Symmetric Electrodes Research Articles

Energetic and durable all-polymer aqueous battery for sustainable, flexible power

All-polymer aqueous batteries, featuring electrodes and electrolytes made entirely from polymers, advance wearable electronics through their processing ease, inherent safety, and sustainability. Challenges persist with the instability of polymer electrode redox products in aqueous environments, which fail to achieve high performance in all-polymer aqueous batteries. Here, we report a polymer-aqueous electrolyte designed to stabilize polymer electrode redox products by modulating the solvation layers and forming a solid-electrolyte interphase. Polyaniline is selected as an example for its dual functionality as a cathode or anode working by p/n doping mechanisms. This approach pioneers the application of polyaniline as an anode and enhances the high-voltage stability of polyaniline cathode in an aqueous electrolyte. The resulting all-polymer aqueous sodium-ion battery with polyaniline as symmetric electrodes exhibits a high capacity of 139 mAh/g, energy density of 153 Wh/kg, and a retention of over 92% after 4800 cycles. Spectroscopic characterizations have elucidated the hydration structure, solid-electrolyte interphase, and dual-ion doping mechanism. Large-scale all-polymer flexible batteries are fabricated with excellent flexibility and recyclability, heralding a paradigmatic approach to sustainable, wearable energy storage.

Fluorine-doped perovskite cathodes with boosted electrocatalytic activity for CO2 electrolysis

Global energy demands that have traditionally been satisfied by the use of fossil fuels have led to substantial emissions of CO2, an important greenhouse gas. Solid oxide electrolysis cells (SOECs) offer a practical approach for transforming CO2 into valuable fuels. Accordingly, creating stable electrocatalysts and perovskite cathodes capable of efficiently converting CO2 is a primary aim for the further development of SOECs. Although reconstructing active sites during CO2 electrolysis is significantly challenging, it is also constrained by our lack of understanding of this process. Herein, we introduce an innovative strategy that involves co-doping with Cu and F to better facilitate the exsolution reaction, which resulted in the formation of an advanced cathode composed of Cu-Fe alloy nanoparticles embedded in a fluorine-doped Sr2Fe1.5Mo0.5O6−δ (SFM) ceramic matrix. The in-situ electrochemical reconstruction of the SFM cathode through co-doping not only improves mass-transfer efficiency during CO2 electrolysis but also enhances the catalytic activity and durability of the ceramic cathode. A SOEC assembled with this material as a symmetrical electrode delivered 4.99 mL min−1 cm−2 of CO at 850 °C and an applied voltage of 1.8 V, which is 168 % higher than that of a pure SFM electrode. In addition, no carbon deposits were observed at the end of the reaction. The co-doping strategy delivered enhanced performance without degradation over 100 h of high-temperature operation, which suggests that it is a reliable cathode material for CO2 electrolysis. This study introduced an innovative method for improving the SOEC-electrode microstructure and developing efficient electrocatalysts for CO2 electrolysis.

Electrochemical performance of sodium compound NaNi0.4Fe0.2Mn0.4O2 as symmetrical electrode for low temperature ceramic fuel cells

The electrochemical performance and related mechanisms of NaNi0.4Fe0.2Mn0.4O2 (NNFM) as symmetrical electrode for low-temperature ceramic fuel cells were investigated. After reduction in H2 at elevated temperature, sodium compounds including NaOH molten salt are formed in the NNFM anode, which diffuses into the GDC electrolyte, creating a composite electrolyte of “GDC-sodium compounds” with high ionic conductivity. The ionic conductivity of the “GDC-sodium compounds” composite electrolyte generated in the cell with GDC/NNFM (weight ratio 8/2) composite as the electrolyte layer reached 0.116 S · cm−1 at 550 °C. The maximum power density of the cell with the “GDC-sodium compounds” composite electrolyte reaches 273 mW · cm−2 at 550 °C. The presence of molten salt in the sodium compounds enhances the electrolyte’s ionic conductivity while also contributing to the filling of internal pores and ensuring effective fuel gas sealing. The formation of sodium compounds molten salt within the cell also significantly reduces the polarization resistance associated with the electrode reactions in the electrodes on both sides of the cell.

