Non-metallic Electrodes Research Articles

The Role of Interfacial Effects in the Impedance of Nanostructured Solid Polymer Electrolytes

The role of interfacial effects on an ion-conducting poly(styrene-b-ethylene oxide) (PS-b-PEO or SEO) diblock copolymer doped with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) was investigated by electrochemical impedance spectroscopy (EIS). Coating the surface of commonly used stainless steel electrodes with a specific random copolymer brush increases the measured ionic conductivity by more than an order of magnitude compared to the uncoated electrodes. The increase in ionic conductivity is related to the interfacial structure of the block copolymer domain morphology on the electrode surface. We show that the impedance associated with the electrode–electrolyte interface can be detected using nonmetallic electrodes, allowing us to distinguish the ionic conductivity behaviors of the bulk electrolyte and the interfacial layers for both as-prepared and annealed samples.

SWEL-V: A low-cost salt-water electrolyzer. Comparative analyses with the proton exchange membrane, PEM, electrolyzer

Seawater is the largest resource on earth which makes the hydrogen production directly from seawater an economically attractive solution if the corrosion problems are solved. Traditionally in the electrolysis analysis, both electrodes are made of metals. The produced oxygen and chlorine in the electrolysis process cause high rates of corrosion resulting in using expensive alloys to slow down the corrosion process. A novel solution to the corrosion problem is introduced, tested, and experimentally proved. The novelty of the solution relies on replacing the classic high-cost positive electrodes with a non-metallic, low cost, one [1,2]. The non-metallic electrode is made of surface rock portions with high pore volume and high pores connectivity and saturated with saline water. The experimental results are compared to the freshwater Proton Exchange Membrane PEM electrolyzers. The comparison proved that the novel solution solved the corrosion challenges of the metallic electrodes with excellent efficiency and hydrogen purity.

Enhancing Conductivity in Silicon Heterojunction Solar Cells with Silver Nanowire-Assisted Ti3C2Tx MXene Electrodes for Cost-Effective and Scalable Photovoltaics.

Silicon heterojunction (SHJ) solar cells have set world-record efficiencies among single-junction silicon solar cells, accelerating their commercial deployment. Despite these clear efficiency advantages, the high costs associated with low-temperature silver pastes (LTSP) for metallization have driven the search for more economical alternatives in mass production. 2D transition metal carbides (MXenes) have attracted significant attention due to their tunable optoelectronic properties and metal-like conductivity, the highest among all solution-processed 2D materials. MXenes have emerged as a cost-effective alternative for rear-side electrodes in SHJ solar cells. However, the use of MXene electrodes has so far been limited to lab-scale SHJ solar cells. The efficiency of these devices has been constrained by a fill factor (FF) of under 73%, primarily due to suboptimal charge transport at the contact layer/MXene interface. Herein, a silver nanowire (AgNW)-assisted Ti3C2Tx MXene electrode contact is introduced and explores the potential of this hybrid electrode in industry-scale solar cells. By incorporating this hybrid electrode into SHJ solar cells, 9.0 cm2 cells are achieved with an efficiency of 24.04% (FF of 81.64%) and 252 cm2 cells with an efficiency of 22.17% (FFof 76.86%), among the top-performing SHJ devices with non-metallic electrodes to date. Additionally, the stability and cost-effectiveness of these solar cells are discussed.

Quantum Confinement and End-Sealing Effects for Highly Sensitive and Stable Nitrogen Dioxide Detection: Homogeneous Integration of Ti3C2Tx-Based Flexible Gas Sensors.

