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A ledge feature in the capacitance–voltage (CV) profiles of Ga2O3 MOS (metal–oxide–semiconductor) capacitors is investigated using UV-assisted CV measurements. A model is presented whereby the capacitance ledge is associated with carrier trapping in deep-level states at the Al2O3/Ga2O3 interface. Following UV assisted emptying of interface traps at a constant bias, a voltage ramp toward flatband results in a CV ledge when the trap recombination current becomes equal to the quasi-static sweep charging current. The ledge continues until all the traps below the corresponding pinned surface potential have been filled. Varying the UV energy varies the ledge voltage range and allows a density of states to be determined as a function of energy. A broad interface state peak with maximum density ∼8 × 1012 cm−2 eV−1 for deep trap energies lying between 2.4 and 4.1 eV below the conduction band (CB) edge is extracted. Using the conductance method, the interface trap density is also found to rise toward the CB edge in the range 0.25–0.45 eV below the CB edge, reaching a maximum density of ∼1 × 1012 cm−2 eV−1. Combining these two techniques, an interface trap distribution is estimated for almost the entirety of the bandgap of Ga2O3. This novel technique probes deep interface states where standard methods fail to quantify interface states reliably. [ABSTRACT FROM AUTHOR]

At the turn of the millennium, developments on metasurfaces lead to a significant step forward in the design of radar absorbing structures, especially at lower frequencies, thanks to a reduced thickness. Still, as with other passive impedance matching systems, they remain constrained in their bandwidth-to-thickness ratio. Fortunately, the recent integration of active electronic components onto metasurfaces has multiplied their functionalities, unlocking new ways to overcome these limitations. For instance, using varactor diodes, which act as variable capacitors, an absorbing metasurface can be rendered tunable to cover a frequency range wider than would any passive system of similar thickness. This is a valuable feature when facing modern frequency-hopping radars. However, the bias-dependent resistance introduced by the varactor diodes can compromise the impedance matching throughout the tunable frequency range. This work, therefore, focuses on the design and measurement of a tunable radar absorbing metasurface using varactor diodes, highlighting the necessity for a joint tuning of capacitance and resistance to grant near-perfect absorption over a wide frequency range. [ABSTRACT FROM AUTHOR]

The study of interface states and bulk traps and their connection to device instability is highly demanded to achieve reliable β-Ga2O3 metal-oxide-semiconductor (MOS) devices. However, a comprehensive analysis of the capture/emission behavior of interface states and bulk traps can be challenging due to widespread time constant distribution. In this study, using capacitance transient measurement tools, trap states of the ZrO2/β-Ga2O3 MOS gate stack were explicitly investigated, particularly its bias- and temperature-dependent relaxation kinetics. As forward bias is enlarged, it is observed that the interface state density (Dit) increases by 12.6%. Two bulk traps with discrete levels identified as 0.43 eV (E1) and 0.74 eV (E2) below the conduction band minimum were extracted by deep-level transient spectroscopy. It is further revealed that the emission processes of E1 and E2 are thermally enhanced, while the capture processes remain insensitive to temperature. The electric-field dependence of E1 indicates that the dominant mechanism follows the rule of Poole–Frenkel emission. The capacitance–voltage (C–V) hysteresis deteriorated at a higher forward bias due to the higher trap density and increased population of trapped charges. These findings provide an important framework for future device optimization to improve the reliability and performance of β-Ga2O3 MOS devices. [ABSTRACT FROM AUTHOR]

Increasingly, society requires high power, high energy storage devices for applications ranging from electric vehicles to buffers on the electric grid. Supercapacitors are a promising contribution to meeting these demands, though there still remain unsolved practical problems. Molecular dynamics simulations can shed light on the relevant molecular level processes in electric double layer capacitors, but these simulations are computationally very demanding. Our focus here is on the algorithmic complexity of the constant potential method (CPM), which uses dedicated electrostatics solvers to maintain a fixed potential difference between two conducting electrodes. We show how any standard electrostatics solver—capable of calculating the energies and forces on all atoms—can be used to implement CPM with a minimum of coding. As an example, we compare our generalized implementation of CPM, based on invocations of the particle–particle–particle–mesh routine of the Large-scale Atomic/Molecular Massively Parallel Simulator, with a traditional implementation based on a dedicated re-implementation of Ewald summation. Both methods yield comparable results on four test systems, with the former achieving a substantial gain in speed and improved scalability. The step from dedicated electrostatic solvers to generic routines is made possible by noting that CPM's traditional narrow Gaussian point-spread of atomic charges on the electrodes effectively endows point-like atoms with chemical hardness, i.e., an intra-atomic energy quadratic in the charge. [ABSTRACT FROM AUTHOR]

Active thermography using pulsed heating is a fast and reliable method for detecting flaws in composite and metallic materials. This paper analyzes the temperature decay that occurs immediately after flash heating the front surface of stainless steel specimens as a function of time, based on a novel application of the equivalent circuit approach (ECA). The temperature decay from the front surface is equated to the discharge of a capacitor. The ECA is based on the charging (temperature rise due to flash heating) of a capacitor, followed by its discharge (temperature decay) through a series of resistors (which depends on the conductivity of the material) and capacitance (which depends on the thermal capacitance of the layers) through which the heat is dissipated. The proposed approach analyzes the sequences of temperature data obtained at each pixel location during cooling from a step wedge and a specimen with multiple flat-bottom holes. Time constant maps derived from the analysis are used to ascertain the thickness of the step wedge, detect the flaws, and evaluate the remnant thickness of the flaws. A correlation has been established between the thickness and the time constants. The above approach has been used to estimate the diameter of the flat-bottom holes. [ABSTRACT FROM AUTHOR]

Electrochemical Double Layer Capacitors (EDLCs) with ionic liquid electrolytes outperform conventional ones using aqueous and organic electrolytes in energy density and safety. However, understanding the electrochemical behaviors of ionic liquid electrolytes under compressive/tensile strain is essential for the design of flexible EDLCs as well as normal EDLCs, which are subject to external forces during assembly. Despite many experimental studies, the compression/stretching effects on the performance of ionic liquid EDLCs remain inconclusive and controversial. In addition, there is hardly any evidence of prior theoretical work done in this area, which makes the literature on this topic scarce. Herein, for the first time, we developed an atomistic model to study the processes underlying the electrochemical behaviors of ionic liquids in an EDLC under strain. Constant potential non-equilibrium molecular dynamics simulations are conducted for EMIM BF4 placed between two graphene walls as electrodes. Compared to zero strain, low compression of the EDLC resulted in compromised performance as the electrode charge density dropped by 29%, and the performance reduction deteriorated significantly with a further increase in compression. In contrast, stretching is found to enhance the performance by increasing the charge storage in the electrodes by 7%. The performance changes with compression and stretching are due to changes in the double-layer structure. In addition, an increase in the value of the applied potential during the application of strain leads to capacity retention with compression revealed by the newly performed simulations. [ABSTRACT FROM AUTHOR]

