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A poly(p-phenylene)-based multiblock polymer is developed with an oligomeric chain extender and cerium (CE-sPP-PPES + Ce3+) to realize better performance and durability in proton exchange membrane fuel cells. The membrane performance is evaluated in single cells at 80 °C and at 100% and 50% relative humidity (RH). The accelerated stability test is conducted 90 °C and 30% RH, during which linear sweep voltammetry and hydrogen permeation detection are monitored periodically. Results demonstrate that the proton conductivity of the pristine hydrocarbon membranes is superior to that of PFSA membranes, and the hydrogen crossover is significantly lower. In addition, a composite membrane containing cerium performs similarly to a pristine membrane, particularly at low RH levels. Adding cerium to CE-sPP-PPES + Ce3+ membranes improves their chemical durability significantly, with an open circuit voltage decay rate of only 89 μV/h for 1000 h. The hydrogen crossover is maintained across accelerated stability tests, as confirmed by hydrogen detection and crossover current density. The short-circuit resistance indicates that membrane thinning is less likely to occur. Collectively, these results demonstrate that a hydrocarbon membrane with cerium is a potential alternative for fuel cell applications.

Energy harvester-integrated wireless devices are attractive for generating semi-permanent power from wasted energy in industrial environments. The energy-harvesting wireless devices may have difficulty in their communication with access points due to insufficient power supply for beacon recognition during network initialization. In this manuscript, we propose a novel method of beacon recognition based on wake-up control to reduce instantaneous power consumption in the initialization procedure. The proposed method applies a moving window for the periodic wake-up of the wireless devices. For unsynchronized wireless devices, beacons are always located in the same positions within each beacon interval even though the starting offsets are unknown. Using these characteristics, the moving window checks the existence of the beacon associated withspecified resources in a beacon interval, checks again for neighboring resources at the next beacon interval, and so on. This method can reduce instantaneous power and generates a surplus of charging time. Thus, the proposed method alleviates the problems of power insufficiency in the network initialization. The feasibility of the proposed method is evaluated using computer simulations of power shortage in various energy-harvesting conditions.

Improper ferroelectricity and canted ferromagnetism in antiferromagnetically ordered hexagonal ferrites with A2-type spin configuration have been intensely studied due to their potential for room-temperature multiferroicity with strong magnetoelectric couplings. However, the subtle interplay between the magnetic structure and trimer structural distortion, which is a critical ingredient for ferroelectricity, has not been clearly verified in experiments due to the lack of control over trimer distortion. In this study, we report on Lu0.6In0.4FeO3, which exhibits weaker trimer distortion primarily related to the smaller tilting of the FeO5 bipyramids. The reduced vertical displacement of the equatorial oxygen of FeO5 located at the center of the trimer lowers the magnitude of the in-plane Dzyaloshinskii–Moriya vector component, resulting in the absence of canted ferromagnetism with the planar A1-type spin configuration, rather than the canted A2-type observed in other hexagonal ferrites. Our findings demonstrate that the degree of trimer distortion plays an important role in determining the spin configuration in related hexagonal systems. [ABSTRACT FROM AUTHOR]

In adapting to the demands of this modernized landscape, a conventional human-operated forklift within an industrial or warehouse setting falls short. However, the adoption of autonomous forklifts remains a distant prospect for many companies, primarily due to the formidable implementation and switching costs associated with artificial intelligence and complex control mechanisms. To bridge this gap, we present the development of a teleoperated forklift utilizing mecanum wheels for enhanced maneuverability. A key contribution of this work lies in the design of a novel synchronization method for the precise position control of the pallet carriers. This method surpasses the conventional independent and master–slave approaches, demonstrably achieving superior tracking and synchronization performance. Also, a model-based velocity control algorithm was designed for the mecanum wheels to facilitate the mobility of the system. The forklift was successfully able to carry a maximum load of 300 kg. For the comparison of the tracking and synchronization performance, the independent and master–slave methods were also applied to the system. The proposed method showed better performance compared to other structures. [ABSTRACT FROM AUTHOR]

