Electron Conductivity Research Articles

Laser-Regulated Iridium-Diffused Nitrogen-Carbon Sites for Enhanced Hydrazine-Assisted Alkaline Seawater Splitting and Zinc-Hydrazine Batteries.

The current study presents a quick and simple method for synthesizing Ir nanoclusters decorated on an N-doped carbon (NC) matrix via pulsed laser ablation in liquid, followed by pyrolysis. The resulting Ir-NC material acts as a dual-functional electrocatalyst, efficiently facilitating hydrogen generation through the hydrazine oxidation reaction (HzOR) and the hydrogen evolution reaction (HER) in alkaline seawater. The optimized Ir-NC-2 catalyst exhibits a low operating potential of 23mV versus the reversible hydrogen electrode for HzOR and a remarkably low overpotential of 24mV for HER, achieving a current density of 10mAcm-2 in alkaline seawater, surpassing the performance of the Pt/C catalyst. Notably, the Ir-NC-2 catalyst also demonstrates superior dual-functionality in overall hydrazine-assisted seawater splitting, requiring only 0.1V at 10mAcm-2 while maintaining stability. Moreover, density functional theory calculations reveal that the strong electronic interaction between the Ir nanoclusters and the NC matrix enhances mass transfer and electron conductivity, significantly boosting HER activity and accelerating the kinetics of hydrazine dehydrogenation. Consequently, the Ir-NC-2 catalyst performs efficiently in a Zn-hydrazine battery, achieving high energy efficiency of 95.5% and demonstrating excellent stability for 120h (360 cycles), indicating its potential for practical applications.

Dual-mode electrochemical and electrochemiluminescence detection of dopamine based on perylene diimide self-assembly material.

The self-assembly materialN,N-bis-(3-dimethyl aminopropyl)-3,4,9,10-perylene tetracarboxylic acid diimide (PDI) isreported to show electrochemical (EC)/electrochemiluminescence (ECL) property for designing new dual-mode dopamine (DA) sensors. K2S2O8 significantly improved the EC reduction current at -0.346V and ECL intensity at -0.25V of thePDI self-assembly material. DA largely decreased the EC reduction current and ECL intensity of this homogeneous EC/ECL material due to the competitive consumption of K2S2O8 in theoxidization process of DA and the low electron conductivity of polyDA formed through the oxidization of DA by K2S2O8. In addition, the ECL quenching mechanism involved an energy-transfer process resulting from the collision between the produced o-benzoquinone species (oxidization of DA) and the excited state of PDI, which decreased the ECL intensity. This homogeneous EC/ECL material showed linear EC current response for DA from 5.0 nM to 50.0 µM with a detection of limit of 2.7 nM and linear ECL response for DA from 1.0 nM to 100.0 µM with a detection of limit of 0.41 nM. Theproposed dual-mode EC/ECL sensors also showed good feasibility in urine sample analysis.

Design and Synthesis of Sb-Doped CuS@C Hollow Nanocubes as Efficient Anode Materials for Sodium-Ion Battery.

Copper sulfide has received widespread attention for application as anode materials in sodium-ion batteries due to their potent capabilitiess and eco-friendly properties. However, it is a challenge to achieve a high rate capability and long cycle stability owing to the heterogeneous transfer of sodium ions during charge-discharge, the interior poor electron conductivity and repeated volumetric expansion of copper sulfide. In this study, Sb-doped copper sulfide hollow nanocubes coated with carbon shells (Sb-CuS@C) was designed and constructed as anode nanomaterials in sodium-ion batteries. Thanks to the intrinsic good electron conductivity and chemical stability of carbon shells, Sb-CuS@C possesses a higher overall electron transfer as anode material, avoids agglomeration and structural destruction during the cycling. As a result, the synthesized Sb-CuS@C achieved an excellent reversible capacity of 595 mA h g-1 after 100 cycles at 0.5 A g-1 and a good rate capability of 340 mA h g-1 at a higher 10 A g-1. DFT calculations clarify that the uniformly doped Sb would act as active sodiophilic nucleation sites to help adsorbing sodium-ion during discharging and leading uniform sodium deposition. This work provides a new insight into the structural and componential modification for common transition-metal sulfides towards application as anode materials in sodium-ion battery.