In recent years, neural networks have achieved phenomenal success across a wide range of applications. They have also proven useful for solving differential equations. The focus of this work is on the Poisson–Boltzmann equation (PBE) that governs the electrostatics of a metal–oxide–semiconductor capacitor. We were motivated by the question of whether a neural network can effectively learn the solution of PBE using the methodology pioneered by Lagaris et al. [IEEE Trans. Neural Netw. 9 (1998)]. In this method, a neural network is used to generate a set of trial solutions that adhere to the boundary conditions, which are then optimized using the governing equation. However, the challenge with this method is the lack of a generic procedure for creating trial solutions for intricate boundary conditions. We introduce a novel method for generating trial solutions that adhere to the Robin and Dirichlet boundary conditions associated with the PBE. Remarkably, by optimizing the network parameters, we can learn an optimal trial solution that accurately captures essential physical insights, such as the depletion width, the threshold voltage, and the inversion charge. Furthermore, we show that our functional solution can extend beyond the sampling domain. [ABSTRACT FROM AUTHOR]

Electrode–electrolyte interfacial properties characterize the functioning of electrochemical devices, and reactive molecular dynamics simulations, using reactive force fields (ReaxFF) and charge equilibration (QEq) techniques, are classical atomistic methods for investigating the processes that govern the device properties. However, the numerical implementation of ReaxFF and QEq treats Coulomb interaction with a short-distance cutoff for computational speed, thereby limiting interactions among atoms to a domain containing only their neighbor lists. Excluding long-distance Coulomb interactions makes the description of electrostatics in large-scale systems intractable. We apply Ewald sum in the extension of ReaxFF to include long-range Coulomb (LRC) interactions and investigate the effect of the inclusion on the electrostatic and capacitive properties of graphene–water interfaces at different applied potentials in comparison with the original ReaxFF. The study shows that with the inclusion of long-range Coulomb, the capacitance amounts to 4.9 ± 0.2 μF cm−2 compared with 4.4 ± 0.2 μF cm−2 predicted by the original ReaxFF [with short-range Coulomb (SRC)]; thus, indicating that SRC underestimates the capacitance of water between graphene walls by 12% when compared with the 5.0 μF cm−2 predicted with the extended simple point charge (SPC/E) water model. Thus, the results indicate that LRC ReaxFF/QEq have the ability and advantage to model electrochemical processes at a more realistic Coulomb interaction description and foster the processing of the details about the operation of electrochemical devices than the SRC. [ABSTRACT FROM AUTHOR]

The relationship between the electrical properties and the carrier trap properties of the SiO2/GaN metal–oxide–semiconductor (MOS) capacitors was investigated using electrical measurements and deep level transient spectroscopy (DLTS). The capacitance–voltage (C–V) measurement showed that the frequency dispersion of the C–V curves became smaller after an 800 °C annealing in O2 ambient. DLTS revealed that before the annealing, the interface trap states, in a broad energy range above the midgap of GaN, were detected with the higher interface state density at around 0.3 and 0.9 eV below the conduction band minimum (EC) of GaN. Moreover, the oxide trap states were formed at around 0.1 eV below the EC of GaN, plausibly indicating a slow electron trap with a tunneling process. Although both trap states affect the electrical reliability and insulating property of the SiO2/GaN MOS capacitors, they were found to drastically decrease after the annealing, leading to the improvement of the electrical properties. [ABSTRACT FROM AUTHOR]

We present a method for simulating any non-interacting and time-periodic tight-binding Hamiltonian in Fourier space using electric circuits made of inductors and capacitors. We first map the time-periodic Hamiltonian to a Floquet Hamiltonian, which converts the time dimension into a Floquet dimension. In electric circuits, this Floquet dimension is simulated as an extraspatial dimension without any time dependency in the electrical elements. The number of replicas needed in the Floquet Hamiltonian depends on the frequency and strength of the drive. We also demonstrate that we can detect the topological edge states (including the anomalous edge states in the dynamical gap) in an electric circuit by measuring the two-point impedance between the nodes. Our method paves a simple and promising way to explore and control Floquet topological phases in electric circuits. [ABSTRACT FROM AUTHOR]

Within the framework of the classical, mean-field Poisson–Boltzmann (PB) theory, we carry out direct numerical simulations to determine the differential capacitance of a closed nanochannel of a circular cross section, embedded in a polymeric host with charged walls and sealed at both ends by metal electrodes under an external potential bias. Our approach employs the modified PB equation, which accounts for the finite size of ions and the dependency of the electrolyte's relative permittivity on the local electric field. In view of the absence of reservoirs, the modified PB equation becomes subject to global algebraic constraints, without prior knowledge of a bulk electrolyte concentration. Equilibrium ion distributions and differential capacitance curves are investigated as functions of electrolyte properties and the surface charge density modulation. This modulation leads to asymmetric differential capacitance curves that can be tuned. More generally, our approach provides a transparent numerical framework for accurately simulating confined nanofluidic systems with new physical properties that may be exploited in novel iontronic circuit elements. [ABSTRACT FROM AUTHOR]

[Display omitted] Three-dimensional interconnected nickel–cobalt layered double hydroxides (NiCo-LDHs) were prepared on nickel foam by ion exchange using a cobalt-based metal–organic framework (Co-MOF) as a template at different temperatures. The effects of the Co-MOF preparation temperature on the growth, mass, morphology, and electrochemical properties of the Co-MOF and derived NiCo-LDH samples were studied. The synthesis temperature from 30 to 50 °C gradually increased the mass of the active material and the thickness of the Co-MOF sheets grown on the nickel foam. The higher the temperature is, the larger the proportion of Co3+. β-Cobalt hydroxide (β-Co(OH) 2) sheets were generated above 60 °C. The morphology and mass loading pattern of the derived flocculent layer clusters of NiCo-LDH were inherited from metal-organic frameworks (MOFs). The areal capacitance of NiCo-LDH shows an inverted U-shaped curve trend with increasing temperature. The electrode material synthesized at 50 °C had a tremendous specific capacitance of 7631 mF·cm−2 at a current density of 2 mA·cm−2. The asymmetric supercapacitor assembled with the sample and active carbon (AC) achieved an energy density of 55.0 Wh·kg−1 at a power density of 800.0 W·kg−1, demonstrating the great potential of the NiCo-LDH material for energy storage. This work presents a new strategy for designing and fabricating advanced green supercapacitor materials with large power and energy densities. [ABSTRACT FROM AUTHOR]

Benefitting from the synergetic effects of heterostructured sulfide as the charge transfer accelerator and N -doped carbon matrix as an armor, the bimetallic FeS 2 /MoS 2 heterostructure confined in nitrogen-doped carbon (FMS@NC) delivers a comprehensive K-ions storage ability. Moreover, the as-built K-ion capacitor based on FMS@NC anode and activated carbon cathode achieves a high energy/power density as well as ultra-long cycling stability. [Display omitted] The means of structural hybridization such as heterojunction construction and carbon-coating engineering for facilitating charge transfer and electron transport are considered viable strategies to address the challenges associated with the low rate capability and poor cycling stability of sulfide-based anodes in potassium-ion batteries (PIBs). Motivated by these concepts, we have successfully prepared a hydrangea-like bimetallic sulfide heterostructure encapsulated in nitrogen-doped carbon (FMS@NC) using a simple solvothermal method, followed by poly-dopamine wrapping and a one-step sulfidation/carbonization process. When served as an anode for PIBs, this FMS@NC demonstrates a high specific capacity (585 mAh g−1 at 0.05 A/g) and long cycling stability. Synergetic effects of mitigated volume expansions and enhanced conductivity that are responsbile for such high performance have been verified to originate from the heterostructured sulfides and the N -doped carbon matrix. Meanwhile, comprehensive characterization reveals existence of an intercalation-conversion hybrid K-ion storage mechanism in this material. Impressively, a K-ion capacitor with the FMS@NC anode and a commercial activated carbon cathode exhibits a superior energy density of up to 192 Wh kg−1, a high power density, and outstanding cycling stability. This study provides constructive guidance for designing high-performance and durable potassium-ion storage anodes for next-generation energy storage devices. [ABSTRACT FROM AUTHOR]

