Electrode Design Research Articles

Electro-Chemo-Mechanically Stable and Sodiophilic Interface for Na Metal Anode in Liquid-based and Solid-State Batteries.

Na metal batteries (NMBs) are attracting increasing attention because of their high energy density. However, the widespread application of NMBs is hindered by the growth of Na dendrites and interface instability. The design of artificial solid electrolyte interphase (SEI) with tuned chemical/electrochemical/mechanical properties is the key to achieving high-performance NMBs. This work develops a metal-doped nanoscale polymeric film with tunable composition, sodiophilic sites and improved stiffness. The incorporation of metal crosslinkers in the polymer chains results in exceptional electrochemical stability for Na metal anodes, leading to a significantly prolonged lifespan even at high current densities, which is at the top of the reported literature. The mechanical properties measurements and electro-chemo-mechanical phase-field model are performed to interpret the impact of the ionic transportation capability (decoupled mechanical) and mechanic property in the metal-doped polymer interface. In addition, this approach provides a promising strategy for the rational design of electrode interfaces, providing enhanced mechanical stability and improved sodiophilicity, which can open up opportunities for the fabrication of next-generation energy storage.

Flexible self‐supporting organic cathode with interface engineering for high‐performance and wide‐temperature sodium‐ion batteries

AbstractFlexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics, and organic cathode materials have become contenders for flexible self‐supporting electrodes. However, issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay. Herein, we have designed a flexible self‐supporting cathode based on perylene‐3,4,9,10‐tetracarboxylic dianhydride (PTCDA), interfacial engineering enhanced by polypyrrole (PPy), and carbon nanotubes (CNTs), forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods, effectively curbing those challenges. When used as the cathode of sodium‐ion batteries, PTCDA/PPy/CNTs exhibit excellent rate capability (105.7 mAh g−1 at 20 C), outstanding cycling stability (79.4% capacity retention at 5 C after 500 cycles), and remarkable wide temperature application capability (86.5 mAh g−1 at −30°C and 115.4 mAh g−1 at 60°C). The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ ions and carbonyl groups by density functional theory calculations, in situ infrared Fourier transform infrared spectroscopy, and in situ Raman spectroscopy. Surprisingly, the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states. This work inspires more rational designs of flexible and self‐supporting organic cathodes, promoting the development of high‐performance and wide‐temperature adaptable wearable electronic devices.

Electrode design to improve the performance of batteries

Abstract The development of electric energy effectively improved the lack of energy and the environment damage causing by fossil fuel abuse. Batteries, as a common electric power source, can be able to provide no carbon emission or polluted air compared to internal combustion engine and is now replacing them in increasing number of fields. Among them, lithium-ion batteries (LIBs) hold the highest energy density and capacity, and own the most widely usage. However, their properties are still limited and confine the LIBs being used in more extremely condition. To solve the problems, scientists are now researching on every part of the LIBs, trying to create innovation and improve the LIBs performance. This summarize focuses on electrode design, summing up 4 types of electrode material choices researched by different groups and 10 manufacturing processes. Through them, the research will conclude the method of LIBs improvement and give direction for the further research.

Solid-State Microfabricated Potentiometric Sensors for Selective Assessment of Diclofenac Sodium Utilizing Pentafluorophenyl Diazonium Modified Carbon Nanotubes Transducer Layer

In the pharmaceutical field, analytical chemistry is evolving and one area that is experiencing enthusiasm is the design and implementation of solid contact ion-selective electrodes. We have developed two potentiometric sensors for the selective assay of a widely used drug diclofenac sodium. Diclofenac sodium was targeted in one of its most recommended dosage forms (Arthrotec® tablets) in the presence of misoprostol. A cost-effective copper printed circuit board as a substrate has been coated with a PVC sensing membrane to fabricate sensor I. Hydrophobic carbon nanotubes (CNTs) have been modified through in situ reduction of pentafluorophenyl diazonium using sodium borohydride. An interlayer of the modified CNTs was inserted as a transducer layer between the Cu substrate and the ion-sensing membrane in sensor II to enhance its electrochemical performance and stability. The microfabricated electrodes demonstrated encouraging outcomes upon the direct assay of diclofenac sodium in combination with misoprostol and other additives without sample preparation steps. The responses presented a linear Nernstian pattern in the range of 1.0 × 10−4 to 1.0 × 10−2 mol l−1 with a slope of −58.2 and −58.4 mV/decade for sensors I and II, consequently. Finally, the sustainability of the developed technique was assured using advanced green metrics.