A proton exchange membrane (PEM) is a crucial component for the effective and stable operation of energy conversion and storage devices, such as fuel cells, water electrolyzers, and redox flow batteries. However, perfluorinated sulfonic acid (PFSA) membranes—the most widely used PEM—have ultimate limitations of low proton selectivity to other active species because of their wide and randomly connected proton channels. Many attempts have been made to enhance the ion selectivity through morphology control, but it is still necessary to achieve significant improvement to overcome the permeability–selectivity trade-off. In this study, we demonstrate an ultrathin (∼30 nm) PFSA membrane with highly ordered hydrophilic domains. The well-controlled nanostructures are generated from the pre-aligned PFSA ionomers on the aqueous substrate, and further morphology development in the size and orientation of domains, and crystallinity, is finely adjusted via thermal annealing. Through this bottom-up morphology control, the ultrathin membrane has highly aligned ion channels with 55% crystallinity, resulting in about 800 times higher proton selectivity and 2 orders of magnitude lower areal resistance compared to 25 μm-thick PFSA membranes (Nafion 211). Furthermore, when the ultrathin membrane is applied to a vanadium redox flow battery (VRFB), the cell shows higher energy efficiency (∼76%) than a cell with a commercial Nafion membrane at the current density of 200 mA cm−2. [ABSTRACT FROM AUTHOR]

Parallel‐type organic electrochemical transistors (p‐OECTs) with aqueous electrolyte gate dielectrics have been widely studied for transducing biological signals into electrical signals. However, aqueous liquid electrolyte‐based p‐OECTs suffer from poor device stability, low transconductance (gm), and limited applications. In this study, a quasi‐solid‐state ion gel‐gated vertical‐type OECT (v‐OECT) and NOT logic gate are successfully demonstrated by combining both p‐type and n‐type v‐OECTs for the first time. Indacenodithiophene (IDT) polymers with alkyl (PIDTC16‐BT) and oligoethylene glycol (OEG) substituents (PIDTPEG‐BT) are studied as a channel material, and an ionic liquid in a crosslinked polymer matrix is adopted as a quasi‐solid electrolyte. Compared to aqueous devices, an enlarged electrochemical window and improved operational stability are observed. Notably, the v‐OECTs have a significantly larger channel area (50 × 50 µm2) and shorter channel length (≈30 nm), yielding a dramatically increased gm. As‐spun PIDTC16‐BT films exhibit a noticeably higher gm of 72.8 mS than that of previous p‐OECTs along with superior device stability, despite a low volumetric capacitance. In the case of v‐OECTs, face‐on intermolecular packing is required to increase the carrier transport in a vertical direction. Logic gates are successfully demonstrated using p‐ and n‐type v‐OECTs, suggesting the potential of OECT‐based next‐generation electronics. [ABSTRACT FROM AUTHOR]

A new donor–donor (D–D′)-type polymer (PIDTSCDTS) based on electron-rich indacenodithiophene (IDT) and cyclopentadithiophene (CDT) moieties is synthesized with extended π-conjugation and pronounced chain planarity through substitution with sp2-hybridized alkenyl side chains. Its thermoelectric (TE) properties are studied in detail depending on the doping methods: sequential doping (SqD), solution-mixed doping (MxD), and hybrid doping (HyD) with AuCl3 and FeCl3 as p-dopants. The carrier generation and transport depend strongly on the doping method. A higher conductivity (σ) of up to ∼500 S cm−1 is achieved using HyD (compared with other methods) owing to the significantly higher (bi)polaron generation (of up to ∼1021 cm−3) by doping both the amorphous and crystalline regions. Analyzing the relationship between the Seebeck coefficient (S) and the conductivity (σ) based on the Kang–Snyder model, metal-like carrier transport is observed for polymers obtained via SqD and HyD, which has been barely reported in organic TE polymers. The higher transport coefficient (σE0) in the HyD films reduces the S–σ trade-off relation, leading to a larger maximum power factor, PFmax, of ∼40 μW m−1 K−2 with simultaneously enhanced σ and S values compared with SqD films (16 μW m−1 K−2). To further optimize the TE properties, the degenerate doping and band-like carrier transport with maximizing the σE0 need to be carefully considered for the molecular design and doping process. [ABSTRACT FROM AUTHOR]