Enhancing Li4Ti5O12 Anodes for High‐Performance Batteries: Ti3+ Induction via Plasma‐Enhanced Chemical Vapor Deposition and Dual Carbon/LLZO Coatings

AbstractLithium titanium oxide (LTO) is a promising anode material due to its ability to store lithium through intercalation reactions. However, its electrochemical performance is limited by poor electron conductivity and side reactions with the electrolyte. In this study, plasma‐enhanced chemical vapor deposition (PECVD) is employed to introduce oxygen vacancies and self‐doped Ti3+ into LTO to improve the internal conductivity. Subsequent carbon coating and aluminum‐doped lithium lanthanum zirconate garnet (LLZO) layers resulted in a multi‐layered composite denoted as LTO−L‐x. Morphological analyses using SEM and TEM demonstrated the successful growth of Al‐doped LLZO on carbon‐coated LTO. Aluminum ions in LLZO cubic structure are crucial for stabilizing the high ionic conductive phase during cooling, as confirmed by X‐ray diffraction. The dual coating layers have a significant impact on the rate capability, reducing polarization gaps and enabling higher capacities at various current rates. Long‐term cycling tests reveal the robustness of the composite, with LTO−L‐1.0 retaining 90.8 % capacity after 4000 cycles at 1.0 A g−1. This underscores the sustained high electronic and ionic conductivity facilitated by the dual coating layers. The study contributes to the design of advanced anode materials for lithium‐ion batteries, emphasizing the importance of tailored coating strategies to address conductivity and stability challenges.

Hierarchical Flower Array NiCoOOH@CoLa‐LDH Nanosheets for High‐Performance Supercapacitor and Alkaline Zn Battery

AbstractNickel oxyhydroxide based energy storage materials have been largely confined by insufficient exposure of active sites which results in low energy efficiency and poor stability. In order to resolve the problems, hierarchical flower array heterostructure NiCoOOH@CoLa‐LDH (denoted as NC@CL) nanosheets are designed with NiCo oxyhydroxide (NiCoOOH, denoted as NC) being tightly covered on CoLa layered double hydroxide (CoLa‐LDH, denoted as CL) nanosheet. This rational design creates more active sites, enlarges the electrode‐electrolyte contact area, improves electron conductivity, and prevents agglomeration during the cycling charge–discharge processes. Density functional theory calculations and differential charges concurrently illustrate that heterostructure formation optimizes the reaction kinetics and promotes electron redistribution. Benefiting from the heterogeneous structure and rich electro‐active sites caused by NC, NC@CL displays outstanding reversible specific capacitance (3228 F g−1 at 1 A g−1). The aqueous rechargeable alkaline Zn battery NC@CL//Zn exhibits a high capacity of 381.1 mA h g−1 at 0.5 A g−1 and cycling durability (98% capacity retention after cycling at 5 A g−1 for 2000 cycles). The excellent electrochemical performances indicate that NC@CL has great application potential as electrode material for aqueous energy storage device.

Zn-doped hollow cubic MnO2 as a high-performance cathode material for Zn ion batteries.

Manganese-based compounds have the characteristics of high theoretical capacity, low cost and stable performance, thus become a research hotspot for cathode materials of zinc-ion batteries (ZIBs). However, in the process of charging and discharging, it is accompanied by problems such as structural collapse and low conductivity, which resulted in severe capacity degration during cycles. In this paper, a kind of Zn2+ doped MnO2 hollow cube cathode material (Zn-MnO2) was prepared by self-sacrificing template method. The Zn2+ doped in MnO2 crystals can induce oxygen vacancies in the structure, thereby improving the structural stability ion diffusion coefficient and electrical conductivity of the material. After 100 cycles at 0.3 A g-1, the high specific capacity of 281.2 mA h g-1 is still maintained. Through ex-situ XPS and ex-situ XRD tests, the mechanism of charge-discharge process was discussed. The results show that the storage mechanism of Zn-MnO2 is H+ and Zn2+ insertion/removal and Mn3+/Mn2+ two-electron reaction pathway. The total state density (TDOS) and partial state density (PDOS) of Zn-MnO2 and MnO2 further demonstrated that the doping of Zn2+ enhanced the electron conductivity and is beneficial to the electron transfer during the electrochemical reaction.

