paper and Carbon Cloth. The performance of multi-layered electrodes by stacking single sheets of Carbon Paper and Carbon Cloth electrodes are matched to meet the performance obtained with the Graphite felt electrode. It has been shown with the help of polarization curve and the pressure drop study that the performance of five layers of carbon cloth and nine layers of carbon paper match the performance of Graphite felt, approximately. The present study provides practical guidance for the design and optimization of VRFB electrodes.

Selective capacitive removal of Pb(II) ions from industrial wastewater using NF/Mn2CoO4@MoO2 electrodes

To achieve targeted removal of Pb2+ from industrial wastewater, a NF/Mn2CoO4@MoO2 composite electrode, synthesised using the hydrothermal method combined with electrodeposition technology, was employed to construct an asymmetric capacitive deionization (CDI) system to selectively electro-adsorb and desorb Pb2+ ions. The electrode exhibited pseudocapacitive characteristics in solutions containing Pb2+, facilitating rapid and reversible redox reactions. The asymmetric CDI system, utilising graphite paper as the positive electrode and NF/Mn2CoO4@MoO2 as the negative electrode, displayed exceptional adsorption performance at 1.4 V for 1 h, decreasing the Pb2+ concentration from 50 ppm to 4 ppb, achieving an adsorption capacity of 156.24 mg g−1, and displaying outstanding cyclic stability. Moreover, the electrode demonstrated preferential adsorption of Pb2+ in mixed solutions containing multiple heavy metal ions, with relative removal coefficients of 4.48 − 19.86 compared with other ions. Analysis of the adsorption mechanism indicated that during the adsorption process, Pb2+ was embedded between MoO2 layers, disrupting the electron cloud symmetry and triggering an oxidation reaction. Octahedral MoO2 then lost electrons and transformed into tetrahedral [MoO4]2-, forming PbMoO4 with embedded Pb2+ between the layers, and achieving effective removal of Pb2+ with high selectivity. Molecular dynamics simulations and density functional theory (DFT) calculations confirmed the high selectivity of the prepared electrode for Pb2+ ions based on stronger binding of Pb2+ to MoO2 than other ions. The electrode has application potential for the capacitive removal of Pb2+ from industrial effluent through CDI technology.

Laser-assisted preparation of vertically aligned reduced graphene oxide/tannic acid arrays for flexible aqueous zinc-ion hybrid capacitors

Aqueous zinc-ion hybrid capacitors (AZHCs) are considered an encouraging energy storage candidate owing to their promising environmental benignity and electrochemical performance. To give full play to the advantages of AZHCs, vertically aligned reduced graphene oxide/tannic acid (V-rGO/TA) arrays are constructed on the laser-pretreated graphite paper (LGP) as flexible carbon-based cathodes (V-rGO/TA/LGP) for AZHCs by a facile laser reduction method. The vertical structure of rGO exhibits abundant physical adsorption sites and ion/electron transfer channels, and the residual oxygen-containing groups of rGO provide favored chemical adsorption sites, which can enhance Zn2+ ion storage. In addition, the TA molecules contribute extra capacity by reversible redox reaction (phenol-quinone transition), further improving the electrochemical performance of the electrode. Consequently, the assembled quasi-solid-state AZHC based on the optimized V-rGO/TA/LGP cathode possesses a high specific capacity of 136.6 µAh cm−2 and a maximum energy density of 109.3 μWh cm−2. In addition, the device exhibits good flexibility with a capacity retention of 97.0 % even after 3000 bending cycles. This design strategy opens up a new approach to construct a vertically aligned carbon material for achieving high-performance flexible AZHCs and realizing their practical applications.

Self-powered sodium borohydride alkaline fuel cell for efficient removal of lead(II) and copper(II)

Heavy metals in industrial wastewater cause serious environmental pollution and they are easy to accumulate and difficult to degrade. Copper and lead are two typical heavy metals, and it is of great significance to remove them at the same time. This work shows a strategy of reducing and removing Pb(II) and Cu(II) by self-powered non-biological fuel cell (SP-nBFC) with dual-chamber reactor. Therein, sodium borohydride in alkaline solution as fuel (electron donor) was electrooxidized on nicke1 foam (NF) at anode and Pb(II) and Cu(II) ions (electron acceptors) in strong acidic solution were electro-reduced at Bi/MXene/GP cathode (bismuth nanoparticles and MXene modified graphite paper (GP)).Additionally, a proton exchange membrane, Nafion, was introduced into form complete circuit by offering ions channel. The results showed that Cu(II) and Pb(II) were reduced to Cu and Pb, and the SP-nBFC could produce electricity in this process without external energy consumption. The Bi/MXene/GP cathode could increase significantly removal efficiencies of Cu(II) and Pb(II), which were higher than about 37.0 %, 22.5 % for Cu(II) and 25.7 %, 16.3 % for Pb(II) than those of GP and MXene/GP cathode. This system could obtain a high Cu(II) removal efficiency (RE, 99.3 %) and moderate Pb(II) RE of 56.8 %, and acquire Cu and Pb sediments in cathode chamber. Furthermore, the proposed system could generate 923 mV of maximum potential and 1420 mW/m2 of maximum power density in 48 h. Thus, this SP-nBFC system provides a viable method for treatment of Cu(II) and Pb(II) pollution and generating electricity simultaneously, and also has prospective approach for other heavy metals remediation.