A high performance lamellar structured Fe-doped MnS/graphene anode has been developed for sodium-ion storage. Due to the synergistic positive effect of graphene confinement, strong Mn S C bonding and Fe-doping, the composite exhibits excellent rate performance and long-term stability. A prototype sodium-ion capacitor fabricated with Fe-MnS/PG anode and nitrogen-doped carbon cathode can deliver both high energy and high power densities. [Display omitted] Manganese sulfide (MnS) is a promising converion-type anode for sodium storage, owing to the virtues of high theoretical capacity, coupled with it crustal abundance and cost-effectiveness. Nevertheless, MnS suffers from inadequate electronic conductivity, sluggish Na+ reaction kinetics and considerable volume variation during discharge/charge process, thereby impeding its rate capability and capacity retention. Herein, a novel lamellar heterostructured composite of Fe-doped MnS nanoparticles/positively charged reduced graphene oxide (Fe-MnS/PG) was synthesized to overcome these issues. The Fe-doping can accelerate the ion/electron transfer, endowing fast electrochemical kinetics of MnS. Meanwhile, the graphene space confinement with strong Mn S C bond interactions can facilite the interfacial electron transfer, hamper volume expansion and aggregation of MnS nanoparticles, stabilizing the structural integrity, thus improving the Na+ storage reversibility and cyclic stability. Combining the synergistic effect of Fe-doping and space confinement with strong Mn S C bond interactions, the as-produced Fe-MnS/PG anode presents a remarkable capacity of 567 mAh/g at 0.1 A/g and outstanding rate performance (192 mAh/g at 10 A/g). Meanwhile, the as-assembled sodium-ion capacitor (SIC) can yield a high energy density of 119 Wh kg−1 and a maximum power density of 17500 W kg−1, with capacity retention of 77 % at 1 A/g after 5000 cycles. This work offers a promising strategy to develop MnS-based practical SICs with high energy and long lifespan, and paves the way for fabricating advanced anode materials. [ABSTRACT FROM AUTHOR]

[Display omitted] The imbalances of storage capacity and reaction kinetics between carbonaceous cathodes and zinc (Zn) anodes restrict the widespread application of Zn-ion hybrid capacitor (ZIHC). Structure optimization is a promising strategy for carbon materials to achieve sufficient Zn2+ storage sites and satisfied ion–electron kinetics. Herein, porous graphitic carbon nanosheets (PGCN) were simply synthesized using a K 3 [Fe(C 2 O 4) 3 ]- and urea-assisted foaming strategy with polyvinylpyrrolidone as carbon precursor, followed by activation and graphitization. Sufficient pores with well-matched pore sizes (0.80–1.94 nm) distributed across the carbon nanosheets can effectively shorten mass-transfer distance, promoting accessibility to active sites. A partially graphitic carbon structure with high graphitization degree can accelerate electron transfer. Furthermore, high nitrogen doping (7.2 at.%) provides additional Zn2+ storage sites to increase storage capacity. Consequently, a PGCN-based ZIHC has an exceptional specific capacity of 181 mAh g−1 at 0.5 A g−1, superb energy density of 145 Wh kg−1, and excellent cycling ability without capacity decay over 10,000 cycles. In addition, the flexible solid-state device assembled with PGCN exhibits excellent electrochemical performances even when bent at various angles. This study proposes a straightforward and economical strategy to construct porous graphitic carbon nanosheets with enhanced storage capacity and fast reaction kinetics for the high performance of ZIHC. [ABSTRACT FROM AUTHOR]

CHB converters have been intensively considered for various applications. However, a reliability issue has emerged due to the higher number of power devices, particularly power semiconductor devices and capacitors, which have been identified as major sources of failure. Although continuous efforts have been made to enhance the reliability of power semiconductors through methods such as active thermal control, there is a noticeable absence of discussion regarding the reliability of capacitors. This is significant since capacitors are the components most prone to failure in power converters. In this study, the root mean square (RMS) current of the DC-link capacitor in a CHB converter is derived when applying thermally compensated discontinuous modulation for power semiconductors. To validate the obtained findings, the derived equations are experimentally tested using a proof-of-concept setup. [ABSTRACT FROM AUTHOR]

Modular multilevel converter-based solid-state transformers (MMC-SST) usually use the input series output parallel structure or the dual active bridge (DAB) structure. These two structures suffer from low power supply reliability and high economic costs, respectively. Therefore, based on hybrid frequency modulation, this paper proposes an arm integrated double capacitor submodule (AIDCSM)-type MMC-SST topology. This topology effectively reduces the number of switching devices by integrating the submodule arms, while enabling the topology to possess DC short-circuit fault ride-through capability. When compared to the DAB-type MMC-SST with half-bridge submodules, the proposed AIDCSM-type MMC-SST saves 2/5 switching devices and 1/2 high-frequency transformers, and enables uninterrupted operation under DC short-circuit faults. At the same time, the control strategy of the proposed AIDCSM-type MMC-SST is thoroughly investigated under both normal operating and DC short-circuit conditions. Simulation and experimental results demonstrate the correctness and effectiveness of the proposed topology and control method. [ABSTRACT FROM AUTHOR]

Modular multilevel converters (MMC) have the characteristics of high modularity, good availability and high-power quality. Thus, they are widely used in medium and high-power applications. To meet large capacity application requirements, a large number of capacitors is applied in parallel and series. However, capacitors are one of the most vulnerable components in MMCs. To identify abnormal capacitors, a condition monitoring method for capacitors is proposed in this paper using the cumulative sum detection of the sliding window algorithm. First, the bilateral cumulative sum algorithm of the sliding window is proposed to extract the switch-on time and switch-off time of the submodules (SMs). Second, the capacitance is calculated using the monitored capacitor voltage and arm current during the switch-on status. Finally, the accuracy and effectiveness of the proposed method are verified by an MMC system operating condition simulated experiment platform. The proposed condition monitoring method simplifies the calculation of capacitance with a high accuracy by removing the requirement of measuring the switching signal. In addition, it does not have an adverse influence on the normal operation of MMC systems. [ABSTRACT FROM AUTHOR]