The real-time and room-temperature detection of nitrogen dioxide (NO2) holds significant importance for environmental monitoring. However, the performance of NO2 sensors has been hampered by the trade-off between the high sensitivity and stability of conventional sensitive materials. Here, we present a novel fully flexible paper-based gas sensing structure by combining a homogeneous screen-printed titanium carbide (Ti3C2Tx) MXene-based nonmetallic electrode with a MoS2 quantum dots/Ti3C2Tx (MoS2 QDs/Ti3C2Tx) gas-sensing film. These precisely designed gas sensors demonstrate an improved response value (16.3% at 5 ppm) and a low theoretical detection limit of 12.1 ppb toward NO2, which exhibit a remarkable 3.5-fold increase in sensitivity compared to conventional Au interdigital electrodes. The outstanding performance can be attributed to the integration of the quantum confinement effect of MoS2 QDs and the conductivity of Ti3C2Tx, establishing the main active adsorption sites and enhanced charge transport pathways. Furthermore, an end-sealing effect strategy was applied to decorate the defect sites with naturally oxygen-rich tannic acid and conductive polymer, and the formed hydrogen bonding network at the interface effectively mitigated the oxidative degradation of the Ti3C2Tx-based gas sensors. The exceptional stability has been achieved with only a 1.8% decrease in response over 4 weeks. This work highlights the innovative design of high-performance gas sensing materials and homogeneous gas sensor techniques.

In-situ observation of hydrogen nanobubbles formation on graphene surface by AFM-SECM

Gas bubble evolution is an important phenomenon in many electrochemical processes and it is highly sensitive to the surface properties. Here we visualize the gas bubble dynamics on the surface of different graphene substrates during hydrogen evolution reaction (HER) using atomic force microscopy combined with scanning electrochemical microscopy. The low overpotential and low surface hydrophobicity of few-layer graphene formed on C-phase SiC causes the uniform distribution of hydrogen nanobubbles, which easily depart from the surface during the reaction. Conversely, the high overpotential and more hydrophobic surface of HOPG induces hydrogen bubbles to linger on the surface for an extended duration, leading to its accumulation and the subsequent formation of microbubbles. This in-situ nanoscale electrochemical mapping of hydrogen bubble dynamics provides new insight into electrocatalytic HER that occurs on non-metal electrodes.

Spin coated ultrathin PEDOT:PSS/SWCNT film with high electronic conductivity

Conductive Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been extensively used as non-metallic electrodes. However, the relatively low electrical conductivity of pristine PEDOT:PSS film restricts its further application. Although doping high content conductive filler or increasing the film thickness are effective for enhancing the electrical property, the transparency is sacrificed, which limits the application of PEDOT:PSS films. In this study, preparing PEDOT:PSS composite film with highly conductive and transparent property was the primary purpose. To achieve this goal, single-walled carbon nanotubes (SWCNTs) and dimethyl sulfoxide (DMSO) was chosen to composite with PEDOT:PSS. The spin-coated SWCNT/PEDOT:PSS composite film exhibited excellent electrical conductivity and transparency. The electrical conductivity of composite film with desired transmittance property (78%) reached the highest value (1060.96 S cm−1) at the SWCNTs content was 6 wt%. Under the modification process applied in this work, the non-conductive PSS was partially removed by incorporated DMSO and SWCNTs. Then, the molecular chains of PEDOT stretched and adsorbed onto the surface of SWCNTs, forming a highly efficient three-dimensional conductive structure, which contributed to the enhancement of electrical conductivity and transparency. Additionally, the spin-coating process allowed for the reduction of film thickness, ensuring better transparency. This research contributed to expanding the further applications of PEDOT:PSS films in high-performance transparent film electrodes.

Excellent sodium metal deposition enabled by three-dimensional porous structures with natrophilic Ni-Sn alloy

Na metal has long been an ideal potential anode material for sodium secondary batteries due to its own superiority; however, the Na dendrite problem during cycling makes it face a great obstacle in application. Here, we grow sodiophilic thin film materials with tin and nickel-tin components uniformly on three-dimensional nickel foam (3D-Ni) to obtain a 3D sodiophilic composite framework (namely 3D-NiSn) using a reproducible and mass-produced electrodeposition strategy. The combination of sodiophilic film (NiSn) and 3D porous framework could lower nucleation overpotential of Na and accelerate ions diffusion, hence inducing the uniform deposition and reversible stripping of sodium and inhibiting the growth of Na dendrites, which makes the 3D-NiSn/Na composite anode exhibit good performance compared to 3D-Ni/Na and Na-foil. The symmetrical cells with 3D-NiSn/Na can maintain up to 2500 h at 2 mA cm−2 and 1 mAh cm−2 with a low overpotential of around 30 mV during the whole cycling process. Additionally, the 3D-NiSn/NaǁNa3V2(PO4)3 full cells deliver good cycle stability with a high specific capacity of around 98.1 mAh g−1 at 3C for over 600 cycles. This work provides an idea for constructing low-cost and commercially available Na metal electrodes toward high-performance SIBs.