Microstructure Evolution Analysis of Ni/YSZ Cermet Electrode using Cross-Sectional Model Cells

Abstract Degradation of solid oxide cells can be partially attributed to the microstructural changes in Ni/YSZ fuel electrodes owing to Ni migration. This study aims to evaluate the microstructural evolution of Ni/YSZ fuel electrodes as a function of the oxygen potential along the thickness direction. To this end, comb-shaped Ni-patterned electrodes were designed on the top layer of a YSZ thin film using two different systems: (a) a symmetrical Ni-patterned electrode and (b) an asymmetrical Ni–Pt electrode with a reference electrode. In the symmetrical electrode, one side of the Ni-patterned electrode operated at the fuel cell (FC) mode, exhibiting expansion that led to an increase in triple-phase boundary (TPB) length and a decrease in electrolyte width. Conversely, the Ni-patterned electrodes that operated in electrolysis (EC) mode showed a slight migration away from the electrolyte. Detailed microstructural changes in the EC mode were examined using the asymmetrical electrode, revealing a correlation between water vapor content and Ni morphology. The results suggest that the amount of water vapor adsorbed on the electrode surface causes the decrease of oxygen potential at TPB. This causes the decrease in the wettability that led to significant change of Ni microstructure across the electrode length.

Electrolyte impact on supercapacitors made off Ni2O3-Ni2S3 decorating graphitic carbon nitride

Utilizing the hydrothermal method, we have successfully synthesized a promising composite material by adorning Ni2O3-Ni2S3 onto graphitic carbon nitride (G-C3N4). This composite’s structural and morphological characteristics were thoroughly examined through various analytical parameters. SEM and TEM images depict the incorporation of Ni2O3-Ni2S3 onto the 2D sheets of G-C3N4. Employing this nanocomposite, we have fabricated a supercapacitor with symmetric electrodes. Whatman filter paper, saturated with different electrolytes—HCl, Na2SO4, and KOH—was the separator between the electrodes. A series of tests were conducted to assess the electrical performance of the supercapacitor, including charge/discharge cycles, cyclic voltammetry, impedance, and lifetime measurements. At a current density of 0.3 A g−1, distinct charge and discharge times were observed for each electrolyte: 790 s for HCl, 140 s for Na2SO4, and 358 s for KOH. The supercapacitor’s energy density (E) varied depending on the electrolyte employed. Similarly, HCl achieved optimal performance, yielding the E value of 84.8 W.h.kg-1. Conversely, Na2SO4 showed reduced values at 9.5 W.h.kg−1, while KOH had the lowest values at 5.5 W.h.kg−1. The results unmistakably establish that the supercapacitor’s performance adheres to the HCl > Na2SO4 > KOH sequence concerning the electrolytes used. Looking ahead, our team aims to advance toward developing a prototype for a supercapacitor, positioning it as a viable alternative to traditional batteries in energy storage applications.

Different enhancement of Ni doping on La0.3Sr0.7Fe0.9Ti0.1O3-δ electrodes in symmetrical solid oxide cell

Poor catalytic activity is a significant challenge that needs to be addressed to enable the effective use of perovskite electrodes in symmetrical solid oxide cell (SOC). In this study, high-activity Ni ions were doped into the La0.3Sr0.7Fe0.9Ti0.1O3-δ (LSFTi91) perovskite lattice, which endowed the materials with different facilitation effects in different atmospheres. In an oxidizing atmosphere, the introduction of Ni ions enables La0.3Sr0.7Fe0.8Ti0.1Ni0.1O3-δ (LSFTNi811) to exhibit higher conductivity and oxygen vacancy content, which enhances the adsorption and dissociation of gases. When used as symmetrical electrodes in a solid oxide electrolysis cell, the LSFTNi811 symmetric cell presents higher electrolysis performance than LSFTi91 (1.78 A cm−2 vs. 1.57 A cm−2) at 1.5 V and 800 °C. This is the highest level reported for a single-phase perovskite electrode, underlining its excellent catalytic activity. In a reducing atmosphere, although Ni doping weakens the structural stability of the material, a large number of NiFe nanoparticles precipitate the H2 reaction after material decomposition. In this situation, LSFTNi811 achieves better performance than LSFTi91 as a symmetrical electrode for the solid oxide fuel cell both before and after decomposition. Therefore, LSFTNi811 is a promising symmetrical electrode material for SOCs.

