Polymer Electrodes Research Articles

Supercapacitive MnO2/PEDOT: PSS Modified 3D-Printed Polymeric Micro-Pillar Electrode for Extraction of Photosynthetic Electrons

Photosynthetic bio-electrochemical cells (PBECs) have been reported as having promising potential for the renewable energy field. When photosynthesis occurs, photosynthetic electrons (PEs) were generated and excited in photosystem II by sunlight. These PEs were transferred via photosynthetic apparatuses in thylakoid membranes (TMs) and finally consumed to reduce NADP. So far, several attempts have been made to maximize the extraction of PEs from the TMs. Firstly, a micro-pillar electrode was demonstrated to enhance PEs extraction by maximizing the contact area with TMs [1]. As another study, for effective electrical connections with TMs, carbon nanotubes (CNTs) [2], or graphene oxide (GO) [3] were utilized to enhance PEs harvesting. Furthermore, supercapative materials were exploited to improve the performance of TM-based PBECs. For instance, PEs harvesting was enhanced in Au electrode modified with ruthenium dioxide (RuO2) nanosheets compared to a pristine Au electrode [4]. In another study, a dual-feature electrode of Au and PEDOT was introduced to collect and store PEs [5]. Although there were various attempts to harvest PEs effectively, their electrodes were still limited to the two-dimension. Thus, it is required that a three-dimensional electrode with supercapacitance to achieve more efficient PEs harvesting for practical application.In this work, we propose a supercapacitive MnO2/PEDOT:PSS-modified 3D-printed polymeric micro-pillar electrode to efficiently collect and spontaneously store the PEs. For the maximization of PE harvesting, diameter, pitches (center to center), and aspect ratio (A/R) of the micro-pillars were controlled. To fabricate the current collection layer, Au was sputtered on the 4-aminothiophenol coated stereolithographically (SLA) printed micro-pillar substrate. PEDOT:PSS was electrodeposited as secondary current collect and adhesion layer between Au and MnO2. Then, MnO2 was electrochemically deposited on PEDOT:PSS layer for efficient attachment with TMs and storage of PEs. Finally, TMs were carefully dip-coated on MnO2/PEDOT:PSS micro-pillar electrode. The morphology of each step in the electrode fabrication was analyzed by optical microscopy and scanning electron microscopy (SEM). The enhanced electrochemical surface area (ECSA) of 3D-printed MnO2/PEDOT:PSS micro-pillar electrode was compared to flat electrode using cyclic voltammetry (CV). The capacitive performance of 3D-printed TM/MnO2/PEDOT:PSS micro-pillar electrode was carefully analyzed using CV and Galvano charge-discharge measurements. Measured ECSA of MnO2/PEDOT:PSS micro-pillar electrode was 5 folds increase than that of flat electrode. MnO2/PEDOT:PSS micro-pillar electrode was achieved 4 folds and 180 folds larger than PEDOT:PSS and Au micro-pillar electrode, respectively. 212 F/g of gravimetric and 257 mF/cm2 of areal capacitance were measured in 3D-printed MnO2/PEDOT:PSS micro-pillar electrode. It was confirmed that PEs can be electrochemically extracted from TM deposited 3D-printed MnO2/PEDOT:PSS micro-pillar electrode using CV. To measure a light-triggered PE current, a standard three electrode system was configured with a 3D-printed TM/MnO2/PEDOT:PSS micro-pillar electrode. The light-driven PE current of 27 μA/cm2 was measured in a 3D-printed MnO2/PEDOT:PSS micro-pillar electrode under 100 mW/cm2 of illumination with a bias potential of 0.5 V versus Ag/AgCl.