Catalytic role of biogenic gold nanoparticles in improving Cr(VI) removal efficiency of biocathode microbial fuel cells

AbstractBACKGROUNDBiogenic metal nanoparticle‐modified electrodes have a promising prospect for improving the efficiency of microbial fuel cells (MFCs) for hexavalent chromium (Cr(VI))‐containing wastewater treatment. In this study, a graphene (GO) electrode was modified with chemical gold nanoparticles (ChemAu) and biogenic gold nanoparticles (BioAu), respectively, and the two modified electrodes were then used as MFC biocathode electrodes to treat Cr(VI)‐containing wastewater.RESULTSThe results demonstrated that the BioAu/GO biocathode‐based MFC obtained the highest power density (95.78 ± 1.11 mW m−2) and Cr(VI) removal rate (2.17 ± 0.51 mg L−1 h), which were 13.19 and 1.03 times higher than those of the graphite paper biocathode‐based MFC, respectively. The Cr(VI) removal efficiency of the BioAu/GO biocathode‐based MFC under close‐circuit condition reached 87.61 ± 0.19%, which was 3.74 times higher than that recorded under open‐circuit conditions, indicating the critical role of the bioelectrochemical reduction reaction mediated by the BioAu/GO biocathode on Cr(VI) removal.CONCLUSIONThe BioAu/GO electrode first confirmed its superior performance to the ChemAu/GO electrode in Cr(VI)‐reducing MFCs due to its excellent material properties. This study provides a technical reference for the exploration of efficient bioelectrode materials based on biogenic metal nanoparticles for MFCs to treat recalcitrant pollutant‐containing wastewater. © 2024 Society of Chemical Industry (SCI).

Tailoring Interfaces of All-Carbon Electromagnetic Interference Shielding Materials for Boosting Comprehensive Performance.

Electromagnetic interference (EMI) shielding materials with lightweight, high shielding effectiveness, excellent chemical stability, especially minimized secondary electromagnetic pollution, are urgently desired for integrated electronic systems operating in harsh working environments. Here in this study, by systematically engineering and matching the interfacial properties of carbon-based membrane materials, i.e., graphite paper, whisker carbon nanotube paper (WCNT paper), carbon nanotube film (CNT film), bucky paper (BP), and carbon cloth (CC) with three-dimensional (3D) porous carbon nanotube sponge (CNTS), we successfully constructed a series of multifunctional all-carbon EMI shielding materials, which exhibit excellent average shielding effectiveness of over 90 dB with a thickness of about 1 mm and dramatically minimized secondary electromagnetic reflection. Moreover, benefiting from the all-carbon nature and engineered interfaces, our CMC materials also exhibit excellent photothermal and Joule heating performances. These results not only provide guidance for designing advanced multifunctional all-carbon EMI shielding materials but also shed light on the hidden mechanism between interfaces and performances of composite materials.

Metal- and binder-free dual-ion battery based on green synthetic nano-embroidered spherical organic anode and pure ionic liquid electrolyte

Dual-ion batteries (DIBs) have attracted extensive attention and investigations due to their inherent wide operating voltage and environmental friendliness. Nevertheless, the vast majority of DIBs employ metal-based anode active materials or electrolytes, which are relatively costly and unsustainable. Moreover, the utilization of binders and current collectors in the preparation of cathodes and anodes reduces the energy density to a certain extent, which weakens the advantages of DIBs. Here, we synthesized three types of binder-free nano-embroidered spherical polyimide anode materials composed entirely of renewable elements, paired with pure ionic liquid electrolyte without metal elements and flexible self-supporting independent graphite paper cathode without current collector, to construct a class of totally metal and binder-free DIBs. It significantly improves specific discharge capacity, energy density, cyclic stability, and fast charging performance while remarkably reducing costs and self-discharge rate. Additionally, we overcame the drawbacks of conventional synthesis methods and innovatively prepared nanoscale polyimide materials by a green and facile hydrothermal method, which effectively minimizes synthesis costs and avoids risks. This novel battery system design strategy will promote the advancement of low-cost, high-performance DIBs and could be a promising candidate for large-scale energy storage applications.