High intensity proton source based on a hollow-cathode reflex discharge.

We describe here the electrode system, design, and parameters of an ion source based on a Penning-type hollow-cathode reflex discharge developed for generation of proton beams. Especially for proton beam generation, a modified geometry of both hollow and reflex cathodes was fabricated. The working gas is molecular hydrogen. Ion extraction and beam formation are performed using a three-electrode single-aperture optical system with a 3-mm diameter emission aperture. At an accelerating voltage of 33-35kV and a discharge current of 0.55A in continuous mode, the ion beam current was 15-17 mA, and in pulsed mode, at a discharge current of about 2A, the beam current was 55 mA. The beam consists mainly of H+, H2+, and H3+ ions, with the proton (H+) fraction up to 27% in continuous mode and 40% in pulsed mode.

Soft crawling caterpillar driven by electrohydrodynamic pumps

AbstractSoft crawling robots are usually driven by bulky and complex external pneumatic or hydraulic actuators. In this work, we proposed a miniaturized soft crawling caterpillar based on electrohydrodynamic (EHD) pumps. The caterpillar was mainly composed of a flexible EHD pump for providing the driving force, an artificial muscle for performing the crawling, a fluid reservoir, and several stabilizers and auxiliary feet. To achieve better crawling performances for our caterpillar, the flow rate and pressure of the EHD pump were improved by using a curved electrode design. The electrode gap, electrode overlap length, channel height, electrode thickness, and electrode pair number of the EHD pump were further optimized for better performance. Compared with the EHD pumps with conventional straight electrodes, our EHD pump showed a 50% enhancement in driving pressure and a 60% increase in flow rate. The bending capability of the artificial muscles was also characterized, showing a maximum bending angle of over 50°. Then, the crawling ability of the soft crawling caterpillar is also tested. Finally, our caterpillar owns the advantages of simple fabrication, low‐cost, fast movement speed, and small footprint, which has robust and wide potential for practical use, especially over various terrains.

Development of improved spray system with effective electrical electrodes for aerosol removal: An experimental study in UTARTS facility

Safe reactor decommissioning, especially for damaged Fukushima Daiichi (1F) nuclear power plants, is vital for environmental safety. Key challenges include remotely cleaning radiation hotspots and cutting fuel debris within the damaged primary containment vessel. However, submicron radioactive Aerosol Particles (APs) can be generated, thus necessitating effective aerosol control and removal to avoid radioactive environmental pollution and reduce radiation exposure risks during 1F decommissioning. Flue gases containing submicron APs that result in environmental pollution can also generated from other industrial works, e.g., coal, mining and chemical sectors. Conventional water spray is difficult to scavenge these small APs. Although previous studies showed the effectiveness of charged droplets on accelerating aerosol removal, the charging configuration is also important to scavenging performance. Hence, this study performs aerosol scavenging experiments in our UTARTS facility with varying induction electrode designs. Experimental results show the saturation of scavenging efficiency at high voltage and indicate the importance of charging polarity. Moreover, proper configurations of electrode position, geometry and material are studied and discussed. Our findings can be beneficial for the improvement of spray system for aerosol removal to mitigate radioactivity release and minimize contaminated water production and have implications for gas purification in various environmental and chemical industries.

MXene and polyaniline coated 3D-printed carbon electrode for asymmetric supercapacitor

ABSTRACT 3D printing has emerged as an attractive manufacturing technique in supercapacitor electrodes owing to the precise and customisable fabrication of complex electrode designs, enhancing the performance and efficiency of the device. Despite the advantages, 3D-printed electrodes are limited by their low conductivity and electrochemical properties, predominantly due to the lack of availability of suitable conductive materials. To address this limitation, we modified the 3D-printed nanocarbon (3D-PnC) electrode by activation and surface deposition of Ti3C2Tx MXene. A solid-state asymmetric supercapacitor was fabricated by using 3D-PnC/Ti3C2Tx as the negative electrode and polyaniline (PANI) electrodeposited 3D-printed nanocarbon electrode (3D-PnC@PANI) as the positive electrode. The fabricated symmetric supercapacitor exhibits enhancement in overall voltage window, areal capacitance and energy density. The successful operation of the supercapacitor was demonstrated by the illumination of the red light-emitting diodes. Furthermore, this research opens the possibility of utilising MXene-modified 3D-printed electrodes for various electrochemical applications and devices.