P-Tau Dephosphorylation Measurement on the Basis of Biomimetic Electrochemical-Polymerized Thin Film Modified Eqcm

Alzheimer’s disease (AD) is characterized by the abnormal protein deposit in the brain, as a most general neurodegenerative disorder in senior. Microtubule-associated tau protein was regarded as a critical biomarker for AD in recent years due to its post-translational modification, especially hyper-phosphorylated tau protein, which would render the protein aggregation and result in neuron degeneration and paired helical filaments (PHF) formation [1]. Unbalanced activities between kinase and phosphatase are the main reason of tau protein hyper-phosphorylation, including overexpression of kinase. Research has recorded that kinases inhibitor would reverse the hyper-phosphorylation induced pathology, showing the possible therapeutic strategy with adjusting the amount of phosphorylated sites. However, this indirect method is insufficient to reverse the neurofibrillary tangle and PHF aggregation [2]. A highly effective method of reversing hyper-phosphorylation need to be investigated. Furthermore, to control the phosphorylation of tau protein, a material with good interaction with biomolecules is required.In this study, polyaniline (PANI), as one of organic conducting polymers [3], was selected due to its fascinating properties and unparalleled multifunction, including good interaction with proteins, controllable electrical conductivity, ideal stability during electrochemical reactions, and changeable nanostructures, could meet above demands and offer further more bio-applications [4]. Through the electrochemical reaction-driven exchange of ions during oxidation and reduction, PANI mimics change in functional biological organs [5] and plays a key role to create a state-of-the-art biomimetic hippocampus.A new in vitro experimental architecture was developed based on electrical quartz crystal microbalance (EQCM). First, tau protein was adsorbed on PANI-modified electrodes by electrostatic interaction to mimic captured process on the hippocampus. Then, both the constant-potential method (current-time curve) and Cyclic Voltammetry (CV) were introduced to investigate the electrochemically-driven dephosphorylation-related process and mechanism following the found optimal potential and stimulation time.As the result, the feasibility of electrochemically-driven dephosphorylation was confirmed. By establishing the relationship between resonant frequency and mass change, this hippocampus-inspired biomimetic polymeric EQCM electrode could detect a trace amount of phosphate and whole protein adsorbed and desorbed to explore the possibility of a non-invasive therapeutic strategy for AD.[1]Alonso, A. D. C., Grundke-Iqbal, I., & Iqbal, K. "Alzheimer's disease hyperphosphorylated tau sequesters normal tau into tangles of filaments and disassembles microtubules," Nature medicine, 2(7), 783-787. (1996).[2]Engel, T., Goñi‐Oliver, P., Lucas, J. J., Avila, J., & Hernández, F., "Chronic lithium administration to FTDP-17 tau and GSK‐3β overexpressing mice prevents tau hyperphosphorylation and neurofibrillary tangle formation, but pre-formed neurofibrillary tangles do not revert," Journal of neurochemistry, 99(6), 1445-1455. (2006).[3]Higgins, M. J., Molino, P. J., Yue, Z., & Wallace, G. G. (2012). Organic conducting polymer–protein interactions. Chemistry of Materials, 24(5), 828-839.[4]Huang, L., Hu, J., Lang, L., Wang, X., Zhang, P., Jing, X., ... & Wei, Y. (2007). Synthesis and characterization of electroactive and biodegradable ABA block copolymer of polylactide and aniline pentamer. Biomaterials, 28(10), 1741-1751.[5] Higgins, M. J., Molino, P. J., Yue, Z., & Wallace, G. G. (2012). Organic conducting polymer–protein interactions. Chemistry of Materials, 24(5), 828-839. Figure 1

Reactant Transport Engineering Approach at Cathode to High Power Direct Methanol Hydrogen Peroxide Fuel Cell