Zn/Pt dual-site single-atom driven difunctional superimposition-augmented sonosensitizer for sonodynamic therapy boosted ferroptosis of cancer

Sonodynamic therapy (SDT) as a non-invasive antitumor strategy has been widely concerned. However, the rapid electron (e-) and hole (h+) recombination of traditional inorganic semiconductor sonosensitizers under ultrasonic (US) stimulation greatly limits the production of reactive oxygen species (ROS). Herein, we report a unique Zn/Pt dual-site single-atom driven difunctional superimposition-augmented TiO2-based sonosensitizer (Zn/Pt SATs). Initially, we verify through theoretical calculation that the strongly coupled Zn and Pt atoms can assist electron excitation at the atomic level by increasing electron conductivity and excitation efficiency under US, respectively, thus effectively improving the yield of ROS. Additionally, Zn/Pt SATs can significantly enhance ferroptosis by producing more ROS and sonoexcited holes under US stimuli. Therefore, the establishment of dual-site single-atom system represents an innovative strategy to enhance SDT in cancer model of female mice and provides a typical example for the development of inorganic sonosensitizer in the field of antitumor therapy.

Hierarchically Structured Conductive Lanthanide Metal Organic Framework Nanorods for Ultrastable Flexible Magnesium Ion Capacitors

AbstractAqueous multivalent metal ion capacitors are very attractive owing to their high capacitance, low cost, environmental benignity, and safety. Herein, hierarchically structured, conductive lanthanide metal‐organic frameworks (MOFs) assembled by nanorods for ultrastable flexible magnesium ion capacitors (MICs) is designed. Three MOFs, consisting of lanthanide metals (La, Ho, and Yb) and 2,3,6,7,10,11‐hexahydroxytriphenylene (HHTP), are structurally stabilized through the covalent bonds and electronically conductive due to π‐d conjugation. Among 3 MOFs, Ho‐HHTP electrodes in a full‐cell system achieved long‐term cyclic stability with a high capacitance retention of 65.0% after 12 000 cycles and a high Coulombic efficiency of 96.9%. Furthermore, flexible pouch cells are fabricated using Ho‐HHTP as anode, reduced graphene oxide as cathode, and poly(vinyl alcohol) (PVA)/Mg(ClO4)2 as gel electrolyte, demonstrating a low capacitance decay rate of 0.00444% per cycle during 10 000 cycles owing to the hierarchical structure and intrinsic electronic conductivity. As indicated by density functional theory and spectroscopic characterizations, Mg2+ ions are faradaically stored in the catechol part of the ligand, and Mg2+ inserted into the vacant Ho sites contributes to structural stability. Furthermore, operando 2D correlation Raman spectroscopy identified how Mg2+ ions interact with the ligand of Ho‐HHTP and demonstrated the sequential change of peak change.

Influence of exfoliation method of graphene on physical properties of graphene/High Density Polyethylene nanocomposites: Semiconductor‐like electrical conductivity, glass transition, and melting temperature