Biogenic synthesis of porous CuO nanoparticles: Synergistic effects in photocatalytic dye degradation and electrochemical energy storage applications

This study explores the biogenic synthesis of CuO nanoparticles functionalized with Solanum nigrum, using Acalypha indica leaf extract as a reducing agent. The biogenically synthesized CuO nanoparticles were comprehensively characterized by various analytical techniques, involves X-ray diffraction analysis (XRD), BET surface area analysis (BET), energy-dispersive X-ray spectroscopy (EDAX), X-ray photoelectron spectroscopy (XPS), UV–Visible spectral analysis (UV), Fourier transform infrared spectroscopy (FTIR), fluorescence spectroscopy, photocatalytic degradation, antimicrobial assay, cytotoxicity assay, electrochemical analysis, and linear sweep voltammetry studies. The XRD analysis revealed end centered monoclinic phase with a 10 nm average crystalline size. BET analysis showed a mesoporous structure with a surface area of 11.54 m2/g. XPS and EDAX confirmed the presence of Cu2+ and O2− ions. SEM and TEM images indicated spherical, and porous nanostructures. UV–Visible spectroscopy identified an active optical range of 508–518 nm (2.40–2.45 eV), suggesting potential photocatalytic activity. The photocatalytic degradation efficiencies of Methylene blue (98.8 %) and Rhodamine B (95 %) were achieved after 100 min of irradiation. Antimicrobial tests demonstrated effectiveness against Staph. aureus, E. coli, Shigella flexneri, and Candida tropicalis. The nanoparticles exhibited notable cytotoxicity against colorectal cancer cells with IC50 values of 58.66 μg/ml and 66.78 μg/ml. Additionally, a symmetric supercapacitor electrode using these nanoparticles achieved a specific capacitance of 375 Fg−1 at the current density of 1 Ag−1. This research underscores the versatile applications of biogenic CuO nanoparticles in photocatalysis, antimicrobial treatments, cancer therapy, and energy storage.

Neodymium oxide-based hybrid phase few-layer MoS2 nanocomposite as high-performance symmetric supercapacitor electrode

The two-dimensional layered materials (for example MoS2) are potential electrodes for supercapacitors with their excellent lamellar structure, high surface area, mechanical flexibility, and potential redox activity. However, due to restacking of chemical structure and low electrical conductivity of the pure MoS2 electrodes are prevented for energy storage applications. Therefore the electrodes are made up of a composite by a mixture of MoS2 and rare-earth metals significantly addressing these issues with improved electrical conductivity, large electrochemical active surface, and shorter ion-diffusion kinetics. In the present study, the MoS2 and MoS2/Nd2O3 composite were synthesized by hydrothermal method. The structural phase identification of prepared samples was accomplished by using an X-ray diffractometer (XRD) and Raman spectra. Furthermore, TEM reveals changes in the shape of nanosheets and interlayer spacing. The GCD of symmetric MoS2/Nd2O3 composite electrodes displayed remarkable charging/discharging performance, with increased stability and rate capability. The MoS2/Nd2O3 composite shows utmost Csp of 2528.18 Fg-1 at 1 Ag-1. In addition, the CV and GCD studies suggest that the electrodes exhibit pseudocapacitive behavior and excellent energy density(E) of 191 Wh kg-1 at 1474.1 W kg-1 power density(P) in 1M H2SO4. The supercapacitor device made up of MoS2/Nd2O3 composite shows greater performance in practical LED glowing applications. Therefore, the composites make advancements in energy storage devices like batteries and supercapbatteries due to their excellent energy storage, high electrochemically active surface area, and stability.

