Capacitance Of Electrode Research Articles

ToF-SIMS sputter depth profiling of interphases and coatings on lithium metal surfaces

Lithium metal as a negative electrode material offers ten times the specific capacity of graphitic electrodes, but its rechargeable operation poses challenges like excessive and continuous interphase formation, high surface area lithium deposits and safety issues. Improving the lithium | electrolyte interface and interphase requires powerful surface analysis techniques, such as ToF-SIMS sputter depth profiling.This study investigates lithium metal sections with an SEI layer by ToF-SIMS using different sputter ions. An optimal sputter ion is chosen based on the measured ToF-SIMS sputter depth profiles and SEM analysis of the surface damage. Further, this method is adapted to lithium metal foil with an intermetallic coating. ToF-SIMS sputter depth profiles in both polarities provide comprehensive insights into the coating structure. Both investigations highlight the value of ToF-SIMS sputter depth profiling in lithium metal battery research and offer guidance for future studies.

Structurally integrated 3D vertically porous Ni@NiOx(MnOx) electrode for high-performance filter electrochemical capacitor

Structurally integrated 3D vertically porous Ni@NiOx(MnOx) electrode for high-performance filter electrochemical capacitor

Modulation of capacitive response for prussian blue analogue-based NiFeS2@polydopamine@NiCo2S4 core-shell composite electrodes of capacitors by a surface modification

Modulation of capacitive response for prussian blue analogue-based NiFeS2@polydopamine@NiCo2S4 core-shell composite electrodes of capacitors by a surface modification

Influence of the Electrolyte pH on the Double Layer Capacitance of Polycrystalline Pt and Au Electrodes in Acidic Solutions

Influence of the Electrolyte pH on the Double Layer Capacitance of Polycrystalline Pt and Au Electrodes in Acidic Solutions

Insights into the specific capacitance of CNT-based supercapacitor electrodes using artificial intelligence.

In this study, the specific capacitance characteristics of a carbon nanotube (CNT) supercapacitor was predicted using different machine learning algorithms, such as artificial neural network (ANN), random forest regression (RFR), k-nearest neighbors regression (KNN), and decision tree regression (DTR), based on experimental studies. The results of the simulation verified the accuracy of the ANN algorithm with respect to the data derived from the specific capacitance of the supercapacitor module. It was observed that there was a strong correlation between the experimental results and the predictions made by the ANN algorithm. Comparative analysis showed that the developed ANN algorithm was consistently superior over other algorithms in terms of different metrics, as indicated by the lowest root mean square error (RMSE) value of roughly 26.24 and the highest R 2 value of approximately 0.91. In contrast, the DTR model recorded the least reliable results in the accuracy analysis, as indicated by the highest RMSE value of about 53.46 and the lowest R 2 value of roughly 0.63. To further explore the impact of independent input parameters including pore structure, specific surface area, and I D/I G ratio on a single output parameter (particularly, the specific capacitance) the sensitivity analysis was also conducted using the SHapley Additive exPlanations (SHAP) framework. This investigation sheds light on the relative significance and effects of different input variables on the specific capacitance of supercapacitors based on CNTs. The results indicated that the ANN algorithm accurately predicted the capacitance of the CNT-based supercapacitor, demonstrating the feasibility and significance of neural network algorithms in the design of energy storage devices.

Enhancing the Performance of Nanocrystalline Nickel Cathodes via Electrodeposition for Use in Ni-Zn Batteries: Morphological and Crystallographic Structure Optimization

Abstract Rechargeable Ni-Zn batteries are gaining interest owing to their adequate performance for achieving net-zero carbon goals, low cost, and safety. However, the nickel electrode still faces significant challenges due to its limited stability and low capacity. This study investigates the development and comparison of different nickel morphologies using electrodeposition techniques. Ni nanostructures with different surface morphologies have been successfully electrodeposited by using direct (DC), pulsed (PC), and pulsed reverse (PRC) current techniques. The physical and electrochemical properties of these structures were investigated. Notably, the electrodeposition method significantly impacted the morphology and electrochemical performance of the prepared Ni nanostructures. Among the obtained structures, the PRC-deposited coating displayed a unique nano-rod morphology, exceptional uniformity, highest surface oxygen content (61.51%), and lowest surface roughness (5.12 nm). Furthermore, electrochemical measurements revealed that this structure possesses the lowest coating resistance (459.6 Ω.cm-1), minimal corrosion potential (5 mV vs SCE), enhanced oxidation/reduction peaks, the longest charge/discharge time, and highest discharge (26.2 mF.cm-2) areal capacity. These findings suggest that the Ni nanorod structure exhibits superior surface and electrochemical properties. This work offers valuable insights into how morphology and structure affect the electrochemical performance and capacity of nickel electrodes, advancing battery technologies.