AbstractDespite the wide range of applications of polyethylene (PE), many efforts are being made to improve its properties with carbon allotropes such as graphene. The addition of graphene can improve the electrical, thermal, and mechanical properties of this polymer. Through the present study, the effects of exfoliated graphene nanoplatelets (XGNPs) and few‐layer graphene (FLG) on the electrical conductivity and thermal properties of high‐density polyethylene (HDPE) were investigated. XGNPs were synthesized by ultrasonication of graphite nanoplatelets, and FLG was synthesized by shear exfoliation of flake graphite. Finally, HDPE powder particles were coated with dispersed XGNPs and FLG. Then XGNPs/HDPE nanocomposites and FLG/HDPE nanocomposites were fabricated by compression molding. The morphology, structural, electrical, and thermal properties of the graphite, graphene, PE, and nanocomposites were observed and comparatively studied by transmission electron microscopy, field emission scanning electron microscope, x‐ray diffraction (XRD), Raman spectroscopy, and conductivity measurements. The graphene's D, G, and 2D bands were revealed by Raman spectroscopy of nanocomposites and verified the existence of the graphene in the polymer matrix. XRD revealed that the graphene did not affect the original crystalline structure of the HDPE matrix, and the Fourier‐transform infrared spectroscopy revealed that the nanocomposite was obtained without the formation of any functional groups. The electrical properties of the nanocomposites were comparatively studied. After adding XGNPs (7 wt%), volumetric electrical conductivity in a sample reached from 10−16 to 10−3 S/m. The highest volumetric conductivity, 1.1 × 10−2 S/m, that is, semiconductor‐like conductivity, was achieved after adding 7 wt% of FLG. The glass transition temperatures (Tg), melting temperatures (Tm), and thermal stability were investigated by differential scanning calorimetry and TGA, respectively, and it was concluded that Tg and Tm increase by adding the graphene. This study shows that shear exfoliation of graphene is the best and the most facile method to prepare mass‐scale graphene for the production of graphene/polyolefin nanocomposites.Highlights Two types of graphene were produced by using sonication and shear‐exfoliation. HDPE powders were coated with two types of graphene and then hot pressed. The method of (G) preparation is crucialparameter on electrical conductivity. In the sample containing 7 wt% (XGNPs), the highest conductivity is 10−3 S/m. In the sample containing 7 wt% (FLG), the highest conductivity is 10−2 S/m.

Design Lithium Exchanged Zeolite Based Multifunctional Electrode Additive for Ultra‐High Loading Electrode Toward High Energy Density Lithium Metal Battery

AbstractThe practicalization of a high energy density battery requires the electrode to achieve decent performance under ultra‐high active material loading. However, as the electrode thickness increases, there is a notable restriction in ionic transport in the electrodes, limiting the diffusion kinetics of Li+ and the utilization rate of active substances. In this study, lithium‐ion‐exchanged zeolite X (Li‐X zeolite) is synthesized via Li+ exchange strategy to enhance Li+ diffusion kinetics. When incorporated Li–X zeolite into the ultra‐high loading cathodes, it possesses i) high electron conductivity with a uniform network by reducing tortuosity, ii) decent ion conductivity attributes to modulated Li+ diffusivity of Li‐X and iii) high elasticity to prevent particle‐level cracking and electrode‐level disintegration. Moreover, Li–X zeolite at the solid/liquid interface facilitates the formation of a stable cathode electrolyte interface, which effectively suppresses side reactions and mitigates the dissolution of transition cations. Therefore, an ultra‐high loading (66 mg cm−2) cathode is fabricated via dry electrode technology, demonstrating a remarkable areal capacity of 12.7 mAh cm−2 and a high energy density of 464 Wh kg−1 in a lithium metal battery. The well‐designed electrode structure with multifunctional Li–X zeolite as an additive in thick cathodes holds promise to enhance the battery's rate capability, cycling stability, and overall energy density.