Zr and Y co-doped SrFe0.8Zr0.1Y0.1O3-δ perovskite oxide as a stable, high-performance symmetrical electrode for solid oxide cells

Symmetrical solid oxide cells (SSOCs), which use the same material for both anode and cathode, simplify the cell fabrication process and effectively resist carbon deposition and sulfur poisoning. In this study, Zr, Y co-doped SrFe0.8Zr0.1Y0.1O3-δ (SFZY) perovskite oxide is synthesized and evaluated its properties as an SSOFCs electrode. Density functional theory (DFT) indicates that the local state density of SFZY is lower than that of SrFeO3-δ (SFO). SFZY has good chemical compatibility with La0.8Sr0.2Ga0.83Mg0.17O3−δ (LSGM) electrolyte below cell operating temperature. Zr, Y co-doped SrFe0.8Zr0.1Y0.1O3-δ maintains structural stability in H2 atmosphere. At 750 ℃, the polarization resistance (Rp) of SFZY is 0.11 and 1.06 Ω cm2 in air and hydrogen atmosphere, respectively. During the Rp stability test, SFZY exhibits better stability than that of SrFeO3-δ in air and hydrogen atmosphere. At 750 ℃, the maximum power density of SFZY/LSGM/SFZY fuel cell reaches 420.1 and 258.31 mWcm−2 using H2 and wet C3H8 as fuel, respectively. In electrolytic mode, the current density of SFZY/LSGM/SFZY electrolysis cell reaches -0.55 A cm−2 at 1.3V for electrolysis of pure CO2 at 750 ℃. In summary, SFZY has a great potential as SSOCs electrode.

A niobium and tantalum co-doped perovskite electrolyte with high ionic conduction for low-temperature Ceramics Fuel cell

In recent studies, fast ionic conduction through surface doping and coating has been a favorite subject and has indicated a promising and stable strategy to optimize ions in the developed electrolytes for low-temperature ceramic fuel cells (LT-CFCs). We have designed co-doped perovskite (Nb/Ta-SrCoO3) to enhance further ionic properties using the Solid-state blending technique. The prepared SCNT (SrCoNb0.3Ta0.3O3) was used as an electrolyte sandwiched between symmetrical electrodes and delivered attractive fuel cell performance (650 mW/cm2) with better stability at the low operating temperature of 520 °C compared to other compositions of SCNT. The low grain boundary resistance manifests SCNT's high ionic conduction + microstructural properties, assisting with higher fuel cell performance. The co-doping enables the fermi-level to move towards the -ive side, establishing a space charge region constituting BIEF (built in electric field) and helping to enhance the ions' transportation through the surface and interface. This work thus points out a new type of electrolyte with a different working mechanism from previous studies. It indicates a feasible approach to developing high-performing and stable electrolytes for LT-CFCs.

Multi-metal-doped transition metal compounds for high-performance asymmetric capacitive deionization

To address the limited ion adsorption capacity of carbon-based capacitive deionization (CDI) which primarily relies on double-layer mechanism, recent efforts have focused on the rational design and development of efficient Faradaic materials for CDI applications. In this study, we synthesized and applied Co- and Mn-doped transition metal compounds (Cu₂O@MCF) as the electrodes for asymmetric CDI using a simple hydrothermal method. The synthesized electrodes were analyzed using various characterization techniques, to confirm the successful doping and structural integrity. Electrochemical performance assessments revealed significant improvements in ion-capture capacity and overall desalination efficiency. Specifically, the optimized asymmetric CDI cell configuration, consisting of Cu₂O@MCF(Cl) as an anode and Cu₂O@MCF(Na) as a cathode, led to a significant increase in salt adsorption capacity (27.42 mg/g) over conventional symmetric carbon electrode (11.22 mg/g), an increase of over 2.4 times. Furthermore, the synthesized electrodes demonstrated effective phosphate ion removal, highlighting their potential applicability in wastewater treatment. The findings suggest that multi-metal doping significantly enhances electrode performance by synergistically combining electric double-layer capacitance and pseudocapacitance effects, due to their unique morphological and electrochemical properties. These results contribute to sustainable water treatment and resource recovery efforts, showcasing the effectiveness of the materials in improving CDI performance and opening new avenues for their application in environmental cleanup and resource management.

A Self-Healing and Sweat-Chargeable Hydrogel Electrolyte for All-in-One Flexible Supercapacitors.