MEMS Pressure Sensors with Novel TSV Design for Extreme Temperature Environments

This study introduces a manufacturing process based on industrial MEMS technology, enabling the production of diverse sensor designs customized for a wide range of absolute pressure measurements. Using monocrystalline silicon as the structural material minimizes thermal stresses and eliminates temperature-dependent semiconductor effects, as silicon functions solely as a mechanical material. Integrating a eutectic bonding process in the sensor fabrication allows for a reliable operation at temperatures up to 350 °C. The capacitive sensor electrodes are enclosed within a silicon-based Faraday cage, ensuring effective shielding against external electrostatic interference. An innovative Through-Silicon Via (TSV) design, sealed using gold–gold (Au-Au) diffusion and gold–silicon (Au-Si) eutectic bonding, further enhances the mechanical and thermal stability of the sensors, even under high-temperature conditions. The unfilled TSV structure mitigates mechanical stress from thermal expansion. The sensors exhibited excellent performance, achieving a linearity of 99.994%, a thermal drift of −0.0164% FS (full scale)/K at full load and 350 °C, and a high sensitivity of 34 fF/kPa. These results highlight the potential of these sensors for high-performance applications across various demanding environments.

Ultrabroadband integrated electro-optic frequency comb in lithium tantalate.

The integrated frequency comb generator based on Kerr parametric oscillation1 has led to chip-scale, gigahertz-spaced combs with new applications spanning hyperscale telecommunications, low-noise microwave synthesis, light detection and ranging, and astrophysical spectrometer calibration2-6. Recent progress in lithium niobate (LiNbO3) photonic integrated circuits (PICs) has resulted in chip-scale, electro-optic (EO) frequency combs7,8, offering precise comb-line positioning and simple operation without relying on the formation of dissipative Kerr solitons. However, current integrated EO combs face limited spectral coverage due to the large microwave power required to drive the non-resonant capacitive electrodes and the strong intrinsic birefringence of LiNbO3. Here we overcome both challenges with an integrated triply resonant architecture, combining monolithic microwave integrated circuits with PICs based on the recently emerged thin-film lithium tantalate (LiTaO3)9. With resonantly enhanced EO interaction and reduced birefringence in LiTaO3, we achieve a fourfold comb span extension and a 16-fold power reduction compared to the conventional, non-resonant microwave design. Driven by a hybrid integrated laser diode, the comb spans over 450 nm (more than 60 THz) with more than 2,000 lines, and the generator fits within a compact 1-cm2 footprint. We additionally observe that the strong EO coupling leads to an increased comb existence range approaching the full free spectral range of the optical microresonator. The ultra-broadband comb generator, combined with detuning-agnostic operation, could advance chip-scale spectrometry and ultra-low-noise millimetre wave synthesis10-13 and unlock octave-spanning EO combs. The methodology of co-designing microwave and photonics can be extended to a wide range of integrated EOs applications14-16.

A comparative study on the structural, chemical, morphological and electrochemical properties of α-MnO2, β-MnO2 and δ-MnO2 as cathode materials in aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are considered to be highly promising electrochemical energy storage device due to their affordability, inherent safety, large zinc resources, and optimal specific capacity. Among various cathode materials, manganese dioxide (MnO2) stands out for its high voltage, environmental benignity, and theoretical specific capacity. This study systematically investigates the phase formation and structural parameters of α-MnO2, β-MnO2, and δ-MnO2 synthesized via hydrothermal method, employing Rietveld refinement. FTIR and Raman spectroscopy confirms Mn-O and O-H bond formation. BET analysis reveals surface areas, and pore size distribution is calculated with BJH method. High-resolution XPS spectra exhibit a spin energy split of ~ 11.9 eV for Mn 2p confirming the presence of MnO2. Electrochemical studies shows an initial discharge capacities of 230.5, 188.74 and 263.30 mAh g− 1 at 0.1 A g− 1 for α-MnO2, β-MnO2 and δ-MnO2. The EIS spectra revealed the capacitive behaviour and electrode reaction kinetics where a RcT value of 484.14, 327.6, 162.5 Ω for α-MnO2, β-MnO2 and δ-MnO2. These study give insights into relation of various properties of MnO2 with electrochemical performance and its viability in grid storage applications.Graphical

A New Self-Made 16-Channel Capacitive Electrocardiography System: An Investigation and Validation for Non-Contact Electrodes.