The development of high-power fuel cells could advance the electrification of the transportation sector, including marine and air transport. Liquid-fueled fuel cells are particularly attractive for such applications as they obviate the issue of fuel transportation and storage. Herein, we report a direct methanol hydrogen peroxide fuel cell (DMHPFC) for high-power propulsion applications that delivers 0.8 W cm2 peak power density by using a pH gradient-enabled microscale bipolar interface (PMBI) to effectively meet the incongruent pH requirements for methanol oxidation/peroxide reduction reactions.DMHPFCs are an important alternative to hydrogen-fed polymer electrode membrane fuel cell (PEMFCs) and anion exchange membrane fuel cells (AEMFCs) due to methanol’s high energy density compared to that of hydrogen and superior kinetics of hydrogen peroxide reduction reaction as compared to Oxygen. A unit volume of Hydrogen gas stored at a pressure of approximately 69 MPa corresponds to volume-specific energy density of roughly 2.1 kWh/l while 39% volume of aqueous methanol and 41% volume of aqueous hydrogen peroxide corresponds to volume-specific energy density of 9.2 kWh/l. So, DMHPFC’s energy density is approximately four times higher than hydrogen fuel cell’s energy density and is comparable to gasoline which contains roughly 9.2 kWh/l of available bond energy. The theoretical potential for Methanol oxidation reaction (MOR) in basic medium is lower than that in an acidic medium (-0.78 V vs. -0.02 V) and the theoretical potential for the Hydrogen peroxide reduction reaction (HPRR) is higher than that for oxygen reduction (1.77 V vs. 1.23 V in acidic medium). This results in the highest theoretically possible cell voltage for cells with alkaline anodes and acidic cathodes. We achieved sustained operation of the DMHPFC with an alkaline anode and an acidic cathode by incorporating our pH-gradient-enabled microscale bipolar interface (PMBI).However, the system exhibits a relatively low Faradaic efficiency of 50% due to the parasitic evolution of O2 by the decomposition of H2O2. The O2 evolution results in a mixed potential at the cathode due to the occurrence of both the HPRR (E0 = 1.77 V versus standard hydrogen electrode [SHE]) and the oxygen reduction reaction (ORR); (E0 = 1.23 V versus SHE), lowering the overall cell potential. The O2 surface coverage reduces the available sites for the HPRR, effectively deactivating the catalyst. Electrocatalysts exhibiting a combination of high HPRR activity and selectivity (by inhibiting H2O2 decomposition, and hence inhibiting ORR) would result in higher faradic efficiency and have been the subject of sustained interest. Here, we examine an alternate reactant-transport engineering approach to improve the overall cell potential and cell performance of the DMHPFC. Our reactant-transport engineering approach has examined the impact of reactant flowrate, flow velocity, residence time, and flow regime (via the Reynolds number ([Re]) on DMHPFC performance. Balancing the competing demands of high residence time to improve Hydrogen peroxide reduction reaction (HPRR) rates with high flowrates to detach adsorbed O2, we identify a critical Re and Damkholer number (Da) to efficiently exclude O2 gas bubbles while maintaining large current densities during the operation of a DMHPFC. Reactant-transport engineering of the cathode flow field architecture and fuel flowrates mitigates parasitic hydrogen peroxide decomposition and oxygen reduction reactions and lessens cathode passivation by oxygen bubbles. DMHPCs fulfilling these criteria provide a power density of >500 mW cm-2 at 1.0 V compared to state-of-the-art polymer electrolyte membrane fuel cells (PEMFCs) that typically operate at 0.75 V. The high peak power density of 800 mW cm-2 at 1.1 V may offer a pathway to reduce fuel cell stack size for propulsion applications. Our work paves the way for such other liquid fuel cells with hydrogen peroxide as the oxidant and enabled with PMBI resulting in significantly improvement in the performance. Figure 1

Stable Hexaazatrinaphthalene-Based Planar Polymer Cathode Material for Organic Lithium-Ion Batteries.

Organic materials have garnered intensive focus as a new group of electrodes for lithium-ion batteries (LIBs). However, many reported organic electrodes so far still exhibit unsatisfying cycling stability because of the dissolution in the electrolytes. Herein, a novel azo-linked hexaazatrianphthalene (HATN)-based polymer (AZO-HATN-AQ) is designed and fabricated by the polymerization of trinitrodiquinoxalino[2,3-a:2',3'-c]phenazine (HATNTN) and 2,6-diaminoanthraquinone (DAAQ). The abundant redox-active sites, extended π-conjugated planar conformation, and low energy gap endow the AZO-HATN-AQ electrode with high theoretical capacity, excellent solubility resistance, and fast Li-ion transport. In particular, the fully lithiated AZO-HATN-AQ still keeps the planar structure, contributing to the excellent cycling stability. As a result, AZO-HATN-AQ cathodes show high specific capacity (240 mAh g-1 at 0.05 A g-1), prominent rate capability (98 mAh g-1 at 8 A g-1), and outstanding cycling stability (120 mAh g-1 after 2000 cycles at 4 A g-1 with 85.7% capacity retention) simultaneously. This study demonstrates that rational structure design of the polymer electrodes is an effective approach to achieving excellent comprehensive electrochemical performance.