FUTURE OF DEEP BRAIN STIMULATION AS A TREATMENT PROCEDURE OF NEURODEVELOPMENTAL DISORDER

Neurodevelopmental disorders, attention deficit hyperactivity disorder (ADHD), and Tourette syndrome, present challenges in understanding and treating due to their different etiologies. Since traditional treatment methods are often ineffective, new methods are sought. Originally developed as a treatment for Parkinsons disease, deep brain stimulation (DBS) has recently been recognized as a potential treatment for neurodegenerative disorders. This article provides an overview of the status and future of DBS in the treatment of neurological disorders. First, it provides an overview of neurodevelopmental disorders, highlighting differences and the urgent need for specific interventions. It is now part of the DBS method, which describes how electrical stimulation targeting specific parts of the brain changes the neural networks associated with the condition. Additionally, this book reviews preclinical and clinical studies demonstrating the feasibility and safety of DBS in relieving symptoms associated with neurological disorders. Information from neuroimaging and electrophysiological studies is combined to determine the neuropsychological implications of DBS-mediated therapeutic effects. It also describes the ability of the adaptive DBS paradigm to change dynamic parameters based on real-time activity and thus alter clinical outcomes. Additionally, this summary examines the limitations and future directions of DBS in neurodevelopmental disorders. Best practices such as patient acceptance and long-term safety are highlighted by technical challenges in electrode design and development. He also discusses integrating DBS with complementary approaches such as cognitive behavioral therapy and pharmacology to improve clinical outcomes.

Laser chemical vapor deposition of nitrogen-doped SiC electrode for electrochemical detection of uric acid

Reasonable design and construction of high-performance electrodes are desirable for developing non-enzymatic electrochemical sensors for uric acid (UA). Herein, N-doped SiC film was prepared as an electrochemical electrode using a novel laser chemical vapor deposition (LCVD) method. Compared with its undoped counterpart, the doped electrode exhibited a low detection limit of 0.77 μM and a high detection sensitivity of 9.75 µA µM−1 cm−2 owing to its large active sites and fast electron transfer rate. Furthermore, the as-developed electrode clearly exhibited immunity towards the coexisting interfering species, such as dopamine and ascorbic acid, and facilitated the quantitative analysis of UA in real-world samples. In addition, the effects of N doping on electrochemical sensing were verified via theoretical calculations by investigating adsorption energy and Bader charge. Our works verify the feasibility of introducing N into SiC to enhance UA sensing performance and fabricating on-chip electrochemical sensors, which may spur the development of advanced and portable SiC-based biosensors for health monitoring.

Sensitivity and Validation of Porous Membrane Electrical Cell Substrate Impedance Spectroscopy (PM-ECIS) for Measuring Endothelial Barrier Properties.

Measurement of endothelial and epithelial barrier integrity is important for a variety of in vitro models, including Transwell assays, cocultures, and organ-on-chip platforms. Barrier resistance is typically measured by trans-endothelial electrical resistance (TEER), but TEER is invasive and cannot accurately measure isolated monolayer resistance in coculture or most organ-on-chip devices. These limitations are addressed by porous membrane electrical cell-substrate impedance sensing (PM-ECIS), which measures barrier integrity in cell monolayers grown directly on permeable membranes patterned with electrodes. Here, we advanced the design and utility of PM-ECIS by investigating its sensitivity to working electrode size and correlation with TEER. Gold electrodes were fabricated on porous membrane inserts using hot embossing and UV lithography, with working electrode diameters of 250, 500, and 750 μm within the same insert. Sensitivity to resistance changes (4 kHz) during endothelial barrier formation was inversely proportional to electrode size, with the smallest being the most sensitive (p < 0.001). Similarly, smaller electrodes were most sensitive to changes in impedance (40 kHz) corresponding to cell spreading and proliferation (p < 0.001). Barrier disruption with both EGTA and thrombin was detectable by all electrode sizes. Resistances measured by PM-ECIS vs TEER for sodium chloride solutions were positively and significantly correlated for all electrode sizes (r > 0.9; p < 0.0001), but only with 750 μm electrodes for endothelial monolayers (r = 0.71; p = 0.058). These data inform the design and selection of PM-ECIS electrodes for specific applications and support PM-ECIS as a promising alternative to conventional TEER for direct, noninvasive, real-time assessment of cells cultured on porous membranes in conventional and organ-on-chip barrier models.