The enhancement of intelligent electric response properties in the Polymer Gel Artificial Muscle (PGAM) by incorporating micro/nanoscaled doping and regulation of Graphene Oxide (GO)

To align with the principles of environmental conservation and sustainable progress, a Polymer Gel Artificial Muscle (PGAM) was designed with a sandwich-like configuration, comprising two non-metallic electrode membranes enclosing an electrically-actuated membrane. This PGAM exhibited promising prospects due to its advantageous features such as lightweight, intelligibility, flexibility, and excellent activity. However, despite the widespread utilization of polymer gels, their investigation into intelligent electric response property remained a significant challenge. This study investigated the intelligent electric response properties of the enhanced PGAM by incorporating micro/nanoscaled doping with varying amounts of Graphene Oxide (GO). A control group consisting of a PGAM without GO was also utilized, allowing for the analysis of the regulatory mechanism behind GO-doped PGAM. The findings indicated that a doping amount of 0.03 wt% of GO resulted in a maximum peak difference of 16.08 mN/g in the output force density of PGAM during multiple cycles, with a maximum change rate of 21.13%. The PGAM demonstrated a maximum output force density of 15.06 mN/g during a single cycle when doped with 0.03 wt% of GO. Furthermore, electrochemical analysis of the PGAM revealed that at the same doping amount of 0.03 wt%, the specific capacitance reached its peak value of 324 nF·cm−2, while the resistance reached its minimum value of 1.61 Ω. In summary, the incorporation of GO doping has been found to enhance the intelligent electric response properties of PGAM, thereby offering a novel approach for the advancement of flexible actuators exhibiting superior intelligent electric response property.

Green Hydrogen Production Directly from Seawater with No Corrosion Using a Nonmetallic Electrode: A Novel Solution and a Proof of Concept

Why Hydrogen. Nowadays, the energy industry and research laboratories are heavily working on developing ideas and methods to reduce and/or eliminate the carbon dioxide emission to control the problem of global warming. The solution relies on finding alternative green energy resources to reduce the world’s dependence on conventional fossil hydrocarbon energy. Green hydrogen gas from water stands on the top of the alternative resources since it does not produce carbon dioxide when burned and in return does not add to global warming. Since seawater is the largest resource on earth, this makes the hydrogen production from seawater the most economically attractive solution. It is very important to avoid using fresh water as a source of hydrogen energy due to the dependence of all living creatures, humans, animals, plants, etc., on such very limited resources. In this paper, the applications of the proposed novel solution of green hydrogen production directly from seawater relies on solving one of the major problems, electrode corrosion. Generating Hydrogen. The direct method to produce green hydrogen from seawater is the electrolysis technique. This technique requires a direct current power supply for the positive and the negative electrodes. The outcome of the electrolysis is decomposing the saltwater to its positively charged hydrogen and sodium ions at the negative electrode and its negatively charged oxygen and chlorine ions at the positive electrode. The Real Challenge. Traditionally in the electrolysis analysis of water, both electrodes are made of metals. At the positive electrode, both the oxygen and the chlorine cause a high rate of corrosion to that electrode. This results in the interruption of the electrolysis process, bad water condition due to the corrosion deposits, and cost burden due to the need to periodically replace the corroded electrodes and/or use high-cost corrosion-resistant alloys. The Novel Solution. A low-cost but powerful solution to the corrosion problem is introduced, tested, and experimentally proved. The novelty of the solution relies on replacing the classic special high-cost metallic positive electrode with a nonmetallic, no-cost, one. The nonmetallic electrode is made of surface rock portions that have high porosity and pore volume and high permeability and pore connectivity and is saturated with saline water. Surface rocks with the above properties exhibit very low resistivity and hence conduct electricity like metallic electrodes. The voltage and the current conducted by such electrode are controlled by the electrode geometry, connectivity, and physical properties. Results and Discussions. Multiple experiments using the proposed nonmetallic high-porosity and high-permeability positive electrode are conducted and presented in this paper. The experimental work is based on testing multiple rock electrodes with different rock properties, sizes, and connectivity in comparison to the metallic ones. The comparison showed that the novel solution solved the corrosion challenges of the metallic electrodes with excellent efficiency.