(Invited) Solid-State Biophotoelectronics Using Photosystem I

For the Grahame Award Symposium Photosystem I (PSI) is one of the primary macromolecular machines that drive photosynthesis in green plants and cyanobacteria. Extracted PSI has been employed successfully as a macromolecular photosensitizer within a host of low-cost electrochemical and solid-state photovoltaic architectures. This presentation will also explore our group’s recent efforts to integrate PSI with advanced nanomaterials, including carbon nanotubes, carbon quantum dots, and conducting polymers polyaniline (PANI), polypyrrole, polyviologens, and poly(3,4-ethylenedioxythiophene) in wet photoelectrochemical cells. These composite assemblies enhance charge shuttling processes from individual proteins within multilayer assemblies—greatly reducing charge transfer resistances and improving overall efficiency of photocells. Recently, our group has reported two new prototype solid-state devices in which PSI or PSI/PANI is sandwiched between conducting polymer electrodes. The group has also succeeded in stabilizing PSI films via crosslinking to create “wet” photoelectrochemical cells with greater performance and longevity. Finally, our current work is aimed at building new prototypes using PSI in solid state interfaces for scalable solar energy conversion. Finally, the incorporation of PSI into conducting polymer frameworks holds promise for improved conductivity and orientational control in the photoactive layers in these devices.

Oxygen Reduction on Organic Mixed Ionic-Electronic Conducting Polymer Electrodes

Organic mixed ionic-electronic conductors (OMIECs) are a class of conjugated semiconducting polymers with tunable electronic and ionic transport properties enabled through polaron-forming ion insertion redox reactions. The energy to form these conductive polaronic states can be controlled through rational design of the polymer backbone to enable predominantly electron/cation (n-type) or hole/anion (p-type) transport. Simultaneously, electrolyte uptake into the bulk of the electrode can be controlled through incorporation of polar/non-polar sidechains. The ability to tune the energy of the redox-active states, the majority charge carrier, and the local reaction environment offers an opportunity to independently optimize activity and selectivity in electrochemical energy conversion processes with a single-phase electrode.In this talk, I will discuss our efforts to develop OMIECs as electrocatalysts for the oxygen reduction reaction. The electronic and chemical origins of reactivity are interrogated through pH-dependent electroanalytical characterization, operando spectroscopy, charge-transport measurements, and ab initio/microkinetic simulations. The nature of the polaronic states provide a generalized framework to understand pathway selectivity towards the 2-electron H2O2 or 4-electron H2O product and serve as a design principle in developing this emerging class of metal-free electrocatalysts.

Redox-Active Ferrocene Polymer for Electrode-Active Materials: Step-by-Step Synthesis on Gold Electrode Using Automatic Sequential Polymerization Equipment.

Redox-active polymers have garnered significant attention as promising materials for redox capacitors, which are energy-storage devices that rely on reversible redox reactions to store and deliver electrical energy. Our focus was on optimizing the electrochemical performance in the design and synthesis of redox-active polymer electrodes. In this study, a redox-active polymer was prepared through step-by-step synthesis on a gold electrode. To achieve this, we designed an automatic sequential polymerization equipment that minimizes human intervention and enables a stepwise polymerization reaction. The electrochemical properties of the polymer gold electrodes were investigated. The degree of polymerization of the polymer grown on the gold electrode can be controlled by adjusting the cycle of the sequential operation. As the number of cycles increases, the amount of accumulated charge increases proportionally, indicating the potential for enhanced electrochemical performance.