Summary: In this communication, two new positive lossy series inductor simulator circuits using single current differencing buffered amplifier (CDBA), one capacitor, and three resistors are presented. In both the proposed circuits, the inductance value is independently controllable through a grounded resistor, which may be implemented using a voltage‐controlled resistor (VCR), facilitating electronic tuning. Moreover, one of the circuits presented utilizes the intrinsic resistance (internal resistance available at input ports p and n) of the CDBA, thereby enabling electronic control and establishing the inductor simulator as canonical. Both the circuits are analyzed for non‐ideal behavior by taking into account the parasitic elements of CDBA and compared with their ideal counterparts. To demonstrate the efficacy of the proposed series RL simulator circuits, SPICE simulations are performed using CMOS CDBA, and the performance of the proposed circuits is evaluated by designing a lead compensator. The simulation and experimental results of the proposed circuits, along with the application examples employing CDBA realized with the off‐the‐shelf available IC AD844, have also been corroborated. [ABSTRACT FROM AUTHOR]

Summary: The present study is devoted to articulating a modified folded‐cascode circuit, to make folded‐cascode structures an attractive configuration as a transimpedance amplifier (TIA) for being employed in Giga‐bit per second optical communication receiver systems. Giga‐bps communication receivers are highly necessitating circuits to isolate the input parasitic capacitance of the photodiode. The present modification makes folded cascodes comparable to the famous regulated cascode (RGC) structures by isolating this parasitic capacitor almost by the same quantity. The system is shown to be capable of operating at 2.5 Gbps up to 8 Gbps data rate with a fixed bandwidth. The paper analyzes and evaluates the designed circuit mathematically, and the obtained simulated results from Cadence using TSMC 65 nm CMOS validate the suitability of the modified circuit as a TIA. [ABSTRACT FROM AUTHOR]

Summary: Multilevel inverters (MLIs) have recently drawn the huge attention of industry and academia since they are becoming a viable technology for a variety of applications. However, the risk of failure of the converter increases with the increasing number of component count for applications involving heavy duty and continuous operation. In this context, an asymmetrical source configured FT‐MLI (fault tolerant‐MLI) topology is investigated and developed with less number of device count and having the ability to withstand both OC (open‐circuit) and SC (short‐circuit) switch faults on single and multiple switches. The proposed architecture maintains the same output voltage levels and power in both pre‐ and post‐fault operations. In addition, a switching method is developed to reduce the capacitors' size by minimizing the voltage ripple. Furthermore, without the need for an external circuit, the voltage across the capacitors remains balanced in both pre‐ and post‐fault operations. The simulation and experimental results are provided to demonstrate the effectiveness of the proposed asymmetrical FT‐MLI topology. Finally, a comparison of the proposed topology with the existing MLI topologies is shown to emphasize the benefits of the proposed system. [ABSTRACT FROM AUTHOR]

A newly designed third-order mixed-mode orthogonally tuned quadrature oscillator, generating sinusoidal voltage and current waveforms, is introduced in this paper. The reported circuit is realized using two dual-X current conveyor transconductance amplifiers (DXCCTAs), two active MOS-based grounded resistors and three grounded capacitors. MOS-C realization of the proposed oscillator with all grounded capacitors is the best choice for modern integration. In this study, the ideal and non-ideal analyses and frequency stability aspect of the circuit are elucidated. The proposed third-order oscillator circuit has the advantages of orthogonally controllable frequency of oscillation & condition of oscillation, very good operating frequency (34.25 MHz) and low total harmonic distortion (within 1.8%). The theoretical analyses have been validated by both pre-layout and post-layout simulations using general process design kit 0.18 μ m technology and the results have been compared with relevant state-of-the-art works. Layout of the used active block, DXCCTA, is developed with Cadence Virtuoso that measures an area of 38 μ m × 2 1 μ m. [ABSTRACT FROM AUTHOR]

In this paper, a new structure for a 1-bit full adder is proposed based on dynamic logic methodology, which utilises pass transistors. The clocking operation falls into two phases. The clocking operation consists of a pre-discharged cycle, during which pseudo capacitors are reset to zero when the clock signal is high, and an evaluation cycle, during which the circuit outputs the adder function when the clock signal is low. The circuit uses a combination of 12 pass-transistors to better implement the full adder logic function with the maximum of a NMOS threshold voltage drop. Moreover, the circuit has no direct connection to the power-supply node and so this can possibly save the power dissipation. Our new adder outperforms other 1-bit full adder structures in terms of power-delay factor, according to simulation results. [ABSTRACT FROM AUTHOR]

The relationship between the dielectric constant and leakage current of materials often exhibits a negative correlation. However, to sustain Moore's Law, the semiconductor industry necessitates novel materials that simultaneously possess a high dielectric constant and low leakage current, meeting the shrinking demands of electronic components. In this study, a high-performance hafnium-based thin film capacitor achieved through the collaborative effects of bottom electrode engineering and ion doping. Tungsten (W) as the bottom electrode, with its chemically inert nature and low thermal expansion coefficient, proves advantageous in improving interface quality and promoting the generation of the high- k phase in HfO 2. Concurrently, yttrium (Y) ion doping contributes to stabilizing the high- k phase of HfO 2 , reducing non-lattice oxygen, and enhancing the disorderliness of the dielectric thin film. By synergistically integrating these factors, the hafnium-based thin film capacitor achieves a high dielectric constant of 36.6 while maintaining minimal leakage current (Electric field ∼ 6 MV/cm, J ∼ 10−8 A/cm2) and a high charge storage capacity (U rec ∼ 104.4 J/cm³). These research findings open a promising pathway for the development of novel hafnium-based materials with broad applicability and exceptional dielectric performance. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium-ion batteries (LIBs) and electrical double-layer capacitors (EDLCs) are widely used in commercial energy storage systems, but each has inherent limitations. To overcome these limitations, the lithium-ion capacitor (LIC) has emerged as a hybrid energy storage device, combining the benefits of LIBs and EDLCs. However, the introduction of active lithium into LICs poses challenges due to lithium's reactivity and instability. In this study, we propose a dual wet chemical prelithiation strategy to enhance LIC performance. By wet chemically prelithiating both the activated carbon cathodes and hard carbon anodes, significant improvements are achieved compared to traditional prelithiation methods. The dual prelithiation approach outperforms electrochemical prelithiation in terms of energy storage performance, cycle life, and process simplification. LICs with dual wet chemically prelithiated electrodes demonstrate the highest energy density and retain a substantial portion of reversible capacity even at high discharge rates. The strategy exhibits fast kinetics and wide operational stability. In contrast, LICs with metallic lithium anodes or electrochemically prelithiated hard carbon anodes exhibit inferior performance and limited cycle life. The dual wet chemical prelithiation strategy represents a breakthrough in LIC technology, offering superior performance, cycle stability, and scalability. It holds promise for alkali-ion energy storage systems and drives advancements in electrochemical energy storage technology. [ABSTRACT FROM AUTHOR]