Lithium Plating Characteristics in High Areal Capacity Li-Ion Battery Electrodes.

Li-ion battery degradation and safety events are often attributed to undesirable metallic lithium plating. Since their release, Li-ion battery electrodes have been made progressively thicker to provide a higher energy density. However, the propensity for plating in these thicker pairings is not well understood. Herein, we combine an experimental plating-prone condition with robust mesoscale modeling to examine electrode pairings with capacities ranging from 2.5 to 6 mAh/cm2 and negative to positive (N/P) electrode areal capacity ratio from 0.9 to 1.8 without the need for extensive aging tests. Using both experimentation and a mesoscale model, we identify a shift from conventional high state-of-charge (SOC) type plating to high overpotential (OP) type plating as electrode thickness increases. These two plating modes have distinct morphologies, identified by optical microscopy and electrochemical signatures. We demonstrate that under operating conditions where these plating modes converge, a high propensity of plating exists, revealing the importance of predicting and avoiding this overlap for a given electrode pairing. Further, we identify that thicker electrodes, beyond a capacity of 3 mAh/cm2 or thickness >75 μm, are prone to high OP, limiting negative electrode (NE) utilization and preventing cross-sectional oversizing the NE from mitigating plating. Here, it simply contributes to added mass and volume. The experimental thermal gradient and mesoscale model either combined or independently provide techniques capable of probing performance and safety implications of mild changes to electrode design features.

Enhanced electroactive bacteria enrichment and facilitated extracellular electron transfer in microbial fuel cells via polydopamine coated graphene aerogel anode

The structure and surface physicochemical properties of anode play a crucial role in microbial fuel cells (MFCs). To enhance the enrichment of exoelectrogen and facilitate extracellular electron transfer (EET), a three-dimensional macroporous graphene aerogel with polydopamine coating was successfully introduced to modify carbon brush (PGA/CB). The three-dimensional graphene aerogel (GA) with micrometer pores improved the space utilization efficiency of microorganisms. Polydopamine (PDA) coating enhanced the physicochemical properties of the electrode surface by introducing abundant functional groups and nitrogen-containing active sites. MFCs equipped with PGA/CB anodes (PGA/CB-MFCs) demonstrated superior power generation compared to GA/CB-MFCs and CB-MFCs (MFCs with GA/CB and CB anodes respectively), including a 23.0 % and 30.1 % reduction in start-up time, and an increase in maximum power density by 2.43 and 1.24 times respectively. The higher bioelectrochemical activity exhibited by the biofilm of PGA/CB anode and the promoted riboflavin secretion by PGA modification imply the enhanced EET efficiency. 16S rRNA high-throughput sequence analysis of the biofilms revealed successful enrichment of Geobacter on PGA/CB anodes. These findings not only validate the positive impact of the synergistic effects between GA and PDA in promoting EET and improving MFC performance but also provide valuable insights for electrode design in other bioelectrochemical systems.

Studies on the reduction of dispersed emissions from a low-power household boiler in a plasma ionic wind zone

Gas ionizator is a device for electrostatic precipitation and is widely used to separate fine particulate matter (FPM) from small- and large-scale industrial exhaust gases. Two variations of electrodes design, rod and rectangle-toothed saw were used. The mass and number concentrations of six FPM fractions were detected. Stronger vortices occur at higher EAD/Re2 ratios compared to the secondary electroaerodynamic (EAD) gas velocities. A deposition efficiency higher than 94.9 % was achieved at a gas velocity of 0.2 m/s. The FPM capture efficiency at voltage up to 20 kV is higher more than 7 % than at a voltage of 15 kV.