Large-scale production of 18650 cylindrical supercapacitors: Effects of separators, electrode thickness, electrolyte additives, and testing protocols

Although supercapcitors have been widely studied, large-scale 18650 cylindrical supercapacitor cells have been rarely investigated and reported. Here, we investigated the effects of polymer separators, electrode thickness, electrolyte additives, testing protocols, reproducibility, and stability of the supercapacitors at the large-scale pilot plant. The supercapacitor cells with polyethylene (PE) and Al2O3-coated PE separators are good at low and high specific currents, respectively. The Al2O3-coated PE exhibits better stability than the one with the PE separator. The supercapacitor with a thickness of 250 μm has a cell capacitance of over 120 F from 100 to 1000 mA, which is higher than that of the other cells studied in this work. Also, the cell capacitances of supercapacitors can be enhanced by having redox mediator additives. 25 mM hydroquinone and ferrocene methanol are the optimized concentrations. We also found that the cell capacitance and equivalent series resistance of the supercapacitors are sensitive to the testing protocol, for which the highest capacitance was observed using the IEC62391-1 standard method, followed by the Maxwell method and conventional galvanostatic charge discharge method without dwell time. High reproducibility and stability of the as-fabricated supercapacitors in this work may lead to the further development of practical large-scale supercapcitors in the future.

Soft and stretchable organic bioelectronics for continuous intraoperative neurophysiological monitoring during microsurgery.

In microneurosurgery, it is crucial to maintain the structural and functional integrity of the nerve through continuous intraoperative identification of neural anatomy. To this end, here we report the development of a translatable system leveraging soft and stretchable organic-electronic materials for continuous intraoperative neurophysiological monitoring. The system uses conducting polymer electrodes with low impedance and low modulus to record near-field action potentials continuously during microsurgeries, offers higher signal-to-noise ratios and reduced invasiveness when compared with handheld clinical probes for intraoperative neurophysiological monitoring and can be multiplexed, allowing for the precise localization of the target nerve in the absence of anatomical landmarks. Compared with commercial metal electrodes, the neurophysiological monitoring system allowed for enhanced post-operative prognoses after tumour-resection surgeries in rats. Continuous recording of near-field action potentials during microsurgeries may allow for the precise identification of neural anatomy through the entire procedure.

Volumetric Electron Transfer from Metabolites to Chemically Doped Polymer Electrodes

AbstractThe development of sensor electrode materials for the detection of metabolites will enable point‐of‐care diagnostic devices for the monitoring and treatment of metabolic diseases such as diabetes. Current state‐of‐the‐art glucose sensing electrodes employ the organic salt tetrathiafulvene tetracyanoquinodimethane (TTF TCNQ) to receive electrons directly from enzymatic reactions of glucose. However, TTF TCNQ is insoluble in most solvents, making it challenging to deposit high‐quality electrodes. Furthermore, its hydrophobicity hinders its interface with aqueous solutions in physiological environments. To overcome these issues, TCNQ derivatives are introduced into an electron‐rich and hydrophilic conjugated polymer. Thus, a polymeric electrode is demonstrated that is easily solution processible and can undergo volumetric direct electron transfer with glucose reactions throughout its bulk. This study further elucidates the electron transfer mechanism during chemical doping and metabolite sensing reactions to inform general design rules for this new class of glucose sensing materials.

Interwoven of γ-MnO2 and V2O5 nanostructures with polyindole grafted reduced graphene oxide nano-platform for high-efficient supercapacitors: A collaborated insight of experimental and surface morphological studies

The continuous evolution toward high-yield electronic devices with green and mechanical robust properties offers an emerging demand for polymeric nanocomposite electrodes. Herein, an efficient in-situ electro-synthesized route was pursued in designing novel reduced graphene oxide/polyindole (rGO/PIND) nanocomposite electrodes decorated by γ-MnO2 and V2O5 nanostructures. A nanosecond fiber laser was applied to synthesize V2O5 nanoparticles through laser ablation in liquid (LAL) technique and γ-MnO2 nanostructure was constructed by a solid-state reaction method. The fabricated electrodes were characterized by physical and electrochemical methods. To investigate the effect of the surface morphological features on the electrochemical (EC) performance of nanocomposite electrodes the surface statistical, Areal Autocorrelation Function (AACF), and fractal studies were carried out by using AFM analysis. These studies revealed the presence of nanoparticles results in more compactness and well-developed surface morphology with more roughness and irregularity. The electrochemical study of the design electrodes was performed in three and two-electrode setups. Two asymmetric supercapacitors (ASCs) of rGO//rGO/PIND/V2O5, rGO//rGO/PIND/γ-MnO2 were fabricated and characterized by physical and electrochemical methods. The rGO//rGO/PIND/γ-MnO2 ASSC device provided a superior specific capacitance (CS) of 165F g−1, energy density of 51.5 Wh kg−1, and power density of 3.7 kW kg−1 at 5.0 A g−1 with 95.7% retention of CS after 10,000 cycles and with a broad 1.50 V potential window. Additionally, the rGO/PIND/γ-MnO2//rGO/PIND/γ-MnO2 symmetric supercapacitor (SSC) device exhibited 28.5 Wh kg−1 energy density, and 6.8 kW kg−1 power density at 5.0 A g−1 with 92.8% retention capacitance after 10,000 cycles.