Aqueous Casting of Polymeric Electrolyte Membranes for Solid Rechargeable Na Batteries

Organic solid electrolytes for rechargeable batteries are usually produced by dissolving or suspending all components and casting. For decades, acetonitrile has been widely used despite its rapid reaction with alkali metals, forming toxic products such as cyanide. Using large amounts of acetonitrile for industrial applications may pose health and environmental concerns. In addition, researchers claim that even if the solid electrolyte membranes contain residual trace water, this may positively affect the transport properties of Na ions in PEO, and those batteries with electrolytes containing trace water showed significantly improved electrochemical performance. Here, an aqueous medium was considered for casting solid polymer electrolyte membranes. Na ions conducting membranes produced with water were characterized and compared to traditional ones, produced with organic solvents. Spectral studies and electrochemical measurements of symmetric cells with Na metal electrodes under static and dynamic conditions and all-solid-state Na batteries showed that the membranes cast from aqueous media are similar to their counterparts, cast from organic volatile solvents. Surprisingly, the water-cast membranes exhibit better performance as solid electrolytes than similar membranes prepared with organic solvents.

Gaining insight into molecular tunnel junctions with a pocket calculator without I-V data fitting. Five-thirds protocol.

The protocol put forward in the present paper is an attempt to meet the experimentalists' legitimate desire of reliably and easily extracting microscopic parameters from current-voltage measurements on molecular junctions. It applies to junctions wherein charge transport dominated by a single level (molecular orbital, MO) occurs via off-resonant tunneling. The recipe is simple. The measured current-voltage curve I = I(V) should be recast as a curve of V5/3/I versus V. This curve exhibits two maxima: one at positive bias (V = Vp+), another at negative bias (V = Vp-). The values Vp+ > 0 and Vp- < 0 at the two peaks of the curve for V5/3/I at positive and negative bias and the corresponding values Ip+ = I(Vp+) > 0 and Ip- = I(Vp-) < 0 of the current is all information needed as input. The arithmetic average of Vp+ and |Vp-| in volt provides the value in electronvolt of the MO energy offset ε0 = EMO - EF relative to the electrode Fermi level (|ε0| = e(Vp+ + |Vp-|)/2). The value of the (Stark) strength of the bias-driven MO shift is obtained as γ = (4/5)(Vp+ - |Vp-|)/(Vp+ + |Vp-|) sign (ε0). Even the low-bias conductance estimate, G = (3/8)(Ip+/Vp+ + Ip-/Vp-), can be a preferable alternative to that deduced from fitting the I-V slope in situations of noisy curves at low bias. To demonstrate the reliability and the generality of this "five-thirds" protocol, I illustrate its wide applicability for molecular tunnel junctions fabricated using metallic and nonmetallic electrodes, molecular species possessing localized σ and delocalized π electrons, and various techniques (mechanically controlled break junctions, STM break junctions, conducting probe AFM junctions, and large area junctions).

Electrochemical investigations of PVdF-HFP-NaTFSI-[BMPYr][TFSI] polymer-salt-IL electrolyte for Na-rechargeable battery

Sodium-ion batteries (SIBs) are being aggressively pursued for potential use in energy storage systems due to the natural abundance and low cost of sodium. In the present investigation, structural, thermal and electrochemical properties of a ionic liquid based Na-ion conducting polymer-salt-IL electrolytes (IL-NCPEs) formed using copolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) salt along with IL; 1-butyl-1-methypyrrolidinium bis(trifluoromethanesulfonyl)imide ([BMPYr] [TFSI]) is being reported. The samples were characterized using ionic conductivity, transference number measurement, thermal & electrochemical studies as a function of wt% IL. Incorporated [BMPYr][TFSI]-IL in the NCPE (i.e., PVdF-HFP + 10 wt% NaTFSI) modifies the different physicochemical properties such as complex formation, thermal, transport and electrochemical properties. The ionic conductivity of prepared IL-NCPEs has been found to increase with increasing the content of [BMPYr][TFSI]-IL and reaches to a maximum value of ∼0.85 mS/cm (at 30 °C). Also, the temperature dependent ionic conductivity obeys Arrhenius type thermally activated behaviour. For the optimized [BMPYr][TFSI]-IL, compatibility of IL-NCPEs with Na-metal electrode, high total ionic transference number (tionic ∼ 0.98), cationic transference number (tNa+ ∼ 0.31) and wide electrochemical stability (ESW ∼ 4.0 V) have been obtained. The above obtained properties of the prepared IL-NCPEs are promising for application in Na-rechargeable battery.