[Display omitted] Aqueous ammonium-ion capacitors (AAICs) are promising for large-scale energy storage owing to low cost and inherent safety, while their practical applications are suffered from performance under extreme environment. Low ion conductivity and high viscosity, as well as freezing of the electrolyte, are the main issues for the electrochemical performance failure at low temperatures. In this work, the AAICs were assembled with commercial carbon electrodes and antifreeze electrolyte, where the electrolyte with a freezing point lower than −115 °C is developed by using Ethylenediamine (EDA) as an additive with a volume ratio of 50 % to an aqueous solution of 0.5 M NH 4 Cl. This antifreeze electrolyte displays a superior ionic conductivity of 8.58 mS cm−1 and a weaker viscosity of 8.16 mPa s at low temperatures. Furthermore, the spectroscopic investigations and molecular dynamics (MD) simulations demonstrate that the addition of EDA can break the hydrogen bonds of water molecules and modulate the solvation structure. Therefore, the assembled AAICs with electrolytes of 0.5 M NH 4 Cl (50 %-EDA) could be operated at wide-temperature conditions steadily, exhibiting excellent capacity, rate performance and good cycling stability. This work provides a simple and effective strategy for wide-temperature energy storage devices. [ABSTRACT FROM AUTHOR]

The two-dimensional layered Ti 3 C 2 T x and N-doped Carbon Nanotube Hollow Polyhedron were tightly anchored together by strong electrostatic adsorption, which ensures the complexity of the multilevel structure and high electronic conductivity and fast transport channels. [Display omitted] • N-doped carbon nanotube hollow polyhedron/Ti 3 C 2 T x prepared with hierarchical multilevel structures. • Electrochemical performance enhancement due to rational heat treatment temperature and "electron sharing" mechanism. • Co 3 O 4 -CNT-800/Ti 3 C 2 T x provides exceptional lithium storage properties with a stabilized structure. The matching of long cycle life, high power density, and high energy density has been an inevitable requirement for the development of efficient anode materials for lithium-ion capacitors (LICs). Here, we introduce an N -doped carbon nanotube hollow polyhedron structure (Co 3 O 4 -CNT-800) with high specific surface area and active sites, which is anchored with two-dimensional (2D) Ti 3 C 2 T x nanosheets with metallic conductivity and abundant surface functional groups by electrostatic adsorption to form a hierarchical multilevel hollow semi-covered framework structure. Benefiting from the synergistic effect between Co 3 O 4 -CNT-800 and Ti 3 C 2 T x , the composites exhibit superior energy storage efficiency and long cycling stability. The Co 3 O 4 -CNT-800/Ti 3 C 2 T x electrodes exhibit a high specific capacity of 817C/g at a current density of 0.5 A/g under the three-electrode system, and the capacity retention rate is 91 % after 5000 cycles at a current density of 2 A/g. Additionally, we assembled Co 3 O 4 -CNT-800/Ti 3 C 2 T x as the anode and Activated carbon (AC) cathode to form LIC devices, which showed an electrochemical test result of 90.01 % capacitance retention after 8000 cycles at 2 A/g, and the maximum power density of the LIC was 3000 W/kg and the maximum energy density was 121 Wh/kg. This work pioneered the combination of N -doped carbon nanotube hollow polyhedron structure with two-dimensional Ti 3 C 2 T x , which provides an effective strategy for preparing LIC negative electrode materials with high specific capacitance and long cycling stability. [ABSTRACT FROM AUTHOR]

A capacitance multiplier is an active circuit designed specifically to increase the capacitance of a passive capacitor to a significantly higher capacitance level. In this paper, the use of a voltage differencing differential difference amplifier (VDDDA), an electronically controllable active device for designing grounded and floating capacitance multipliers, is proposed. The capacitance multipliers proposed in this study are extremely simple and consist of a VDDDA, a resistor, and a capacitor. The multiplication factor ( K c ) can be electronically controlled by adjusting the external bias current ( I B ). It offers an easy way of controlling it by utilizing a microcontroller for modern analog signal processing systems. The multiplication factor has the potential to be adjusted to a value that is either less than or greater than one, hence widening the variety of uses. The grounded capacitance multiplier can be easily transformed into a floating one by utilizing Zc-VDDDA. PSpice simulation and experimentation with a VDDDA realized from commercially available integrated circuits were used to test the performance of the proposed capacitance multipliers. The multiplication factor is electronically adjustable, ranging in approximation from 0.56 to 13.94. The operating frequency range is approximately three frequency decades. The realization of the lagging and leading phase shifters using the proposed capacitance multiplier is also examined and proven. The results reveal that the lagging and leading phase shifts are electronically tuned via the multiplication factor of the proposed capacitance multipliers. [ABSTRACT FROM AUTHOR]

Materials offering high energy density are currently desired to meet the increasing demand for energy storage applications, such as pulsed power devices, electric vehicles, high-frequency inverters, and so on. Particularly, ceramic-based dielectric materials have received significant attention for energy storage capacitor applications due to their outstanding properties of high power density, fast charge–discharge capabilities, and excellent temperature stability relative to batteries, electrochemical capacitors, and dielectric polymers. In this paper, we present fundamental concepts for energy storage in dielectrics, key parameters, and influence factors to enhance the energy storage performance, and we also summarize the recent progress of dielectrics, such as bulk ceramics (linear dielectrics, ferroelectrics, relaxor ferroelectrics, and anti-ferroelectrics), ceramic films, and multilayer ceramic capacitors. In addition, various strategies, such as chemical modification, grain refinement/microstructure, defect engineering, phase, local structure, domain evolution, layer thickness, stability, and electrical homogeneity, are focused on the structure–property relationship on the multiscale, which has been thoroughly addressed. Moreover, this review addresses the challenges and opportunities for future dielectric materials in energy storage capacitor applications. Overall, this review provides readers with a deeper understanding of the chemical composition, physical properties, and energy storage performance in this field of energy storage ceramic materials. [ABSTRACT FROM AUTHOR]

The health management of railway signal equipment in the high-speed railway is a key link between intelligent operation and maintenance. Accurately predicting the health state of compensation capacitors is of great significance to ensure the reliable work of track circuits. This paper proposes an improved deep neural network algorithm focusing on the problem of long-term accurate health forecasts for compensation capacitors. First, establishing a transmission state model for degradation mechanism mining, the difference function that can quantitatively evaluate features is defined by piecewise processing cab signaling receiving voltage. Introducing the degradation model, predictive driving under both model and data is implemented. Then, the convolutional neural networks and bidirectional long–short-term memory are combined and improved to construct a novel artificial intelligence combination strategy, while parameters are optimized based on the sparrow search algorithm. Finally, facing the conditional repair of compensation capacitors, we set a reasonable threshold for the occurrence of hidden dangers to complete fault warning. This novel and practical approach effectively explores the procedure of prognosis and health management, while the refined maintenance will better utilize current monitoring information, helping the intelligence and accuracy of safety control decision-making. [ABSTRACT FROM AUTHOR]

Black phosphorus (BP) has been recognized as an alluring fast‐charging anode for batteries/supercapacitors due to its substantial theoretical capacity, propitious lithiation potential, and large interlayer spacing. Nonetheless, it is encumbered by challenges of low electronic conductivity, momentous volume expansion (≈300%), and pernicious shuttle effect induced by soluble polyphosphides. Here a BP heterostructure covalent bonded by metallic antimony (Sb) is showed, which can promote the reaction dynamics of BP and greatly ameliorate the cycling performance. Robust P─Sb covalent bonds are methodically engineered to regulate the Femi level, endowing enhanced electronic conductivity. The in situ generated Li7SbO6 ionic conductor in the P/Sb interface during the lithiation process ensures the fast Li+ transport. Furthermore, Sb offers strong anchoring and chemical adsorption capability on soluble lithium polyphosphides, preventing the shuttle issue. As a result, a lithium‐ion capacitor (LIC) full‐cell based on Sb@BP/C anode demonstrates a superior energy density of 174.3 W h kg−1 and a power density of 23.7 kW kg−1, as well as exceptional reversible capacity retention. This work provides insights into the regulation of reaction kinetics and chemical adsorption capability of BP, offering guidance for designing high‐capacity and stable BP‐based anodes. [ABSTRACT FROM AUTHOR]