Ratiometric electrochemical determination of hydroxyl radical based on graphite paper modified with metal-organic frameworks and impregnated with salicylic acid.

Hydroxyl radical (•OH) detection is pivotal in medicine, biochemistry and environmental chemistry. Yet, electrochemical method-specific detection is challenging because of hydroxyl radicals'high reactivity and short half-life. In this study, we aimed to modify the electrode surface with a specific recognition probe for •OH. To achieve this, we conducted a one-step hydrothermal process to fabricate a CoZnMOF bimetallic organic framework directly onto conductive graphite paper (Gp). Subsequently, we introduced salicylic acid (SA) and methylene blue (MB), which easily penetrated the pores of CoZnMOF. By selectively capturing •OH by SA and leveragingtheelectrochemical signal generated by the reaction product, we successfully developed an electrochemical sensor Gp/CoZnMOF/SA + MB. The prepared sensor exhibited a good linear relationship with •OH concentrations ranging from 1.25 to 1200 nM, with a detection limit of 0.2 nM. Additionally, the sensor demonstrated excellent reproducibility and accuracy due to the incorporation of an internal reference. It exhibited remarkable selectivity for •OH detection, unaffected by otherelectrochemically active substances. The establishment of this sensor provides a way to construct MOF-modified sensors for the selective detection of other reactive oxygen species (ROS), offering a valuable experimental basis for ROS-related disease research and environmental safety investigations.

Enhanced solar-thermal and electro-thermal storage performance of solid-solid composite phase change material

Phase change material (PCM) is a highly sought-after thermal storage medium, but cannot directly reserve solar energy and electricity. In this study, a pentaglycerine (PG)-based composite solid-solid phase change material (SSPCM) was developed with the ability to convert and store solar-thermal and electro-thermal energy. The composite was prepared using a high temperature melting process with graphite paper (GP) and carbon nano tube (CNT) as functional additives. The performance tests showed that the composite has a phase change temperature of 80.5 °C, latent heat of 145.6 J/g, supercooling degree of 7.9 °C and electrical conductivity of 15.3 S/m. This composite could undergo solid-solid phase change and store solar energy in the form of latent heat under simulated sunlight. The phase change process can also be driven by direct current, with a 10 V power supply increasing the temperature of the composite to 90 °C within 32 min. These properties make the developed SSPCM promising for energy storage applications.

High areal-capacitance based extremely stable flexible supercapacitors using binder-free exfoliated graphite paper electrode

The highly porous and binder-free flexible paper electrodes can enhance the specific capacitance of symmetric supercapacitors (SCs) due to their large surface and effective ion diffusion pathways. We synthesized the exfoliated graphite (ExG) by the thermal exfoliation method of chemically treated graphite flakes and compressed it into a paper-like thin sheet (binder-free) of ∼0.15 mm thickness. The coin cell SCs with copper (Cu) and stainless steel (SS) as current collectors have been fabricated for the electrochemical measurement. The cyclic voltammetry and galvanostatic charge/discharge measurements are investigated at various scan rates and current densities. The SCs with Cu foil as a current collector perform better than SS-based SCs. The Cu current collector-based SCs showed a specific capacitance of 37.08 mF cm−2, whereas it was ∼29.98 mF cm−2 for SS-based SCs at a 0.01 V s−1 scan rate across a 0–0.6 V potential window. Approximately no degradation in charge storage capacity for more than 15 000 cycles at 0.1 V s−1 shows the ultra-stability of the flexible ExG-based binder-free electrodes. A digital watch is powered using the fabricated pouch cell supercapacitor with copper-based current collectors to show the potential of SCs.

Exploring in electrochemical behaviors and anions storage characteristics of carbonaceous materials in molten salts Ni/NiCl2-graphite battery

Carbonaceous materials that possess reversible anions storage capacity and can worked as the cathode for Ni/NiCl2-Graphite battery. However, differences in storage capacity of carbonaceous cathodes and factors affecting anions storage capacity have not been thoroughly investigated. Here, we systematically evaluated the electrochemical properties and intercalation reaction mechanism of carbonaceous materials cathodes firstly. Expanded graphite and graphite paper cathodes display the highest specific capacity of 72 mAh/g and diffusion-controlled capacity ratios (∼98 %). X-ray powder diffraction and Raman spectroscopy analysis on the graphite intermetallic compounds confirmed the presence of stage-5 intercalation/de-intercalation reactions. Density functional theory calculation and ionic diffusion model analysis showed that the intercalation and diffusion process of AlCl4- in graphite interlayers play a crucial role in anions storage reaction. Rich-in-edged outer graphite-layers are more conducive to form intercalation reaction active sites and store anions effectively. The expanded graphite electrode exhibits the highest intercalation reaction ratio (φR-GP = 1.40), confirming sufficient intercalation reaction active sites in each unit mass. And the multiple wrinkles and curled graphite sheets in expanded graphite provide adequate ionic transport/diffusion channels during electrochemical intercalation/de-intercalation reactions. Our findings provide significant support for understanding anions storage behaviors and designing cathodes with high anions storage capacity in the Ni/NiCl2-Graphite battery.