A new hydrocarbon-based (HC) composite membrane was developed using liquid crystal polymer (LCP)-nonwoven fabrics for application in proton exchange membrane water electrolysis (PEMWE). A copolymer of sulfonated poly(arylene ether sulfone) with a sulfonation degree of 50 mol% (SPAES50) was utilized as an ionomer for the HC membranes and impregnated into the LCP-nonwoven fabrics without any surface treatment of the LCP. The physical interlocking structure between the SPAES50 and LCP-nonwoven fabrics was investigated, validating the outstanding mechanical properties and dimensional stability of the composite membrane in comparison to the pristine membrane. In addition, the through-plane proton conductivity of the composite membrane at 80 °C was only 15% lower than that of the pristine membrane because of the defect-free impregnation state, minimizing the decrease in the proton conductivity caused by the non-proton conductive LCP. During the electrochemical evaluation, the superior cell performance of the composite membrane was evident, with a current density of 5.41 A/cm2 at 1.9 V, compared to 4.65 A/cm2 for the pristine membrane, which can be attributed to the smaller membrane resistance of the composite membrane. From the results of the degradation rates, the prepared composite membrane also showed enhanced cell efficiency and durability during the PEMWE operations. [ABSTRACT FROM AUTHOR]

Glassy hydrocarbon-based membranes are being researched as a replacement for perfluorosulfonic acid (PFSA) membranes in proton exchange membrane water electrolysis (PEMWE). Here, naphthalene containing Poly(arylene Ether Ketone) was introduced into the Poly(p-phenylene)-based multi-block copolymers through Ni(0)-catalyzed coupling reaction to enhance π-π interactions of the naphthalene units. It is discovered that there is an optimum input ratio of the hydrophilic monomer and NBP oligomer for the multi-block copolymers with high ion exchange capacity (IEC) and polymerization yield. With the optimum input ratio, the naphthalene containing copolymer exhibits good hydrogen gas barrier property, chemical stability, and mechanical toughness, even with its high IEC value over 2.4 meq g−1. The membrane shows 3.6 times higher proton selectivity to hydrogen gas than Nafion 212. The PEMWE single cells using the membrane performed better (5.5 A cm−2) than Nafion 212 (4.75 A cm−2) at 1.9 V and 80 °C. These findings suggest that naphthalene containing copolymer membranes are a promising replacement for PFSA membranes in PEMWE. [ABSTRACT FROM AUTHOR]

Thermoelectric (TE) performance of a specific semicrystalline polymer is studied experimentally only in a limited range of doping levels with molecular doping methods. The doping level is finely controlled via in situ electrochemical doping in a wide range of carrier concentrations with an electrolyte ([PMIM]+[TFSI]−)‐gated organic electrochemical transistor system. Then, the charge generation/transport and TE properties of four p‐type semicrystalline polymers are analyzed and their dynamic changes of crystalline morphologies and local density of states (DOS) during electrochemical doping are compared. These polymers are synthesized based on poly[(2,5‐bis(2‐alkyloxy)phenylene)‐alt‐(5,6‐difluoro‐4,7‐di(thiophene‐2‐yl)benzo[c][1,2,5]thiadiazole)] by varying side chains: With oligoethylene glycol (OEG) substituents, facile p‐doping is achieved because of easy penetration of TFSI− ions into the polymer matrix. However, the charge transport is hindered with longer OEG chains length because of the enhanced insulation. Therefore, with the shortest OEG substituents the electrical conductivity (30.1 S cm−1) and power factor (2.88 µW m−1 K−2) are optimized. It is observed that all polymers exhibit p‐ to n‐type transition in Seebeck coefficients in heavily doped states, which can be achieved by electrochemical doping. These TE behaviors are interpreted based on the relation between the localized DOS band structure and molecular packing structure during electrochemical doping. [ABSTRACT FROM AUTHOR]