Structural Features of Porous Silicon Formed on Heavily Doped Plates of Single-Crystal Silicon with Electron Conductivity

Using scanning electron microscopy, the structures of the surface and internal regions of porous silicon obtained by anodizing heavily doped plates of single-crystal silicon with electron conductivity in a hydrofluoric acid solution at different current densities were studied. It is found that the porous silicon surface has dark gray and light gray pores, which differ in size and surface distribution density. Dark gray pores possess larger sizes, and their density is about 5–10 times less than that of light gray pores. Based on the cross-section imagery, it is shown that light gray pores correspond to underdeveloped channels of small depth, while dark gray pores are the entrance points of deep bottle-shaped channels passing from the surface into the depth of the silicon wafer. The equivalent diameters of light gray pores on the surface of porous silicon are 12–15 nm and are practically independent of the anodic current density. At the same time, the equivalent diameters of dark gray pores and average distances between their centers increase linearly from 15 to 35 nm on the surface and from 35 to 120 nm in the volume of porous silicon when the current density is increased from 30 to 90 mA/cm2. The average thickness of silicon skeleton elements is about 3 nm on the surface and increases to 5–6 nm in the volume. By setting the density of the anode current, it is possible to obtain layers of porous silicon with different structural parameters. The obtained research results have practical significance for the formation of composite materials based on porous silicon, which can be used as a porous matrix for the deposition of metals and semiconductors.

High‐performance MCNTs@MoS2(1‐x)Se2x Nanocomposites in Catalytic Hydrogen Evolution

Advances in electrocatalysis require the development of high specific surface area materials with high electron conductivity. In this study, a series of MCNTs@MoS <sub>2(1‐x)</sub>Se <sub>2x</sub> nanocomposites has been prepared for application in catalytic hydrogen evolution. A uniform growth of MoS <sub>2(1‐x)</sub>Se <sub>2x</sub> nanoflower spheres on MCNTs has been achieved, circumventing stacking and aggregation. The introduction of the conducting material accelerated the electron transport rate in the electrode reaction. Structural characterization has confirmed that S doping increased the specific surface area of the catalyst, exposing more edge defects. As a result, the MCNTs@MoS <sub>2(1‐x)</sub>Se <sub>2x</sub> nanocomposites exhibited enhanced catalytic activity.

Mechanical and Electrical Conductivity Properties of Graphene/Cu Interfaces: A Theoretical Insight.

For graphene/copper (Gr/Cu) composites, achieving high-quality interfaces between Gr and Cu (strong interfacial bonding strength and excellent electron transport performance) is crucial for enabling their widespread applications in electronic devices. This study employs first-principles calculations and the nonequilibrium Green's function method to systematically investigate the mechanical and electrical conductivity properties of Cu(111)/Gr/Cu(111) interfaces with various stacking sequences and different forms of Gr. For these interface systems, the binding energy, separation work, charge transfer, and electrical conductivity across the interface were obtained. The results show that the top-fcc interface exhibits superior interfacial properties, characterized by relatively high binding energy (-3.00 eV/C atom) and separation work (≥0.78 J/m2), a small interfacial distance (2.85 Å), and enhanced electron transport capacity (2.12 G0/nm2). A bilayer form of Gr significantly reduces electronic conductance across the Gr/Cu interface by nearly 2.46 orders of magnitude. Furthermore, point defects in Gr, especially single-vacancy defects, disrupt the traditional trade-offs between mechanical and electrical performance, simultaneously enhancing mechanical performance by 7.50-124.36% and electrical performance by 33.02%. Additionally, stress mechanisms have been proposed to further enhance the interfacial electrical conductivity of Gr/Cu composites. The present study provides a theoretical basis for exploring the engineering applications of Gr/Cu composite materials.

Effect of micropatterning with nanowire-based microcavity array on bacterial enrichment and selective distribution

The micro-patterned topography can affect bacterial enrichment and selective distribution by modifying the characteristics of material surface. In this study, we fabricated microcavity patterned silicon surfaces, and quantitatively explored the amount and distribution of Escherichia coli (E. coli) cells attached on a series of defined topographies. The results showed that E. coli cells enrichment was significantly increased on silicon nanowires-based microcavity array when compared to nanowires patterned silicon wafer. Furthermore, the microcavity diameter can control bacterial distribution by changing hydrophilic performance of interface. With the microcavity diameter of 7 µm, the cells colonized into the microcavity almost in its entirety, whilst distributed around the microcavity completely with 10 µm diameter, regardless of centre distances. This phenomenon can be explained by the Cassie-Baxter model equation according to the wettability. The distribution of bacterial enrichment changed with the silicon surfaces turning from non-wetting status to wetting status when treated with oxygen plasma to modify the hydrophobicity. These results demonstrated that microcavity patterned surface could favor bacterial enrichment on silicon and strictly confined bacterial distribution inside/outside the microcavity. Moreover, the nanowires inside microcavity can also increase electron conductivity and reduce the internal resistance, thus providing scientific evidence for the design of wearable microbial fuel cell with rational optimization and integration of different components for electronic skin.