Flexible solid-state supercapacitors (SCs) with hydrogel as an electrolyte and separator combine the advantages of wearability and energy storage and exhibit a broad application prospect in wearable energy textiles. However, irreversible electrolyte damage and unstable electrode-electrolyte interfaces during mechanical deformations remain bottlenecks in realizing truly wearable applications. Herein, poly(acrylic acid) (PAA)-Fe hydrogels were prepared through a simple thermal polymerization strategy. The dynamic reversible metal coordination bonds between Fe3+ and carboxylic acids confers the hydrogels with excellent self-healing properties. As expected, the prepared hydrogels exhibited superior mechanical strength (tensile stress of 45.80 kPa), ionic conductivity (0.076 S cm-1), and self-healing properties. Subsequently, the SCs were constructed using composite hydrogel electrodes (MnO2@CC embedded in the PAA-Fe hydrogels) as symmetrical electrodes (marked as MSCs). The reversible metal coordination bonds between composite hydrogel electrodes formed an ultrastable electrode/electrolyte interface in the all-in-one MSCs, thus revealing excellent mechanical durability. The all-in-one MSCs delivered a remarkable specific capacitance (30.98 F g-1 at 0.2 A g-1), excellent cyclic stability (87.24% after 5000 cycles), outstanding mechanical deformation stability, and impressive electrochemical output stability after self-healing (capacitance retention of 85.34% after five cycles of cutting/self-healing). It is noteworthy that the all-in-one MSCs employed NaCl as an electrolyte, which can be obtained from human sweat. As a proof of the self-charged concept, the all-in-one MSCs can be reused in sweat, whose capacitance was maintained at 90.05% of the initial state after three repetitions. This work is expected to shine light into the design of all-in-one and fabric-based SCs and the development of wearable energy textiles.

Enhanced catalytic activity and durability of Ru–Fe alloy-modified Sr1.95Fe1.5Mo0.5O6-δ nanostructured symmetric electrode

The stable and advanced catalytic symmetrical electrode material can reduce the number of electrode exchange in hydrocarbon fuel and extend the service life of symmetrical solid oxide fuel cells (SSOFCs). In this study, Sr1.95Fe1.45Ru0.05Mo0.5O6-δ (SFRM) perovskites were developed and applied as both fuel and air electrode materials for SSOFCs for the first time. The peak power density (PPD) of SSOFC using SFRM electrodes is 583.6 mW cm−2, which is higher than that of SSOFC using SFM electrodes at 800 °C. Additionally, with an increase in reduction time, the maximum power density further increases by 20%–804.9 mW cm−2 with the exsolution of Ru–Fe antiparticles. Importantly, Ru doping results in a significant decrease in the size of exsolved nanoparticles and leads to a larger specific surface area. In the atmosphere of pure methane, Ru doped SFM increased from 130.9 to 185.1 W cm−2 compared with pure phase, and the discharge performance of SFRM electrode at 850 °C was more stable than that of SFM electrode. Thus, SFRM electrodes present a promising and viable option for enhancing the performance of SSOFCs.

Realizing enhanced photoresponse for self-powered broadband photodetector with asymmetric contacts based MoTe2/WSe2 van der Waals heterostructure

Self-powered photodetectors constructed by two-dimensional (2D) materials are significant in advanced science and technology with the growing focus on green and energy-efficient solutions. The built-in electric field in photodetector drives efficient separation and transfer of photogenerated electron–hole pairs. However, traditional metal-2D material-metal structures have more interface defects and larger Schottky barrier to hinder carrier transport. In this work, an asymmetric electrode material structure is constructed by adding graphene to provide a more efficient transport channel for photogenerated carriers. Graphene electrodes can play a variety of roles in efficient separation and collection of photogenerated carriers, reducing the barrier and improving the contact quality. Compared with the device using symmetric gold electrodes, the device prepared with asymmetric contacts show optimized performance. The MoTe2/WSe2 heterostructure exhibits brilliant self-powered photoresponse (a responsivity of 268 mA/W and a detectivity of 7.48*1011 Jones). And the rise/decay times are up to 145μs/125μs. Additionally, the detector has a broadband detection capability from visible light to near-infrared. These results provide a promising and simple way to fabricate a MoTe2/WSe2 self-powered broadband photodetector with high performance