Effect of sulfated/carboxylated cellulose nanocrystals with different degrees of substitution on the morphology and electrochemical performance of polypyrrole electrodes

As a result of different extraction methods, CNCs bear different surface groups with different degrees of substitution (DS), which may affect the electrode properties when incorporated as the reinforcing template in conducting polymer electrodes. After depositing polypyrrole (PPy) electrodes with different CNCs as dopants, we found that the PPy/CNCs electrode structure and electrochemical performance were sensitive to the DS of CNCs sulfate groups, while variation in the DS of carboxylates did not have any significant effect. PPy/CNCs electrodes deposited with carboxylated CNCs and a low sulfate group DS showed a porous and interconnected structure, while PPy/CNCs electrodes deposited with carboxylated CNCs with a high sulfate DS had a dense structure. Higher areal capacitance, higher rate capability, and smaller resistance were achieved with PPy/CNCs electrodes deposited using CNCs bearing carboxylates and a low DS of sulfate groups on CNCs. Cycling studies showed that porous electrodes reduced their charge storage capacity over 3000 cycles, however, dense PPy electrodes prepared using high-sulfate DS CNCs increased their charge storage capacity by 715% (from 0.15 to 1.07 F cm−2) over the first 1200 cycles showing opening of the structure and better electrolyte perfusion. This capacitance then stayed constant for at least another 1700 cycles.

Hydrogen evolution performance of a Ag(I) bis(benzimidazole) coordination polymer doped carbon paste composite electrode

A new Ag(I) coordination polymer, [Ag2(BBO)]n, H2BBO = 1,3-bis(benzimidazol-2-yl)-2-oxopropane, was synthesized by diffusion method and characterized. The structural analysis showed that the Ag(I) coordination polymer has a 2D layered structure, and each polymerization unit is composed of two BBO ligands and four Ag(I) ions, which form two types of structures (border silvers and center silvers). The hydrogen evolution reaction (HER) performance of the composite electrode CE-Ag formed by mixing the Ag(I) coordination polymer and carbon paste electrode was investigated by linear scanning voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results showed that the overpotential (η10 298) of the obtained CE-Ag was positively shifted by 320 mV when the current density reached 10 mA cm−2 compared with the blank electrode (CE) and the Tafel slope of the CE-Ag was 158 mV dec−1. These indicated that CE-Ag was effective for the HER electrocatalytic reaction. In addition, the smaller charge transfer resistance Rct (40 Ω) of CE-Ag compared with that of CE (2263 Ω) further indicates the effective catalytic capacity of the Ag(I) coordination polymer for hydrogen evolution. The information obtained from this study will help to expand the application of Ag(I) coordination polymers in the field of electrochemistry.

Flexible all-organic photodetectors via universal water-assisted transfer printing

Transfer printing of small-molecular organic semiconductors often faces challenges due to surface adhesion mismatch. Here, we developed a sacrificing-layer-assisted transfer printing technique for the deposition of small-molecular thin films. High-boiling-point ethylene glycol (EG) was doped in aqueous solution poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) as the sacrificing layer to manipulate residual water in film, which allowed chlorobenzene solution to spontaneously spread and form uniform film. The residual water guaranteed film delamination from the stamp, allowing for its transfer onto various substrates and seeding layers. As a proof of concept, laterally conductive organic photodetectors using recyclable EG-PEDOT:PSS electrodes and a small-molecular active layer were consecutively fabricated via transfer printing in ambient air. The resulting device exhibited a high on/off ratio of 711 and a fast rise time of 0.5ms. Notably, the polymer electrode and the bulk heterojunction demonstrated unique repairability and recyclability.