This research presents a novel methodology for measuring the complex permittivity of a material under test (MUT) in a millimeter-wave (mmWave) band by using two rectangular waveguide adapters. Contrary to the conventional Nicolson-Ross-Weir (NRW) method, the proposed complex permittivity measurement method does not require a material fabrication process for exact MUT insertion into a waveguide. In our complex permittivity measurement, simple commercial waveguide adapters are employed instead of large flange structures. The proposed complex permittivity measurement of a non-destructive MUT is achieved by combining the NRW method, the Gaussian weighting moving average filtering technique, a full-wave electromagnetic analysis, and an optimization technique. Furthermore, the proposed methodology is validated by fabricating a Teflon-based MUT and by measuring the complex permittivity of the MUT in the Ka band (26.5-40 GHz). The results indicate that the proposed methodology exhibits good agreement with the data sheet. [ABSTRACT FROM AUTHOR]

Three p‐type thermoelectric (TE) polymers based on the indacenodithiophene moiety substituted with bis(alkylsulfanyl)methylene side‐chains (IDTS) are synthesized. The TE characteristics of IDTS‐based donor–donor' (D–D′) type PIDTSDTTT and donor–acceptor (D–A) type polymers, PIDTSBT and PIDTS2FBT are investigated. Remarkably higher electrical conductivity (σ = ≈1000 S cm−1) and power factor (PF = ≈120 μW m−1 K−2) by doping with AuCl3 are measured for PIDTSDTTT compared to D–A type polymers. The higher σ of PIDTSDTTT originates from its higher carrier concentration compared to those of PIDTSBT and PIDTS2FBT. Moreover, the facile polaron‐to‐bipolaron transition is measured, and the charge carriers are calculated to be more stable with extended delocalization in PIDTSDTTT compared to D–A polymers. The significantly higher doping stability in PIDTSDTTT can be explained in terms of the higher conduction band of bipolarons than the valence band of O2 and H2O, which blocks the facile reduction of bipolarons in air. The energetic structures of doped polaron and bipolaron states, as well as pristine TE polymers, must be carefully considered to realize efficient and stable p‐type thermoelectric polymers, where a D–D′ type structure with further enhanced carrier mobility can be considered as a potential molecular framework. [ABSTRACT FROM AUTHOR]

Recent success in experimental and theoretical works on metal thiophosphates (MTPs) paved the way to add multiple functionalities of complex oxides, such as ferroelectricity, in 2D materials. To realize multiferroicity and magnetoelectric coupling on layered van der Waals materials, incorporating magnetic ions in the ferroelectric framework is desirable. Unfortunately, replacing the metal ion with a magnetic one in MTPs results in antiferroelectricity in which spontaneous macroscopic polarization is absent. Herein, the emergence of a tunable local ferroelectric state in antiferroelectric CuCrP2S6 possessing magnetic Cr3+ ion is reported. The spontaneous macroscopic polarization is observed, which is switchable by an external poling field through controlling a defect‐dipole polarization in the quasi‐antipolar state. The observations suggest that the formation of defect dipoles, which is facilitated by an order‐disorder‐type structural transition, is likely related to a metastable Cu site within the van der Waals gap and therefore is a smoking gun of the existence of a uniaxial quadruple potential well. The interaction between the defect‐dipole polarization and dipoles in the antipolar matrix may lead to the emerging local ferroelectricity in antiferroelectric CuCrP2S6. The findings suggest a possibility of utilizing the local ferroelectricity of multiferroic MTPs for novel 2D applications. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease (FMD) is an economically important and highly infectious viral disease, predominantly controlled by vaccination. The removal of non-structural proteins (NSPs) is very important in the process of FMD vaccine production, because vaccinated and naturally infected animals can be distinguished by the presence of NSP antibodies in the FMD serological surveillance. A previous study reported that 3AB protein, a representative of NSPs, was removed by chloroform treatment. Therefore, in this study, the causes of 3AB removal and factors affecting the effect of chloroform were investigated. As a result, the effectiveness of chloroform differed depending on the virus production medium and was eliminated by detergents. In addition, it was found that 3AB protein removal by chloroform is due to the transmembrane domain of the N-terminal region (59–76 amino acid domain). Further, industrial applicability was verified by applying the chloroform treatment process to scale-up FMD vaccine antigen production. A novel downstream process using ultrafiltration instead of polyethylene glycol precipitation for high-purity FMD vaccine antigen production was established. This result will contribute toward simplifying the conventional process of manufacturing FMD vaccine antigens and ultimately reducing the time and cost of vaccine production. [ABSTRACT FROM AUTHOR]