Interconnected hierarchical 3D porous carbon derived from Saccharum officinarum L. leaf based on the synergistic effect of KOH for high performance supercapacitor

ABSTRACT Porous carbon has continuously been explored based on biomass for green energy storage due to its abundant, renewable, environmentally friendly resource, economical features, and thermal-chemical stability. Therefore, this study aimed to present porous carbon derived from sugarcane or Saccharum officinarum L. leaf as a precursor, achieved through a KOH activation strategy that combines a two-step pyrolysis process. The synthesized material exhibited an interconnected 3D hierarchical structure, a high specific surface area of 752 m2/g, and a carbon purity of 91.38%. Supercapacitor cell electrode had the highest specific capacitance of 471 F/g induced by 0.5 M KOH. Furthermore, in the 1 M H2SO4 electrolyte solution, the symmetrical supercapacitor cell electrodes produced the highest specific energy of 65.55 Wh/Kg at a specific power output of 329 W/Kg. As a result, a sustainable green method was established by using a biomass energy source that is applied as high-performance supercapacitor cell material.

AC Zeeman effect in microfabricated surface traps.

Quantum processors and atomic clocks based on trapped ions often utilize an ion's hyperfine transition as the qubit state or frequency reference, respectively. These states are a good choice because they are insensitive in first order to magnetic field fluctuations, leading to long coherence times and stable frequency splittings. In trapped ions, however, these states are still subject to the second order AC Zeeman effect due to the necessary presence of an oscillating magnetic field used to confine the ions in a Paul trap configuration. Here, we measure the frequency shift of the 2S1/2 hyperfine transition of a 171Yb+ ion caused by the radio frequency (RF) electromagnetic field used to create confinement in several microfabricated surface trap designs. By comparing different trap designs, we show that two key design modifications significantly reduce the AC Zeeman effect experienced by the ion: (1) an RF ground layer routed directly below the entire RF electrode, and (2) a symmetric RF electrode. Both of these changes lead to better cancellation of the AC magnetic field and, thus, overall reduced frequency shifts due to the AC Zeeman effect and reduced variation across the device. These improvements enable a more homogeneous environment for quantum computing and can reduce errors for precision applications such as atomic clocks.

Synergistic enhancement of ion/electron transport by ultrafine nanoparticles and graphene in Li2FeTiO4/C/G nanofibers for symmetric Li-ion batteries

Low-cost Fe-based disordered rock salt (DRX) Li2FeTiO4 is capable of providing high capacity (295 mA h g−1) by redox activity of cations (Fe2+/Fe4+ and Ti3+/Ti4+) and anionic oxygen. However, DRX structures lack transport channels for ions and electrons, resulting in sluggish kinetics, poor electrochemical activity, and cyclability. Herein, graphene conductive carbon network permeated Li2FeTiO4 (LFT/C/G) nanofibers are successfully prepared by a facile sol-gel assisted electrospinning method. Ultrafine Li2FeTiO4 nanoparticles (2 nm) and one-dimensional (1D) structure provide abundant active sites and unobstructed diffusion channels, accelerating ion diffusion. In addition, introducing graphene reduces the band gap and Li+ diffusion barrier and improves the dynamic properties of Li2FeTiO4, thus achieving a relatively mild interfacial reaction and reversible redox reaction. As expected, the LFT/C/1.0G cathode delivers a remarkable discharge capacity (238.5 mA h g−1), high energy density (508.8 Wh kg−1), and excellent rate capability (51.2 mA h g−1 at 1.0 A g−1). Besides, the LFT/C/1.0G anode also displays a high capacity (514.5 mA h g−1 at 500 mA g−1) and a remarkable rate capability (243.9 mA h g−1 at 8 A g−1). Moreover, the full batteries based on the LFT/C/1.0G symmetric electrode demonstrate a reversible capacity of 117.0 mA h g−1 after 100 cycles at 50 mA g−1. This study presents useful insights into developing cost-effective DRX cathodes with durable and fast lithium storage.