Energy harvesting and wireless communication by carbon fiber-reinforced polymer-enhanced piezoelectric nanocomposites

Piezoelectric Internet of Things (IoT) sensors with energy-harvesting capabilities, which can convert mechanical energy into electrical energy, promote battery-less systems. Such sensors can harness the vibration generated by spacecraft and other moving objects, eliminating the need for external power sources or battery replacements, thereby improving the autonomy and reliability of the system. This study investigates the features of a novel piezoelectric vibration energy harvester (PVEH) that comprises a carbon fiber-reinforced polymer (CFRP) electrode. The CFRP electrode provides outstanding electrical conductivity (7190 S/m) and enhances the mechanical characteristics of the energy collector, thereby ensuring a steady electrical energy yield during resonance. The piezoelectric composite consists of potassium sodium niobate (KNN) nanoparticles mixed with epoxy resin. Results show that when the KNN content is about 30 vol%, the piezoelectric properties of d33 and d31 are 15.21 pC/N and − 5.68 pC/N, respectively. Under an applied displacement of 0.05 mm, the CFRP-reinforced PVEH (C-PVEH) provides an impressive output energy volume density of 89.61 μW/cm3, which is capable of lighting LED bulbs with ease. Notably, this technology shows great application potential for powering wireless communication systems, indicating a remarkable advancement in the field of self-powered IoT sensors. This study provides valuable insights into the potential application of this groundbreaking technology.

High-Performance Poly(1-naphthylamine)/Mesoporous Carbon Cathode for Lithium-Ion Batteries with Ultralong Cycle Life of 45000 Cycles at -15°C.

Organic electrode materials for lithium-ion batteries have attracted significant attention in recent years. Polymer electrode materials, as compared to small-molecule electrode materials, have the advantage of poor solubility, which is beneficial for achieving high cycling stability. However, the severe entanglement of polymer chains often leads to difficulties in preparing nanostructured polymer electrodes, which is vital for achieving fast reaction kinetics and high utilization of active sites. This study demonstrates that these problems can be solved by the in situ electropolymerization of electrochemically active monomers in nanopores of ordered mesoporous carbon (CMK-3), combining the advantages of the nano-dispersion and nano-confinement effects of CMK-3 and the insolubility of the polymer materials. The as-prepared nanostructured poly(1-naphthylamine)/CMK-3 cathode exhibits a high active site utilization of 93.7%, ultrafast rate capability of 60Ag-1 (≈320C), and an ultralong cycle life of 10000 cycles at room temperature and 45000 cycles at -15°C. The study herein provides a facile and effective method that can simultaneously solve both the dissolution problem of small-molecule electrode materials and the inhomogeneous dispersion issue of polymer electrode materials.

Solid-contact polymeric membrane ion-selective electrodes using a covalent organic framework@reduced graphene oxide composite as ion-to-electron transducer.

A solid-contact ion-selective electrode (SC-ISE) based on a covalent organic framework@reduced graphene oxide (rGO) composite is proposed. The composite can be synthesized through the polycondensation of 1,3,5-triformylphloroglucinol (TFP) and 2,6-diaminoanthraquinone (DAAQ) on the rGO nanosheets, which shows high capacitance and good redox-active properties. By applying Cd2+-ISE as a model, the electrode exhibits a Nernstian slope of 29.7±0.4 mV/decade in the activity range of 1.0×10-7 - 7.9×10-4M and the limit of detection is 6.8×10-8M. Particularly, the electrode based on DAAQ-TFP@rGO exhibits a low potential drift of 1.2±0.2μV/h over 70h due to the large capacitance of 2.0mF. Moreover, the DAAQ-TFP@rGO-based Cd2+-ISE shows good reproducibility and the standard deviations of the standard potentials for single batch and batch-to-batch are 0.28 (n=4) and 0.30mV (n=4), respectively. The developed SC-Cd2+-ISE is not disturbed by light or gas and no aqueous layer occurs between the sensing membrane and DAAQ-TFP@rGO layer. The DAAQ-TFP@rGO composite is highly promising for construction of calibration-free SC-ISEs.