With the widespread use of batteries, their increased performance is of growing in importance. One avenue for this is the enhancement of ion diffusion, particularly for solid‐state electrolytes, for different ions such as lithium (Li+) and magnesium (Mg2+). Unraveling the origin of better cation diffusion in confined ionic liquids (ILs) in a polymer matrix (ionogels) is compared to that of the IL itself. Ionic conductivity measured by electrochemical impedance spectroscopy for ionogels (7.0 mS cm−1 at 30 °C) is very close to the conductivity of the non‐confined IL (8.9 mS cm−1 at 30 °C), that is, 1‐ethyl‐3‐methyimidazolium bis(trifluorosulfonyl)imide (EMIM TFSI). An even better ionic conductivity is observed for confined EMIM TFSI with high concentrations (1 m) of lithium or magnesium salt added. The improved macroscopic transport properties can be explained by the higher self‐diffusion of each ion at the liquid‐to‐solid interface induced by the confinement in a poly‐vinylidenedifluoride (PVDF) polymer matrix. Upon confinement, the strong breaking down of ion aggregates enables a better diffusion, especially for TFSI anion and strongly polarizing cations (e.g., Li+, Mg2+.). The coordination number of these cations in the liquid phase confirmed that Li+ and Mg2+ interact with the polymer matrix. Moreover, it is a major result that the activation energy for diffusion is lowered. [ABSTRACT FROM AUTHOR]

A mathematical model is presented for the optimisation of an Electromagnetic Halbach Array (EHA) for wireless power transfer. The mathematical model is based on Biot‐Savart's law of magnetic field in a current‐carrying square loop. The model is validated through static electromagnetic simulations in ANSYS Maxwell and found to be accurate and effective when predicting the magnetic field within the EHA box. To verify the analytical and simulation results, an EHA was fabricated, and experimental verification was carried out. The results show that the mathematical model can be widely used in the analysis and design optimisation of EHAs of any size and with diverse parameters in the case of single‐layer square spiral planar coils. [ABSTRACT FROM AUTHOR]

This article explores the measurement of electric fields in parallel plate capacitors. It explains the concept of parallel plate capacitors and their applications in experiments related to electric charges. The article acknowledges that real-life capacitors do not meet ideal conditions and presents standard formulas for ideal capacitors. It also discusses a simple experiment using a charged bead to measure the electric field inside and outside a parallel plate capacitor, along with the theoretical framework and equations involved. The authors conducted experiments to measure the electric field in both regions and discovered the presence of a field outside the capacitor due to the fringing effect. The study provides a theoretical explanation and a practical apparatus for measuring the electric field of a parallel plate capacitor. The article was authored by Taehun Jang, Hyejin Ha, Sang Ho Sohn, and Jungmin Moon, with Sang Ho Sohn being a professor of physics at Kyungpook National University in South Korea. [Extracted from the article]

In the realm of medium/high voltage applications, the modular multilevel converter with an active power filter (APF-MMC) emerges as a technology that eliminated the inherent voltage fluctuations of larger sub-module (SM) capacitors. However, the introduced APF circuit in each phase can only deal with power in even frequencies, and the APF-MMC cannot be directly applied in the field of motor drives with low-frequency operation. In this paper, based on the APF-MMC topology, by adding two high-frequency variables as control degrees of freedom, the base frequency power is transferred to high-frequency power, which can considerably minimize the capacitor voltage ripple in the low-frequency region of the topology. In addition, the influence of the injected high-frequency variables on the output characteristics of the topology is eliminated by controlling the APF circuit as hardware degree of freedom. Its equivalent circuit and operating principle are introduced in detail. Concurrently, a control method is proposed for the APF circuit, ensuring seamless operation of the converter. Finally, through a combination of simulation and experimental results, it is demonstrated that the APF-MMC topology surpasses the conventional MMC in its efficacy under low-frequency operation. [ABSTRACT FROM AUTHOR]

Currently, many inverters employ inductors to boost the AC voltage. However, this leads to increased current distortion and limits the voltage boosting capability of the inverter. To address the above issue, a triple two-level inverter is proposed in this paper. The proposed inverter adopts a switched-capacitor boost circuit to boost the AC output voltage and to generate a multi-level voltage. Simultaneously, a three-phase full-bridge circuit is assigned to convert the DC voltage into AC voltage. In addition, a novel space vector modulation strategy is introduced to achieve capacitor voltage self-balance. Finally, simulation and experimental platforms have been established to verify the effectiveness of proposed inverter. The obtained results show that the proposed inverter meets the requirements for the expected inverter. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes a new extendable multicell topology based on the conventional quasi‐Z‐source converter (QZSC). The proposed topology has a multicell scheme and employs an active switched capacitor/inductor (ASC/SL) network. Therefore, it is entitled extended multicell ASC/SL QZSC (EMc‐ASC/SL‐QZSC). The proposed topology is augmented by cascading a modular cell consisting of two capacitors, an inductor, and a diode. The EMc‐ASC/SL‐QZSC offers significant advantages over existing QZSC‐based configurations. It has a high boosting capability that results in a wider output voltage range while simultaneously reducing voltage stress on capacitors and switching devices, all without losing voltage gain. Furthermore, this topology effectively reduces input current ripple, which contributes to a smoother charging current profile for capacitors, reducing electromagnetic interference (EMI) and improving overall efficiency. The practicality and performance of the EMc‐ASC/SL‐QZSC topology are comprehensively assessed through extensive numerical simulations and experimental verification, utilizing a laboratory‐built prototype. [ABSTRACT FROM AUTHOR]

This paper proposes a unique sensor for detecting total ionizing dose (TID) on metal–oxide–semiconductor (MOS) devices. The proposed capacitive radiation sensor is based on commercial 180 nm complementary metal-oxide semiconductor (CMOS) technology. The sensor parameters of 180 nm length (L) and 20 nm oxide thickness (TOX) have been finalized based on simulation and mathematical analysis. Low and high radiation doses ranging from 100 rad to 1 Mrad are used to characterize it. The sensor's sensitivity for 0–10 krad is 20 mV/krad, 10 krad–100 krad is 3.9 mV/krad, and 100 krad–1 Mrad is 0.6 mV/krad when threshold shift is considered into account. Analysis of fixed oxide charge and interface trap charge generation due to ionizing radiation is done. Because interface traps are crucial to device performance, this device is evaluates using traps between 1 E06 cm−3 and 1 E14 cm−3 for realistic performance. Every interface trap exhibits a threshold voltage (VT) shift. Visual technology computer-aided design (TCAD) simulator was used to build, study, and evaluate a capacitive radiation sensor that might be used as a dosimeter for TID monitoring. [ABSTRACT FROM AUTHOR]