Surface-doped perovskite electrolyte for low-temperature ceramic electrochemical cells

Protonic ceramic electrochemical cells (PCECs) can be employed for power generation and sustainable hydrogen production. Lowering the PCEC operating temperature to >500 °C can facilitate its scale-up and commercialization. However, achieving high energy efficiency and long-term durability at low operating temperatures is a long-standing challenge. Here, we report a simple and scalable approach for fabricating metal ion doping into perovskite (Li-doped SrTiO3 (STO)) using the sol-gel approach and presented as a proton conducting electrolyte with lower ohmic and polarization resistance for low-temperature ceramic fuel cells. The prepared electrolyte with symmetrical electrodes attains high power densities in fuel-cell mode (∼0.65 W cm−2 at 520 °C and ∼0.20 W cm−2 at 420 °C) and exceptional current densities in steam electrolysis mode (−0.94 A cm−2 at 1.4 V and 520 °C). Additionally, five-layer devices (Ni-NCAL/BCZYYb/Li-STO/BCZYYb/NCAL-Ni) demonstrate the proton fuel cell performance of 0.55 W cm−2 at 520 °C.

Regulating the Porosity and Bipolarity of Polyimide-Based Covalent Organic Framework for Advanced Aqueous Dual-Ion Symmetric Batteries.

The all-organic aqueous dual-ion batteries (ADIBs) have attracted increasing attention due to the low cost and high safety. However, the solubility and unstable activity of organic electrodes restrict the synergistic storage of anions and cations in the symmetric ADIBs. Herein, a novel polyimide-based covalent organic framework (labeled as NTPI-COF) is constructed, featured with the boosted structure stability and electronic conductivity. Through regulating the porosity and bipolarity integrally, the NTPI-COF possesses hierarchical porous structure (mesopore and micropore) and abundant bipolar active centers (C═O and C─N), which exhibits rapid dual-ion transport and storage effects. As a result, the NTPI-COF as the electrodes for ADIBs deliver a high reversible capacity of 109.7mAhg-1 for Na+ storage and that of 74.8mAhg-1 for Cl- storage at 1Ag-1, respectively, and with a capacity retention of 93.2% over 10000 cycles at 10Ag-1. Additionally, the all-organic ADIBs with symmetric NTPI-COF electrodes achieve an impressive energy density of up to 148Whkg-1 and a high power density of 2600Wkg-1. Coupling the bipolarity and porosity of the all-organic electrodes applied in ADIBs will further advance the development of low-cost and large-scale energy storage.

Effects of surfactants on the morphologies, structures, and electrochemical activities of WO3/Ag2O nanocomposites for supercapacitor electrodes

For energy storage, supercapacitors have been extensively developed. Among them, pseudocapacitors that use faradaic reactions of conductive polymers and transition metal oxides exhibit high electrochemical performance. In this study, WO3-based electrodes for high-performance pseudocapacitors were designed with Ag2O and various surfactants, with the aim to extend of the potential range and shape control of WO3 crystals. The WO3/Ag2O nanocomposites were prepared on a carbon cloth via chemical bath deposition with different types of surfactants: cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and Pluronic F-127. Both Ag and the surfactants affected the morphology of the WO3 crystals; their crystal sizes were decreased, and the crystallinity was improved. The specific capacitance of the WO3/Ag2O nanocomposite was 621 F/g at 5 mV/s, whereas that of WO3 was 397 F/g. Furthermore, the specific capacitance of the nanocomposites increased with the use of surfactants: 960 F/g for WO3/Ag2O@Pluronic F-127, 641 F/g for WO3/Ag2O@CTAB, and 846 F/g for WO3/Ag2O@SDS at 5 mV/s. WO3/Ag2O@Pluronic F-127 had superior capacitance and exhibited a charge/discharge capacitance retention rate of 135 % after 2000 cycles at 5 A/g. The symmetric electrode configuration of WO3/Ag2O@Pluronic F-127 exhibited a maximum energy density of 85 W h kg−1 and a power density of 670 W kg−1. These results highlight the significant potential of the WO3/Ag2O@Pluronic F-127 nanocomposite electrode for future energy storage devices.