High Areal Capacity Cycling of Three-Electrode Sodium/NBA/Sodium Cells

The cycling stability of Li and Na metal electrodes is influenced by the interface with the solid electrolyte. Study of the cycling behavior at areal capacities >>0.5 mAh/cm2 are uncommon, and plating and stripping behaviors remain relatively unknown for the individual electrode/electrolyte interfaces because of the difficulty of separating the individual interfaces in a two-electrode cell configuration. Because areal capacities of practical cells target >5 mAh/cm2, it is important to cycle at much higher areal capacities than typically studied. Here, we utilize a three-electrode symmetric cell of sodium metal with sodium beta alumina (NBA) electrolyte and cycled areal capacities ranging from 0.5 to 5 mAh cm-2 and achieved current densities >10 mA cm-2 at 1.0 mAh cm-2. We find that polarization increases most at the stripping electrode, and that during current density ramps the polarizations are greatly affected by the areal capacity, affecting the maximum current density that can be reached prior to either cell shorting or impedance rise that drives the voltage magnitude to well over 1 V. Additionally, we found resistance rise occurring at the Na/NBA interface during plate (reduction) as well as strip (oxidation) for the same electrode, potentially indicating voiding on plate at sufficiently high current densities and areal capacities (5 mAh cm-2, >2 mA cm-2). For two-electrode studies, the voltage evolution on the plating electrode we observe must be considered for the assumption that the plating electrode is a pseudo reference electrode. We also use our three-electrode cell configuration to study several other experimental conditions, including cycling to failure at a fixed current density and areal capacity, as well as a uni-directional current flow experiment to determine the maximum amount of plating / stripping that can be achieved in the absence of cycling. These findings will help direct future experiments and interpretation of data to quantify the limits and improve the engineering of Li and Na metal / solid electrolytes interfaces.Jolly, D. S.; Ning, Z.; Darnbrough, J. E.; Kasemchainan, J.; Hartley, G. O.; Adamson, P.; Armstrong, D. E. J.; Marrow, J.; Bruce, P. G. Sodium/Na Β″ Alumina Interface: Effect of Pressure on Voids. ACS Appl Mater Interfaces 2019, 12 (1), 678–685. https://doi.org/10.1021/ACSAMI.9B17786.Krauskopf, T.; Hartmann, H.; Zeier, W. G.; Janek, J. Toward a Fundamental Understanding of the Lithium Metal Anode in Solid-State Batteries - An Electrochemo-Mechanical Study on the Garnet-Type Solid Electrolyte Li 6.25 Al 0.25 La 3 Zr 2 O 12. ACS Appl Mater Interfaces 2019, 11 (15), 14463–14477. https://doi.org/10.1021/ACSAMI.9B02537/SUPPL_FILE/AM9B02537_SI_001.PDF.

Enhanced electrocatalytic removal of tetracycline using dual carbon material combined particle electrodes in a three-dimensional electrochemical system: Degradation pathway and mechanism