In this study, the aim is to evaluate three-phase (3φ) three-level (3L) neutral point clamped AC/DC rectifier for high-power applications. The rectifier analysis has been simulated using a new modified carrier-based level-shifted PWM technique. The 3L-NPC rectifier, which uses the new level-shifted PWM technique, is compared with the classical triangular carrier-based PWM signal. This new PWM technique provides low output voltage ripple, low total harmonic distortion (THD) for input current, unit input power factor, a well-regulated DC bus voltage and capacitor voltage balance for the NPC rectifier which is considered for implementation in high-power applications. This proposed modified carrier-based PWM is highly successful for 3L-NPC rectifier which is rated from 75 to 350 kW power applications. The system simulation results demonstrate the validity and flexibility of the proposed new carrier-based level-shifted PWM method for NPC rectifier in high-power applications. [ABSTRACT FROM AUTHOR]

A cross-coupled cascode feedback design for a frequency compensated operational transconductance amplifier (OTA) is presented here. This OTA is able to achieve a power supply rejection ratio (PSRR) 93 dB (DC) and common mode rejection ratio (CMRR) 41.41 dB (DC) with very low value of compensation capacitors 0.1pF driving a large load of 400pF||2.2kΩ. The proposed OTA design is simulated in 180 nm technology using Electric VLSI tool for validating its performance. The simulated results, PSRR 93 dB at 1 kHz, 83.42 dB at 1 MHz, 71.23 dB at 1 GHz are noted. Further simulated results, CMRR 41.41 dB at 1 kHz, 41.97 dB at 1 MHz and 70.79 dB at 1 GHz are also observed. Small signal and transient performances are analyzed and post-layout simulations bring out the following results: DC gain of 43.21 dB, unity-gain-frequency (UGF) of 27 MHz, Phase Margin of 48.50, slew-rate (+) of 4.63 V/μs and slew-rate (−) of 1.00 V/μs. Additionally, the circuit occupies an area of 0.014 mm 2 and the power consumption observed is 3.17 mW. [ABSTRACT FROM AUTHOR]

This paper presents layer‐by‐layer additive manufacturing (AM) of molten metal microdroplets and dielectric materials to fabricate multilayer hybrid circuit boards featuring interdigitated 3D capacitors. The printed metal lines have a low resistance of 5 mΩ/mm, 12 times lower than state‐of‐the‐art conductive inks. Exploiting the advantages of Sn‐based oxide as an ideal candidate for Electrical Energy Storage Systems (ESS), we successfully fabricated an out‐of‐plane capacitor module using a combination of polymer and metal materials. The fabrication process exhibited an exceptional aspect ratio of 16, illustrating the successful incorporation of 20 metal layers in the out‐of‐plane capacitor module. Q factor obtained for the 3D capacitor was in the range of 66–500. Additionally, a fully automated printing technique was employed to produce a multilayer hybrid electrical printed circuit board (PCB), eliminating the need for post‐processing. This streamlined approach presents an efficient and comprehensive solution for the one‐stop printing of intricate electrical circuits. © 2024 The Authors. IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

[Display omitted] Lithium ion capacitors (LICs) are a new generation of energy storage devices that combine the super energy storage capability of lithium ion batteries with the satisfactory power density of supercapacitors. The development of high-performance LICs still faces great challenges due to the unbalanced reaction kinetics at the anode and cathode. Therefore, it is an inevitable need to enhance the electron/ion transfer capability of the anode materials. In this paper, to obtain a superior-rate and high-capacity Ni 3 S 2 -based anode, highly conductive Ti 3 C 2 T x MXene sheets were introduced to sever as the carrier of Ni 3 S 2 nanoparticles and simultaneously an amorphous carbon layer which coats onto the surface of Ni 3 S 2 nanoparticles was in-situ generated by the carbonization of dopamine reactant. The as-synthesized Ni 3 S 2 /Ti 3 C 2 T x /C composite exhibits a high specific surface area (112.6 m2/g) because of the addition of Ti 3 C 2 T x that can reduce the aggregation of Ni 3 S 2 nanoparticles and the in-situ generated amorphous carbon layer that can suppress the growth of Ni 3 S 2 nanoparticles. The Ni 3 S 2 /Ti 3 C 2 T x /C anode possesses a remarkable reversible discharge specific capacity (626.0 mAh/g under 0.2 A/g current density), which increases to 1150.8 mAh/g after 400-cycle charge/discharge measurement at the same measurement condition indicating eminent cyclability, along with superior rate capability. To construct a superior-performance LIC device, a sterculiae lychnophorae derived porous carbon (SLPC) cathode with an average discharge specific capacity of 73.4 mAh/g@0.1A/g was prepared. The Ni 3 S 2 /Ti 3 C 2 T x /C//SLPC LIC device with optimal cathode/anode mass ratio has a satisfactory energy density ranging from 32.8 to 119.1 Wh kg−1 at the corresponding power density of 8799.4 to 157.5 W kg−1, together with a prominent capacity retention (95.5 %@1 A/g after 10,000 cycles). [ABSTRACT FROM AUTHOR]

In this work, we show that a magnon spin capacitor can be realized at a junction between two exchange coupled ferromagnets. In this junction, the buildup of magnon spin over the junction is coupled to the difference in magnon chemical potential, realizing the magnon spin analogue of an electrical capacitor. The relation between magnon spin and magnon chemical potential difference directly follows from considering the magnon density–density interaction between the two ferromagnets. We analyze the junction in detail by considering spin injection and detection from normal metal leads, the tunneling current across the junction, and magnon decay within the ferromagnet, showing that such a structure realizes a magnon spin capacitor in series with a spin resistor. Choosing yttrium iron garnet as the ferromagnet, we numerically calculate the magnon spin capacitance which ranges from picofarad to microfarad, depending on the area of the junction. We therefore conclude that the magnon spin capacitor could directly be of use in applications. [ABSTRACT FROM AUTHOR]

In recent years, liquid–solid triboelectric nanogenerator (LSTENG) has attracted great attention. However, its low average power density and long charging time limit the practical application of this technique. Here, for the first time, a liquid–solid triboelectric nanogenerator combined with external charge‐pumping method (ECP‐LSTENG) is proposed. Compared to traditional LSTENGs, a charge storage capacitor is added in this ECP‐LSTENG to store the output charges from the pumping generator. Then, a charge extraction capacitor is formed by the spreading and shrinking processes of falling droplet, while the charging and discharging process between charge storage and extraction capacitors can generate displacement current output for external circuit. Meanwhile, it is found that a special charged droplets adhesion phenomenon happens at the liquid–solid interface, which seriously hinders the continuous output of ECP‐LSTENG. To overcome this limitation, a special coaxial deceleration commutation component is designed to ensure continuous output of the ECP‐LSTENG. Finally, the peak power density of a droplet (50 µL) reaches 231.8 W m−2, surpassing the highest research record to date by 1.43 times. This ECP‐LSTENG provides a different approach for the future development of large‐scale integrated raindrop generators for efficient raindrop energy harvesting. [ABSTRACT FROM AUTHOR]