Generally, the electrocardiography (ECG) system plays an important role in preventing and diagnosing heart diseases. To further improve the amenity and convenience of using an ECG system, we built a customized capacitive electrocardiography (cECG) system with one wet electrode, sixteen non-contact electrodes, two ADS1299 chips, and one STM32F303-based microcontroller unit (MCU). This new cECG system could acquire, save, and display the ECG data in real time. The bias feedback as a critical technique was routed to the left hand with the wet Ag/AgCl electrode, which could greatly suppress the power line noise. After all artifacts were removed, the ECG signals could be discerned clearly. We demonstrated that the ECG signals acquired with the capacitive electrodes were similar to those with the wet electrode. Thus, we successfully provide a new configuration for cECG monitoring at home or in a clinical setting.

In Situ Characterization of Competitive (De)Lithiation in Silicon/Graphite Composite Electrodes via Electrode Curvature Measurement

AbstractIn silicon/graphite (Si/Gr) composite electrodes for lithium‐ion batteries, which have recently garnered significant attention, the competitive (de)lithiation between Si and Gr is recognized as crucial for understanding the internal electrochemical processes. In this work, an in‐situ method to characterize this competitive behavior is proposed, utilizing a self‐developed electrode curvature measurement system. After validating the parallel electrode configuration and the model battery, curvature measurements are simultaneously conducted on the parallel Si and Gr cantilevered electrodes throughout electrochemical cycling. Subsequently, by calibrating the correlation between capacity and curvature of the Gr electrode, the capacity evolution of Si and Gr within the Si/Gr electrode is determined, shedding light on the underlying competitive (de)lithiation behavior. During lithiation, the process transitions from “Si‐dominant” to “Gr‐dominant” and eventually reaching a “synchronous” stage. For delithiation, it moves from “Gr‐dominant” to “Si‐dominant”. The method proposed in this work, based on the measurement of macroscopic electrode deformation, offers a novel perspective for characterizing competitive (de)lithiation in electrodes with multiphase active materials.

Effects of structural design, interface optimization, and processing on the performance of lithium battery anode silicon nanomaterials

With an emphasis on the advancements in anode material research, this article offers a comprehensive summary of the major technologies used in lithium-ion batteries, a common type of electrochemical energy storage device. Because silicon has both benefits, such as low cost and high theoretical specific capacity, and significant drawbacks, including electrode pulverization and capacity loss due to volume expansion, it is the main focus of this study. This article goes into great detail on the use of silicon material nanosizing to enhance silicon anode performance, discussing how reducing particle size can mitigate the negative effects of volume changes during cycling. However, the section on compositing and structural design processes lacks sufficient depth, which limits the understanding of how these processes can further improve anode stability and efficiency. Furthermore, the article does not comprehensively cover the diverse methods utilized to enhance silicon anode performance, such as the incorporation of conductive additives or protective coatings. The challenges associated with the practical applications of silicon nanoparticles, such as scalability and cost-effectiveness, are examined in detail; nevertheless, the prospects for further research and technological advancements in these areas are not sufficiently addressed. This paper calls for more in-depth studies and innovations in compositing techniques, structural optimization, and practical solutions to realize the full potential of silicon anodes for advanced energy storage.

Passivated Zn Powders as Metal Anode

AbstractImpacted by heavy corrosion and poor connections, zinc (Zn) powders have rarely been considered as the raw materials of Zn‐ion aqueous batteries (ZABs). Nonetheless, the ease of controlling loadings of Zn powders entitles ZABs to better capacity match between negative and positive electrodes. Here, a simple and rapid chemical solution passivation method is reported, which leads to a thin, dense, and conformal passivation layer on Zn powder surface. The passivation layer suppresses parasitic reactions of Zn powder anode, mitigates corrosions, and extends the calendar life. Mixing with well‐dispersed carbon nanotubes, the passivated Zn powder anode is able to cycle 100 h under 3 mA cm−2 and 3 mAh cm−2 at depth of discharge of 41.3%. Besides, the anode with negative/positive electrode capacity ratio of 5.95 improves the energy density of the Zn powder||MnO2 full cell to 70 Wh Kg−1. Such a simple “one‐step” passivation method is believed to be a “drop‐in” technique applied in the scalable manufacture of ZABs.