In order to assemble low cost and high performance electrochemical oxidation system for wastewater treatment, biochar was decorated by graphene to synthesize carbon composite graphene/biochar (GBC) as particle electrode filled into a three-dimensional electrochemical reactor. The GBC particle electrodes demonstrated better electrochemical reaction activity than biochar (BC) particle electrodes. The GBC three-dimensional electrochemical reactor achieved 99.48% removal of tetracycline (5 mg/L) under an input voltage of 10 V. The electrochemical oxidation performance of GBC electrode system was competitive to some metal/metal oxides or metal/carbon material electrode system reported. The removal efficiency of tetracycline was less sensitive to the initial pH of solution from 3.0 to 11.0. The GBC electrode had higher oxygen evolution potential (OEP) (1.76 V), and lower Tafel slope (0.013 V dec−1) than that of the BC. Coated graphene improved electrical conductivity to prompt electron aggregation on surface of the biochar resulting in more reactive oxygen species (ROS) generation. The indirect electrochemical degradation of tetracycline was dominated by non-radicals pathway that singlet oxygen (1O2) rather than free radicals (·OH, O2·-) played the main role. This study proposed a new strategy to develop non-metallic particle electrodes using carbon-based materials for high efficient electrocatalytic oxidation in the electrochemical treatment system.

Enhanced Ionic Polymer-Metal Composites with Nanocomposite Electrodes for Restoring Eyelid Movement of Patients with Ptosis.

The present study aims to use enhanced ionic polymer-metal composites (IPMC) as an artificial muscle (a soft-active actuator) to restore eyelid movement of patients with ptosis. The previous eyelid movement mechanisms contained drawbacks, specifically in the lower eyelid. We used finite element analysis (FEA) to find the optimal mechanism among two different models (A and B). In addition to common electrodes of IPMC (gold and platinum), the bovine serum albumin (BSA) and microcrystalline cellulose (MCC) polymers, with optimal weight percentages of carbon nanotube (CNT) nanofiller, were also utilized as non-metallic electrodes to improve the efficiency of the IPMC actuator. In both models, IPMC with nanocomposite electrodes had higher efficiency as compared to the metallic electrodes. In model A, which moved eyelids indirectly, IPMC with MCC-CNT electrode generated a higher force (25.4%) and less stress (5.9 times) as compared to IPMC with BSA-CNT electrode. However, the use of model A (even with IPMCs) with nanocomposite electrodes can have limitations such as possible malposition issues in the eyelids (especially lower). IPMC with MCC-CNT nanocomposite electrode under model B, which moved eyelids directly, was the most efficient option to restore eyelid movement. It led to higher displacements and lower mechanical stress damage as compared to the BSA-CNT. This finding may provide surgeons with valuable data to open a window in the treatment of patients with ptosis.

Fully Flexible MXene-based Gas Sensor on Paper for Highly Sensitive Room-Temperature Nitrogen Dioxide Detection.

Flexible chemiresistive gas sensors have attracted growing interest due to their capability in real-time and rapid detection of gas. However, the performance of gas sensors has long been hindered by the poor charge transfer ability between the conventional metal electrode and gas sensing semiconductors. Herein, for the first time, a fully flexible paper-based gas sensor integrated with the Ti3C2Tx-MXene nonmetallic electrode and the Ti3C2Tx/WS2 gas sensing film was designed to form Ohmic contact and Schottky heterojunction in a single gas sensing channel. Ti3C2Tx/WS2 has outstanding physical and chemical properties for both Ti3C2Tx and WS2 nanoflakes, showing high conductivity, effective charge transfer, and abundant active sites for gas sensing. The response of the gas sensor to NO2 (1 ppm) at room temperature is 15.2%, which is about 3.2 and 76.0 times as high as that of the Au interdigital electrode integrated with the Ti3C2Tx/WS2 sensor (4.8%) and the MXene electrode integrated with the Ti3C2Tx sensor (0.2%), respectively. Besides, this design performed at a limit of detection with 11.0 ppb NO2 gas and displayed excellent stability under high humidities. Based on first-principles density functional theory calculation results, the improvement of the gas sensing performance can be mainly attributed to the heterojunction regulation effect, work function matching, and suppressing metal-induced gap states. This work provides a new approach for the design of flexible gas sensors on paper with MXene-based conductive electrodes and gas sensing materials.