Ion-Selective Electrodes With Sensing Membranes Covalently Attached to Both the Inert Polymer Substrate and Conductive Carbon Contact.

The use of solid-contact ion-selective electrodes (ISEs) is of interest to many clinical, environmental, and industrial applications. However, upon extended exposure to samples and under thermal and mechanical stress, adhesion between these membranes and underlying substrates often weakens gradually. Eventually, this results in the formation of a water layer at the interface to the underlying electron conductor and in delamination of the membrane from the electrode body, both major limitations to long-term monitoring. To prevent these problems without increasing the complexity of design with a mechanical attachment, we use photo-induced graft polymerization to simultaneously attach ionophore-doped crosslinked poly(decyl methacrylate) sensing membranes covalently both to a high surface area carbon as ion-to-electron transducer and to inert polymeric electrode body materials (i.e., polypropylene and poly(ethylene-co-tetrafluoroethylene)). The sensors provide high reproducibility (standard deviation of E0 of 0.2 mV), long-term stability (potential drift 7 μV h-1 over 260 h), and resistance to sterilization in an autoclave (121 °C, 2.0 atm for 30 min). For this work, a covalently attached H+ selective ionophore was used to prepare pH sensors with advantages over conventional pH glass electrodes, but similar use of other ionophores makes this approach suitable to the fabrication of ISEs for a variety of analytes.

Ion‐Selective Electrodes With Sensing Membranes Covalently Attached to Both the Inert Polymer Substrate and Conductive Carbon Contact

AbstractThe use of solid‐contact ion‐selective electrodes (ISEs) is of interest to many clinical, environmental, and industrial applications. However, upon extended exposure to samples and under thermal and mechanical stress, adhesion between these membranes and underlying substrates often weakens gradually. Eventually, this results in the formation of a water layer at the interface to the underlying electron conductor and in delamination of the membrane from the electrode body, both major limitations to long‐term monitoring. To prevent these problems without increasing the complexity of design with a mechanical attachment, we use photo‐induced graft polymerization to simultaneously attach ionophore‐doped crosslinked poly(decyl methacrylate) sensing membranes covalently both to a high surface area carbon as ion‐to‐electron transducer and to inert polymeric electrode body materials (i.e., polypropylene and poly(ethylene‐co‐tetrafluoroethylene)). The sensors provide high reproducibility (standard deviation of E0 of 0.2 mV), long‐term stability (potential drift 7 μV h−1 over 260 h), and resistance to sterilization in an autoclave (121 °C, 2.0 atm for 30 min). For this work, a covalently attached H+ selective ionophore was used to prepare pH sensors with advantages over conventional pH glass electrodes, but similar use of other ionophores makes this approach suitable to the fabrication of ISEs for a variety of analytes.

High Density Body Surface Potential Mapping with Conducting Polymer-Eutectogel Electrode Arrays for ECG imaging.

Electrocardiography imaging (ECGi) is a non-invasive inverse reconstruction procedure which employs body surface potential maps (BSPM) obtained from surface electrode array measurements to improve the spatial resolution and interpretability of conventional electrocardiography (ECG) for the diagnosis of cardiac dysfunction. ECGi currently lacks precision, which has prevented its adoption in clinical setups. The introduction of high-density electrode arrays could increase ECGi reconstruction accuracy but is not attempted before due to manufacturing and processing limitations. Advances in multiple fields have now enabled the implementation of such arrays which poses questions on optimal array design parameters for ECGi. In this work, a novel conducting polymer electrode manufacturing process on flexible substrates is proposed to achieve high-density, mm-sized, conformable, long-term, and easily attachable electrode arrays for BSPM with parameters optimally selected for ECGi applications. Temporal, spectral, and correlation analysis are performed on a prototype array demonstrating the validity of the chosen parameters and the feasibility of high-density BSPM, paving the way for ECGi devices fit for clinical application.