Insertion trauma and functional recovery after cochlear implantation

The cochlear implant is considered one of the most successful medical devices. The efficiency and cost-effectiveness of implants making a difference in the life of a person with hearing loss is well recognized. There are approximately 750,000 implant patients worldwide. While implant technology is advancing and clinical indications continue to expand, the focus is increasingly shifting towards improving outcomes and enhancing the quality of patient care. Of particular relevance today is the preservation of delicate intracochlear structures during implant surgery, which provides the best prerequisite for successful hearing rehabilitation. In this regard, the article is devoted to the consideration of peculiarities and methods of detection of tissue traumatization during cochlear implantation, as well as the possibilities of functional recovery after implantation. The methodological basis of the study is a systematic literature search, which was conducted using PubMed Medline, methods of analysis, synthesis, generalization, and grouping, investigation of the results of radiological and histological studies. The analysis describes the possibilities and potential of using contrast-enhanced micro-CT with simultaneous application of a special polyoxometalate staining agent to analyze cochlear implant injuries. Special attention is paid to the prospects of using a robotic surgical instrument that assists the surgeon in the insertion of the electrode array. The advantage of using the growth function of the amplitude of the evoked compound action potential to assess functional responses to electrical stimulation of the cochlea is also noted. Further studies of the geometry of intracochlear structures and compartments will allow developing new and improved electrode designs and introducing atraumatic surgical techniques for cochlear implant insertion.

Redesigned Electrodes for Improved Intraoperative Nerve Conduction Studies during the Treatment of Peripheral Nerve Injuries.

Traumatic peripheral nerve injuries (PNI), present with symptoms ranging from pain to loss of motor and sensory function. Difficulties in intraoperative visual assessment of nerve functional status necessitate intraoperative nerve conduction studies (INCSs) by neurosurgeons and neurologists to determine the presence of functioning axons in the zone of a PNI. This process, also referred to as nerve "inching", uses a set of stimulating and recording electrode hooks to lift the injured nerve from the surrounding surgical field and to determine whether an electrical stimulus can travel through the zone of injury. However, confounding electrical signal artifacts can arise from the current workflow and electrode design, particularly from the mandatory lifting of the nerve, complicating the definitive assessment of nerve function and neurosurgical treatment decision-making. The objective of this study is to describe the design process and verification testing of our group's newly designed stimulating and recording electrodes that do not require the lifting or displacement of the injured nerve during INCSs. Ergonomic in vivo analysis of the device within a porcine model demonstrated successful intraoperative manipulation of the device, while quantitative nerve action potential (NAP) signal analysis with an ex vivo simulated "inching" procedure on healthy non-human primate nerve tissue demonstrated excellent reproducible recorded NAP fidelity and the absence of NAP signal artifacts at all points of recording. Lastly, electrode pullout force testing determined maximum forces of 0.43 N, 1.57 N, and 3.61 N required to remove the device from 2 mm, 5 mm, and 1 cm nerve models, respectively, which are well within established thresholds for nerve safety. These results suggest that these new electrodes can safely and successfully perform accurate PNI assessment without the presence of artifacts, with the potential to improve the INCS standard of care while remaining compatible with currently used neurosurgical technology, infrastructure, and clinical workflows.

NxCyMz metal hydroxide with Br− intercalation for high-performance structural supercapacitors

The rational design of advanced structural electrodes with superior electrochemical capacitive properties is one of the crucial hindrances be overcome for high energy density all-solid-state structural supercapacitors (ASSC). Herein, a simple synthesis of flower-like NxCyMz-layered metal hydroxides with high performance on nickel foam (NF) was proposed. Br− was inlaid to NxCyMz as a modified anion for the first time (denoted as B-N3C1M0.5-6U-1Br−). Compared with N3C1M0.5, the electrochemical performance of B-N3C1M0.5-6U-1Br− has been significantly enhanced. It reaches a maximum areal capacitance of 16.2 F/cm2 at 10 mA/cm2 and maintains a high capacitance retention of 11.6 F/cm2 even at a current density of 50 mA/cm2. Furthermore, the assembled asymmetric ASSC with B-N3C1M0.5-6U-1Br− as the positive electrode achieves a high areal energy density of 135.47 μWh/cm2 at a power density of 2250 μW/cm2. More importantly, six fully charged ASSCs with a total volume of 3 cm3 connected in series can power a temperature and humidity indicator successfully for approximately 18 min. These results demonstrate the good application potential of our B-N3C1M0.5-6U-1Br− electrode in buildings.