Medium-independent hydrogen atom binding isotherms of nickel oxide electrodes

<h2>Summary</h2> Adsorption and transfer of hydrogen atoms at solid/solution interfaces are fundamental to heterogeneous catalysis for chemical energy transformations and other processes. Reported here are electrochemical and spectroelectrochemical measurements of the thermodynamics of H-atom binding to nickel oxide electrodes, both the average and the distribution of NiO–H bond dissociation free energies (BDFEs). These are perhaps the first measurements of binding isotherms at non-metal electrodes. Remarkably, both the BDFEs and the non-Langmuirian isotherms are the same in water, acetonitrile, and dimethylformamide, and with different buffers and proton activities. Such medium independence of the BDFEs and isotherms has not been previously reported for any binary material. The medium independence supports the common use of computed hydrogen binding energies as intrinsic descriptors of surface reactivity, while the broadened isotherms add a level of complexity to such analyses. This work demonstrates the capability to derive key thermodynamic parameters at chemically reactive solid-liquid interfaces.

Understanding the Electric Double-Layer Structure, Capacitance, and Charging Dynamics

Significant progress has been made in recent years in theoretical modeling of the electric double layer (EDL), a key concept in electrochemistry important for energy storage, electrocatalysis, and multitudes of other technological applications. However, major challenges remain in understanding the microscopic details of the electrochemical interface and charging mechanisms under realistic conditions. This review delves into theoretical methods to describe the equilibrium and dynamic responses of the EDL structure and capacitance for electrochemical systems commonly deployed for capacitive energy storage. Special emphasis is given to recent advances that intend to capture the nonclassical EDL behavior such as oscillatory ion distributions, polarization of nonmetallic electrodes, charge transfer, and various forms of phase transitions in the micropores of electrodes interfacing with an organic electrolyte or ionic liquid. This comprehensive analysis highlights theoretical insights into predictable relationships between materials characteristics and electrochemical performance and offers a perspective on opportunities for further development toward rational design and optimization of electrochemical systems.

Development of Electrostatic-Precipitator-Type Air Conditioner for Reduction of Fine Particulate Matter in Subway

This study developed a highly efficient electrostatic precipitator (ESP) type air conditioner to reduce the particulate matter (PM) concentration in a subway station. A polyethylene terephthalate film coated carbon sheet nonmetallic electrode was used as a collection plate to reduce the weight instead of the metallic collection plate, and the carbon fiber ionizer was used to minimize the ozone generation. When the flow velocity in a duct was 1 m/s with −5.0 kV applied to the ionizer and −5.0 kV to the collection plates, the 0.3- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m PM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> removal efficiency increased up to 97.47%. Holes in the collection plates were used to attach connecting tubes to maintain a constant distance. The strength and shape of the electric field were analyzed using COMSOL. The electric field quickly dissipated in the hole areas, and the field strength converged to 0. The collection plates were extended to compensate for the reduced collection area due to the holes. As a result, when the flow rate in the duct was 1 m/s, −5.0 kV was applied to the ionizer, and the electric field strength was up to −1.5 kV/mm, the PM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> removal efficiency was increased to 99.08%. This behavior resembled that of conventional collection plates. The ESP developed in this study corresponds to a higher MERV13 grade than the MERV10 grade filter currently installed in the air conditioner of the subway station and has almost no pressure drop, so it is expected to contribute to the improvement of air quality and energy efficiency of subway stations.

Simulation Study on Lightning Impulse Characteristics of Flexible Graphite Composite Grounding Materials Applied to Grounding Grid of Power System

The flexible graphite composite grounding electrode is a non-metallic grounding electrode with good electrical conductivity, corrosion resistance and non-ferromagnetic properties. In order to analyze the impulse characteristics of the graphite composite grounding electrode, this paper builds a frequency domain electrical network model and an equivalent radius iterative algorithm, considering skin effect, inductance effect, capacitance effect and spark discharge effect. The impulse characteristics of typical metal grounding electrodes and graphite composite grounding electrodes are analyzed by simulation. The research results show that: Compared with the traditional metal grounding electrode, the graphite composite grounding electrode has a smaller skin and inductance effect under the action of the impulse current, and a better current flowing capability; as the soil resistivity increases, the inductance effect and the skin effect are weakened, while the spark discharge effect is gradually enhanced and dominates. The spark discharge effect can effectively decrease the grounding resistance. The obtained critical value of the normalized parameter of 412 kA Ω, can be taken as the threshold to discriminate the conditions with dominate inductance effect from the conditions with dominant spark discharge effect.