Insulator-to-Metal Transition and Isotropic Gigantic Magnetoresistance in Layered Magnetic Semiconductors.

Magnetotransport, the response of electrical conduction to external magnetic field, acts as an important tool to reveal fundamental concepts behind exotic phenomena and plays a key role in enabling spintronic applications. Magnetotransport is generally sensitive to magnetic field orientations. In contrast, efficient and isotropic modulation of electronic transport, which is useful in technology applications such as omnidirectional sensing, is rarely seen, especially for pristine crystals. Here a strategy is proposed to realize extremely strong modulation of electron conduction by magnetic field which is independent of field direction. GdPS, a layered antiferromagnetic semiconductor with resistivity anisotropies, supports a field-driven insulator-to-metal transition with a paradoxically isotropic gigantic negative magnetoresistance insensitive to magnetic field orientations. This isotropic magnetoresistance originates from the combined effects of a near-zero spin-orbit coupling of Gd3+-based half-filling f-electron system and the strong on-site f-d exchange coupling in Gd atoms. These results not only providea novel material system with extraordinary magnetotransport that offers a missing block for antiferromagnet-based ultrafast and efficient spintronic devices, but also demonstrate the key ingredients for designing magnetic materials with desired transport properties for advanced functionalities.

Li diffusion in oxygen-chlorine mixed anion borosilicate glasses using a machine-learning simulation.

Lithium-ion conducting borate glasses are suitable for solid-state batteries as an interfacial material between a crystalline electrolyte and an electrode, thanks to their superior formability. Chlorine has been known to improve the electron conductivity of borate glasses as a secondary anion. To examine the impact of chlorine on lithium dynamics, molecular dynamics (MD) simulations were performed with a machine-learning interatomic potential (MLIP). The accuracy of the MLIP in modeling chlorine-doped lithium borate (LBCl) and borosilicate (LBSCl) glasses was verified by comparing with available experimental data on density, neutron diffraction S(q), and glass transition temperatures (Tg). While the MLIP-MD simulations underestimated the density when an isobaric-isothermal (NPT) ensemble was used, the glass models relaxed using the NPT ensemble after a melt-quench simulation employing a canonical (NVT) ensemble possessed reasonable density. The LBCl and LBSCl glass models exhibited increased lithium ion diffusion, and the ions were found to travel longer distances with an increase in the chlorine content. According to the structural analyses, it was observed that chlorine ions primarily interacted with lithium ions rather than the network formers. Consequently, lithium ions that interacted with a higher amount of chlorine showed a moderate increase in mobility. In summary, the MLIP demonstrated reasonable accuracy in modeling chlorine-containing borate glasses and enabled the investigation of the effect of chlorine on electron conductivity. In contrast, the first sharp diffraction peaks in S(q) deviated from the experimental diffractions, suggesting that additional efforts are required to accurately model the middle-range structure of the glasses.