Enhanced stability in pseudocapacitors: Synthesis and characterization of a novel cathode material incorporating cinnamate and ferrocenyl functional groups

This study reports the synthesis of a novel block copolymer, PEO-PFc-PCA, comprising cinnamic acid and ferrocene units via Atom Transfer Radical Polymerization (ATRP), and its application as a positive electrode material in pseudocapacitors. Ferrocene functions as redox-active sites for energy storage, while cinnamic acid, when crosslinked under UV light, forms a nano-network that reduces ferrocene leaching, thereby enhancing the stability and lifespan of the pseudocapacitors. Comprehensive structural characterization, including nuclear magnetic resonance and UV–visible spectroscopy, was conducted on PEO-PFc-PCA. Electrochemical tests—cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy—revealed that UV crosslinking improved the electrochemical performance, indicated by a slight increase in current and extended charging plateaus. Specific capacitance and energy density increased by 10 % post-crosslinking, demonstrating improved energy storage capacity. Nyquist plots showed reduced internal and charge transfer resistance after crosslinking, enhancing the electrochemical pathway. Stability tests indicated that crosslinked PEO-PFc-PCA retained 90.1 % of its capacitance after 3000 cycles, compared to 86.6 % pre-crosslinking, highlighting its superior longevity. This research presents a promising approach to enhancing pseudocapacitor energy storage through cinnamic acid photopolymerization, potentially benefiting broader pseudocapacitive electrode designs.

Superior syngas product control of La(Sr)Fe(Mn)O3 perovskite in high-temperature CO2/H2O co-electrolysis

Designing a highly efficient fuel electrode for CO2/H2O co-electrolysis with controllable CO/H2 ratios is fundamentally challenging due to the significant influence of water-gas shift (WGS) reaction. Perovskite oxide La0.6Sr0.4Fe0.8Mn0.2O3 (LSFM) has been identified as a promising alternative to conventional Ni-based cermet electrodes, offering inherent redox stability. In this study, LSFM exhibits efficient electrocatalytic activity and remarkable syngas control, with ratios directly controlled by adjusting the CO2/H2O feed. In-situ/ex-situ catalytic analyses reveal LSFM’s efficacy in controlling syngas, attributed to substantial CO2 adsorption on its surface. The carbonated surface interacting with H2O leads to the formation of bicarbonate species, acting potential active intermediates that facilitate CO2 electroreduction to CO while suppressing the WGS reaction. Stable syngas control is confirmed by long-term reversible operations at various applied currents with nearly 100 % Faradaic efficiency. This study highlights the great potential of LSFM perovskite for efficient and steady syngas production in co-electrolysis, providing insights into advanced fuel electrode design.

Design, Fabrication, and Evaluation of 3D Biopotential Electrodes and Intelligent Garment System for Sports Monitoring.

This study presents the development and evaluation of an innovative intelligent garment system, incorporating 3D knitted silver biopotential electrodes, designed for long-term sports monitoring. By integrating advanced textile engineering with wearable monitoring technologies, we introduce a novel approach to real-time physiological signal acquisition, focusing on enhancing athletic performance analysis and fatigue detection. Utilizing low-resistance silver fibers, our electrodes demonstrate significantly reduced skin-to-electrode impedance, facilitating improved signal quality and reliability, especially during physical activities. The garment system, embedded with these electrodes, offers a non-invasive, comfortable solution for continuous ECG and EMG monitoring, addressing the limitations of traditional Ag/AgCl electrodes, such as skin irritation and signal degradation over time. Through various experimentation, including impedance measurements and biosignal acquisition during cycling activities, we validate the system's effectiveness in capturing high-quality physiological data. Our findings illustrate the electrodes' superior performance in both dry and wet conditions. This study not only advances the field of intelligent garments and biopotential monitoring, but also provides valuable insights for the application of intelligent sports wearables in the future.