Improved capacitance of NiO and nanoporous silicon electrodes for micro-supercapacitor application

We investigated the NiO/PS/Si and the NiO/Si electrodes to highlight the effect of the PS porous silicon on the enhancement of the electrode performance. We elaborated the PS with the stain etching method, whereas the NiO nickel oxide was synthesized using sol–gel and deposited through the spin coating technique. We showed that PS porous silicon significantly increased the active surface area and improved the electrical and electrochemical properties. Thus, we obtained promising results for NiO/PS/Si. The effective series resistance and interfacial resistances were reduced from 1.8 Ω cm2 and 42 Ω cm2 to 0.05 Ω cm2 and 0.29 Ω cm2 from NiO/Si to NiO/PS/Si, respectively. The capacitance increased from 12.34 µF cm−2 for NiO/Si to 9.64 mF cm−2 for NiO/PS/Si. We found similar capacity values from the CV cyclic voltammetry curves and IS impedance spectroscopy Nyquist plots. We obtained equivalent effective series resistance values from the charge–discharge and Nyquist plots, confirming our results. The NiO/PS/Si electrode showed good stability with only a 3% loss for 5000 galvanostatic cycles. The energy efficiency is estimated from the charge–discharge curves to be 91%.

W/WO3/TiO2 Multilayer Film with Elevated Electrochromic and Capacitive Properties.

Electrochromic capacitors, which are capable of altering their appearances in line with their charged states, are drawing substantial attention from both academia and industry. Tungsten oxide is usually used as an electrochromic layer material for electrochromic devices, or as an active material for high-performance capacitor electrodes. Despite this, acceptable visual aesthetics in electrochromic capacitors have almost never been achieved using tungsten oxide, because, in its pure form, this compound only displays a onefold color modulation from transparent to blue. Herein, we have designed W/WO3/TiO2 multilayer films by a magnetron sputtering device. The impact of TiO2 layer on the optical and electrochemical properties was investigated. The results show that the optimum thickness of the TiO2 layer is 10 nm. The as-prepared film displays a high coloration efficiency (CE) of 74.2 cm2 C-1, a high areal capacitance of 32.0 mF/cm2, an excellent rate performance (with the areal capacitance still retaining 87% of the maximum capacitance at a current density of 1 mA/cm2), and a high cycle life (with a capacity retention of 91% after 1000 cycles).

Mesoporous gold decorated MXene (Ti3C2Tx) flexible composite films for photo-enhanced solid-state micro-supercapacitors

Unique mesoporous Au NPs improved the capacitance, electrical conductivity, cycling stability and photocurrent response of MXene-based film electrodes.

A lithiophilic interphase enabled by thiophenol additive for stable lithium metal anode

Lithium metal is regarded as a highly promising anode material owing to its ultrahigh theoretical capacity and low electrode potential. Unfortunately, significant concerns including poor Coulombic efficiency (CE) and uncontrolled Li dendritic growth severely hinder its development. Constructing a stable solid electrolyte interphase (SEI) on the electrode surface has been considered a practical and effective approach to settle the previous issues. In this study, 4-(trifluoromethyl)thiophenol (TFTP), an organic thiophenol, is introduced as an electrolyte additive to generate a lithiophilic organosulfur interphase with lithiophilic S sites through in situ reaction, guiding uniform Li nucleation and Li plating. Additionally, the generation of LiF/Li3N-rich layer during the cycling further facilitates homogeneous Li deposition. Therefore, the reliable SEI results in a uniform Li morphology and rapid kinetic of Li deposition. Benefiting from the TFTP electrolyte, the Li–Li symmetric cell exhibits a long-lasting lifespan of 1200 hours, and the full cell coupling with sulfur cathode shows a remarkable discharge capacity of 733.6 mAh g−1 after 200 cycles.