Herein, we report a series of oligomeric chain extender-derived AEMs (QPP-b-PSK-w-TMA) with increased molecular weights. The QPP-b-PSK-w-TMA membranes showed excellent polymer main-chain stability as well as outstanding hydroxide conductivity, 129 mS cm1 at 80 -C, which is 1.6 times higher than that of FAA-3, moreover, the QPP-b-PSK-w-TMA also exhibited remarkable thermally stable rheological properties originating from the main chain structure. Using the QPP-b-PSK-3.5-TMA membrane, we demonstrated that a high performance low platinum group metal (PGM)-loaded AEMFC showed a high specific power of 4.9 W mgPGM 1, which is the highest value among those reported for the state-of-theart AEMFCs with PGM-based electrodes. In addition, an AEMWE with the QPP-b-PSK-3.5-TMA membrane showed a high performance of 4.0 A cm2 at 1.9 V under 90 -C and durable performance with a low degradation rate of 1.2 mV h1 for 100 h despite the use of the NiFe catalyst under 80 -C. [ABSTRACT FROM AUTHOR]

Herein, we developed polyacrylonitrile (PAN)-based nanoporous composite membranes incorporating aluminum diethylphosphinate (ADEP) for use as a heat-resistant and flame-retardant separator in high-performance and safe lithium-ion batteries (LIBs). ADEP is phosphorus-rich, thermally stable, and flame retardant, and it can effectively suppress the combustibility of PAN nanofibers. Nanofibrous membranes were obtained by electrospinning, and the content of ADEP varied from 0 to 20 wt%. From the vertical burning test, it was demonstrated that the flame retardancy of the composite membranes was enhanced when more than 5 wt% of ADEP was added to PAN, potentially increasing the safety level of LIBs. Moreover, the composite membrane showed higher ionic conductivity and electrolyte uptake (0.83 mS/cm and 137%) compared to those of commercial polypropylene (PP) membranes (Celgard 2400: 0.65 mS/cm and 63%), resulting from interconnected pores and the polar chemical composition in the composite membranes. In terms of battery performance, the composite membrane showed highly stable electrochemical and heat-resistant properties, including superior discharge capacity when compared to Celgard 2400, indicating that the PAN/ADEP composite membrane has the potential to be used as a heat-resistant and flame-retardant separator for safe and high-power LIBs. [ABSTRACT FROM AUTHOR]

Recently, organic thermoelectric (TE) materials have been intensively studied because of their great potential for application in flexible/wearable TE generators for power generation at low temperatures. However, reports on the development of efficient n-type TE materials and their TE properties are much less in number than those on p-type TE materials. Significant efforts have been recently directed toward the development of n-type organic TE materials, n-dopants, and doping methods. Outstanding advances have been achieved in this field, and various n-type structures with TE performance comparable to that of p-type structures have been developed. The molecular library of novel n-type building blocks and the resulting n-type small molecular and polymeric TE materials, as well as n-dopants, has been significantly extended. In this regard, we believe that it would be of great significance to review the recent advances in the field of n-type organic TE materials and highlight important scientific breakthroughs. In this review, the recent developments in the fields of n-type organic TE materials and n-type dopants, as well as innovative doping techniques are discussed. Finally, the current challenges and future prospects are discussed to provide guidelines for the development of high-performance n-type TE materials. [ABSTRACT FROM AUTHOR]