Experimental research on thermoelectric characteristics of a thermoelectric generator with external influencing factors optimization

The external influencing factors, the thermal interface material, load-bearing brick weight, and temperature difference, of a thermoelectric generator (TEG) device were experimentally examined. The micro heat pipe array (MHPA), as one novel thermal interface material, was investigated. The multi-variable coupling approach is used to analyze the intrinsic coupling correlation of the external influencing factors. The dimensionless synthesis economic factor index was proposed to analyze the improvement of thermoelectric characteristics, which can quickly assess the contact thermal resistance of different thermal interface materials. The results showed that the load power and load voltage generally increase with increased temperature differences. The contact thermal resistance decreases with increased load-bearing brick weight, but the decrement gradually decreases. The thermal interface material plays an important role in thermoelectric characteristics. The load-bearing brick weight performs little impact on the non-thermal interface material (NTIM) scheme. The two thermal conductive silicone grease schemes noticeably reveal better thermoelectric characteristics than those of the graphite paper schemes, although the thermal conductivity of thermal conductive silicone grease are much lower than that of graphite paper. The MHPA scheme exhibit the best thermoelectric characteristics, and its dimensionless synthesis economic factor index can be up to 371.81 %.

A novel chlorine-zinc dual-ion battery

The development of new rechargeable safe batteries featuring high discharge platforms, low cost and environmental protection is one of the most ideal goals to achieve energy storage. Here we develop a novel chlorine-zinc dual-ion battery (C-ZDIB) that uses graphite paper as cathode, zinc as cathode, and (CH3)4NCl + Na2CO3 salt in water as electrolyte. The battery operates by redox reaction between Zn with Zn(OH)42− on the anode side and between ClO− and Cl− on the cathode side. The battery exhibits high discharge platform (about 2.6 V), high discharge capacity (226.2 mAh/g at 0.5 A/g), and long cycle life.

An Ultrahigh-Capacity Dual-Ion Battery Based on a Free-Standing Graphite Paper Cathode and Flower-Like Heterojunction Anode of Tin Disulfide and Molybdenum Disulfide.

Dual-ion batteries have been considered as a competitive energy-storage device. However, owing to the lack of suitable high-capacity density and rapid-charging electrode materials, designing a cost-effective and high-performance dual-ion battery is still a great challenge. Herein, an ultrahigh-capacity dual-ion battery is constructed based on a carbon-nanotubes (CNTs) containing SnS2 -MoS2 @CNTs heterojunction anode and highly crystalline free-standing graphite paper serves as cathode. The SnS2 -MoS2 @CNTs heterojunction consisting of ultrathin nanosheets was prepared via a facile two-step hydrothermal method and shows flower-like morphology and high crystallinity. Benefiting from the unique design concept, the graphite paper/SnS2 -MoS2 @CNTs dual-ion battery delivers a high capacity of 274.2 mAh g-1 at 100 mA g-1 and has an outstanding capacity retention of 95 % after 300 cycles under 400 mA g-1 . Even at a high current density of 2 A g-1 the battery still retains a considerable capacity of 112.3 mAh g-1 . More importantly, the battery shows an extremely low self-discharge of 0.006 % h-1 after resting for 24 h. Characterization using SEM and XRD further demonstrate the excellent cycling stability and good reversibility. Consequently, this constructed dual-ion battery could be a promising energy storage device and provide new insights for the design of high-performance dual-ion batteries.

Self-supporting Co-MoOx@N-doped carbon/expanded graphite paper for efficient water splitting catalyst

Molybdenum oxides are widely used as electrocatalysts due to their polymetallic oxidation state, abundant reactive sites and low production cost. However, the low electrical conductivity and easy agglomeration has limited their practical application. Here, MoO3 nanowires encapsulated with ZIF-67 polyhedra were grown in situ on expanded graphite paper (EGP) by a simple hydrothermal synthesis method, and then the precursors were pyrolyzed to obtain self-supported Co-MoOx@N-doped carbon/EGP composites. Thanks to the three-dimensional porous structure and the synergistic effect of Co and multi-valance MoOx, the as-prepared Co-MoOx@N-doped carbon/EGP exhibits the excellent performances of OER (η10 = 256 mV) and HER (η10 = 138 mV), and a small Tafel slope and good durability. Furthermore, the assembled water splitting device achieved a current density of 10 mA cm−2 at a low voltage of 1.62 V and the excellent stability after 24 h continuous water splitting.