A flexible triple-band and polarization-insensitive rectifying metasurface (RMS) is presented in this article. The surface consists of three parts: a periodic metal unit with integrated diodes, a DC filter composed of series inductor and parallel capacitor, and a load resistor. Due to the direct integration of rectifying diodes and interconnected branches within and between the units, complex matching networks can be eliminated and the overall structure is simplified. A 6 × 6 array is fabricated and measured. The results show that at a low input power of 0 dBm, the RMS has efficiency of 51.81%, 44.25%, and 42.01% at 2.9 GHz, 5.2 GHz, and 5.77 GHz, respectively. The efficiency remains consistent under different polarization angles, demonstrating the polarization insensitivity property of RMS. Additionally, the flexible substrate enables high efficiency in the S-band and Wi-Fi bands even under a certain range of bending, revealing its superior flexibility and adaptability. Therefore, it is well suited for ambient energy harvesting and wireless self-powered miniaturized internet of things devices. [ABSTRACT FROM AUTHOR]

[Display omitted] Coupling TiO 2 within N -doped porous carbon (NPC) is essential for enhancing its Na+ storage performance. However, the role of different N configurations in NPC in improving the electrochemical performance of TiO 2 is currently unknown. In this study, melamine is deliberately incorporated as a pore-forming agent in the self-assembly process of metal organic framework precursors (NH 2 -MIL-125(Ti)). This intentional inclusion of melamine leads to the one-pot and in-situ formation of highly active edge-N, which is vital for the development of TiO 2 /NPC with exceptional reactivity. Electrochemical performance characterization and density functional theory (DFT) calculation indicate that the interaction between TiO 2 and pyridinic-N enriched NPC can effectively narrow the bandgap of TiO 2 /NPC, thereby significantly improving electron/ion transfer. Additionally, the abundant mesoporous channels, high N content and oxygen vacancies also contribute to the fast reaction kinetics of TiO 2 /NPC. As a result, the optimized TiO 2 /NPC-M, with high proportion of pyridinic-N (44.1 %) and abundant mesoporous channels (97.8 %), delivers high specific capacity of 282.1 mA h−1 at 0.05 A g−1, superior rate capability of 177.3 mA h−1 at 10 A g−1, and prominent capacity retention of 89.3 % over 5000 cycles even under ultrahigh 10 A g−1. Furthermore, the TiO 2 /NPC-M//AC sodium ion capacitors (SIC) device achieves a high energy density of 136.7 Wh kg−1 at 200 W kg−1. This research not only offers fresh perspectives on the production of high-performance TiO 2 -based anodes, but also paves the way for customizing other active materials for energy storage and beyond. [ABSTRACT FROM AUTHOR]

With the rapidly growing demand for clean energy and energy interconnection, there is an urgent need for rapid and high-capacity energy storage technologies to realize large-scale energy storage, transfer energy, and establish the energy internet. Supercapacitors, which have advantages such as high specific capacitance, fast charging and discharging rates, and long cycle lifetimes, are being widely used in electric vehicles, information technology, aerospace, and other fields. The performance of supercapacitors is crucially dependent on electrode materials. These can be categorized into electric double-layer capacitors and pseudocapacitors, primarily made from carbon and transition metal oxides, respectively. However, effectively monitoring the physicochemical properties of electrode materials during preparation and processing is challenging, which limits the improvement of supercapacitors' performance. Plasma materials preparation technology can effectively affect the materials preparation processing by energetic electrons, ions, free radicals, and multiple effects in plasma, which are easily manipulated by operation parameters. Therefore, plasma material preparation technology is considered a promising method to precisely monitor the physicochemical and electrochemical properties of energy storage materials and has been widely studied. This paper provides an overview of plasma materials preparation mechanisms, and details of the plasma technology application in the preparation of transition metal hybrids, carbon, and composite electrode materials, as well as a comparison with traditional methods. In conclusion, the advantages, challenges, and research directions of plasma materials preparation technology in the field of electrode materials preparation are summarized. [ABSTRACT FROM AUTHOR]

A novel fluorine-free electrolyte comprising a solution of lithium bis(oxalato)borate in ethyl isopropyl sulfone is presented. It is characterized by its safety and non-toxic properties, along with the capability to effectively suppress the anodic dissolution of aluminum. Successful high-temperature application of this electrolyte in combination with various capacitor- and battery-like electrode materials is shown. Further utilization in a lithium-ion capacitor and a lithium-ion battery is demonstrated. To the best of the knowledge, the lithium-ion capacitor presented in this work represents the first entirely fluorine-free device suitable for high-temperature applications. When operating at 60 °C, this device delivers a maximum energy output of 169 Wh kg-1 AM at a power of 200 W kg-1 AM and even 80 Wh kg1 AM at 10 kW kg-1 AM, along with the ability to retain 80% of its initial capacitance after 3500 cycles at 5 A g-1. As such, this novel electrolyte is a promising alternative to conventional fluorine-containing configurations since its performance is capable to match or even surpass that of most similar laboratory-scale LICs. [ABSTRACT FROM AUTHOR]

Metallized film capacitors (MFCs) are widely used in the power electronics industry due to their unique self-healing (SH) capability. SH performance is an essential assessment for MFC reliability verification in industrial production. The SH phenomenon of metallized films usually occurs rapidly in a very short period, and its real-time evolution details are often difficult to capture and analyze. In this paper, a test system for the SH performance of metallized films for capacitors was constructed. The system consists of three components: a voltage–current characteristic testing and current pulse capture device, a microscopic image real-time acquisition device, and an integrated analysis processing device. Through the voltage–current characteristic testing and current pulse capture device, the electrical parameters of the SH point, such as SH times, breakdown field strength, SH current, and SH energy, are obtained; through a microscopic image real-time acquisition device, the real-time spatial positioning of the SH point was obtained, and the interconnection between the morphology of the SH point and the electrical properties was established. The relationship between the SH point and the temperature distribution was further established using thermal imaging technology, which lays the foundation for a thorough and timely assessment and analysis of the failure mechanism and the real-time evolution of the metallized film SH process. This significantly improves the effectiveness of SH property research. [ABSTRACT FROM AUTHOR]

Multiple pulse charging modules were designed and tested for synchronous use in scaled experiments. The pulse chargers are each capable of charging a nanofarad-sized capacitive load to 100 kV in less than 10 µs. This is achieved by initially charging a microfarad-sized capacitor to a maximum of 3 kV, then, using a thyristor switch, discharging the capacitor into two transformers paralleled on the primary side. Each transformer steps the voltage up to 50 kV, with the transformer having opposing polarities and a common neutral on the secondary. Thus, the full 100 kV is obtained by placing the nanofarad-sized capacitor between the +50 and −50 kV terminals. The pulse chargers use a microcontroller to monitor and control the pulse charger in addition to communicating with the user as well as other pulse chargers. For increased battery life, each pulse charger is kept in a low-power state while not in use. Upon startup, the pulse chargers automatically detect the number of modules in the system, the position of itself in the system, and the timing delays associated with each pulse charger in the system. This information is essential for synchronous charging and provides individual information and controls for the pulse chargers. [ABSTRACT FROM AUTHOR]