Polythiophene side chain chemistry and its impact on advanced composite anodes for lithium-ion batteries.

In the development of high-performance lithium-ion batteries (LIBs), the design of polymer binders, particularly through manipulation of side-chain chemistry, plays a pivotal role in optimizing electrode stability, ion transport, and adaptability to the volume changes during cycling. In particular, poly[3-(potassium-4-butanoate)thiophene-2,5-diyl] (P3KBT) increases magnetite and silicon capacity and cycling stability. This work explores the impact of polythiophene alkyl sidechain length on anode characteristics, aiming to enhance performance in LIBs. P3KBT and its alkyl chain alternatives, poly[3-(potassium-5-pentanoate)thiophene-2,5-diyl] (P3KPT) and poly[3-(potassium-6-hexanoate)thiophene-2,5-diyl] (P3KHT) were systematically investigated over 300 charge-discharge cycles. The experiments were designed to assess how varying side-chain length affects the stability, ion transport, and capacity retention of the electrodes. The results revealed that P3KHT, with its longer alkyl chain, exhibited superior capacity retention and reduced charge-transfer resistance after 300 cycles compared to its shorter chain analogs. The findings demonstrate that tailored side chains can improve ion transport, structural integrity, and capacity retention, addressing critical challenges in LIBs such as capacity fade and electrode degradation. This research contributes to the development of next-generation LIBs with enhanced performance and reliability.

"Bridge" interface design modulates high-performance cellulose-based integrated flexible supercapacitors.

Flexible supercapacitors offer significant potential for powering next-generation flexible electronics. However, the mechanical and electrochemical stability of flexible supercapacitors under different flexibility conditions is limited by the weak bonding between neighboring layers, posing a major obstacle to their practical application. In this paper, natural coniferous pulp cellulose was successfully modified with ethylenediamine and NiSe2/Cell-NH2/MoS2 cellulose flexible electrodes (NCMF) were fabricated by phase transfer and hydrothermal methods. The amino-modified cellulose (Cell-NH2) acts as a "bridge" between NiSe2 and MoS2, significantly enhancing the interfacial bonding strength of the flexible electrode. The integrated flexible electrode exhibited a high area capacitance (2475 mF/cm2), strong tensile strength (10.3 MPa), and excellent cycling stability (92.1 % capacitance retention after 2500 cycles). The sandwich-structured monolithic supercapacitor achieved both a high electrode capacitance (56.78 F/cm2) and a high energy density (1971.53 μWh/cm2), while maintaining long cycling life (72.73 % capacitance retention after 2000 cycles) and large deformation capability. This makes it suitable for stable power supplies in electronic products and opens new possibilities for the flexible wearable industry. This technology enables stable power supplies for electronic products and paves the way for advancements in the flexible wearable industry.

Molecular mobility of thin films of poly(bisphenol-A carbonate) capped and with one free surface: from bulk-like samples down to the adsorbed layer.

The molecular mobility of thin films of poly(bisphenol A carbonate) (PBAC) was systematically investigated using broadband dielectric spectroscopy, employing two distinct electrode configurations. First, films were prepared in a capped geometry between aluminum electrodes employing a crossed electrode capacitor (CEC) configuration, down to film thicknesses of 40 nm. The Vogel temperature, derived from the temperature dependence of relaxation rates of the α-relaxation, increases with decreasing film thickness characterized by an onset thickness. The onset thickness depends on the annealing conditions, with less intense annealing yielding a lower onset thickness. Additionally, a broadening of the β-relaxation peak was observed with decreasing thickness, attributed to the interaction of phenyl groups with thermally evaporated aluminum, resulting in a shift of certain relaxation modes to higher temperatures relative to the bulk material. A novel phenomenon, termed the slow Arrhenius process (SAP), was also identified in proximity to the α-relaxation temperature. For films with thicknesses below 40 nm, nanostructured electrodes (NSE) were utilized, incorporating nanostructured silica spacers to establish a free surface with air. This free surface causes an enhancement in the molecular mobility for the 40 nm sample, preserving the β-relaxation as a distinct peak. The α-relaxation was detectable in the dielectric loss down to 18 nm, shifting to higher temperatures as film thickness is decreased. Notably, the onset thickness for the increase in Vogel temperature was lower in the NSE configuration compared to the CEC setup, attributed to the presence of the polymer-air interface.