Analysis of Thermoelectric Properties of Hot-deformed Bismuth Telluride Sintered Materials

Bismuth telluride (Bi2Te3)-based alloys are widely used for thermoelectric cooling and power generation at low temperatures, and they are the only commercially available materials for thermoelectric applications below 500 K. The rhombohedral unit cell with a large c/a lattice constant ratio consisting of - Te-Bi-Te-Bi-Te- stacked layers inevitably brings about a large anisotropy in transport properties, which is why texturing is very important in polycrystalline Bi2Te3</sub alloys for maximum performance. In this report, p and n-type polycrystalline Bi2Te3</sub alloys were synthesized and hot-deformed to investigate the effects of texturing on thermoelectric properties. Hot deformation (HD) induces the strong alignment of (001) orientations along the compression direction, and a remarkable increase in the orientation factor F of (001) orientations is observed after HD in both p and n-type materials. All of the hot-deformed polycrystalline samples showed increased electrical conductivity (σ), power factor (PF), and thermal conductivity (k) in the in-plane (IP) direction, and vice versa in the out-of-plane (OOP) direction, which makes the IP direction of the hot-deformed bodies more favorable for module fabrication in terms of power factor, for both p and n-type Bi2Te3</sub-based alloys. However, due to the different degree of anisotropy of k and σ, the figures of merit (zT) were maximized in the OOP direction in the p-type materials after HD, whereas the zTs of the n-type materials were higher in the IP direction. This occurs because the anisotropy factor of electron conduction is higher than that of hole conduction, which more than offsets the advantage of the smaller k in the c-direction of n-type Bi2Te3</sub. The maximum zT of 1.33 (OOP) and 0.90 (IP) were obtained after HD from the p and n-type Bi2Te3 alloys, respectively, which were 9.3% and 18.4% higher than those of as-sintered materials.

Bi doping induces the quantum dots to improve the supercapacitor performance of cobalt carbonate hydroxide hydrate

Cobalt carbonate hydroxide has been widely used in supercapacitor electrodes because of its excellent theoretical electrochemical properties and easy synthesis. However, in actual synthesis, its excellent electrochemical properties are often weakened due to its oxide-like properties, which restricts its further development. Herein, the Bi heteroatoms are introduced into the Co(CO3)0.5(OH)·0.11H2O, which not only modifies the microstructure, but also induces the formation of quantum dots, thus improving the performance of supercapacitors. By regulating the doping amount of Bi, the optimized Co/Bi-3:1 exhibits a specific capacitance of 680 F g−1 at 1 A g−1, which is 5.74 times than the pristine Co(CO3)0.5(OH)·0.11H2O. Furthermore, the assembled Co/Bi-3:1//activated carbon soft-pack asymmetric supercapacitor has a relatively superior power density (10547.58 W kg−1, relative to 14.06 Wh kg−1 energy density) and energy density (17.83 Wh kg−1, relative to 2146.76 W kg−1 power density). The present study demonstrates that Bi doping not only facilitates the formation of quantum dots and enhances electron conduction ability, but also regulates the microscopic morphology, thereby enhancing the electrochemical energy storage capacity of cobalt carbonate hydroxide hydrate electrode materials.

High-voltage aqueous supercapacitors enabled by polysiloxane passivation coating-modified carbon cloth electrode

The voltage window plays a crucial role in determining the energy density of supercapacitors. The limited energy density of carbon-based supercapacitors poses a significant challenge to their widespread adoption. Here, we propose a novel approach to modify carbon cloth by implementing a polysiloxane (PSiO) passivation coating. This forms an ion-conductive and electron-insulating thin film on the surface, effectively impeding electron conduction from electrode surface to electrode/electrolyte interface and suppressing electrolyte electrolysis. Consequently, an expanded voltage window is realized, thereby enhancing the energy density of aqueous carbon-based supercapacitors. The carbon cloth electrode modified with the PSiO passivation coating (CC-A-KH560) exhibits exceptional electrochemical performance, with a significantly increased 78.6 % widened applicable potential range compared to the activated carbon cloth electrode (CC-A). In a two-electrode configuration, the voltage window is broadened from 0.8 V for CC-A to 1.4 V for CC-A-KH560, and the energy density based on CC-A-KH560 is 8 times that based on CC-A. The good stability and durability are also obtained for the firm C–O–Si bonds during PSiO modification. More importantly, this design provides a generic solution of PSiO passivation coating-modified carbon electrode, applicable for diversified silicane couple agents, to realize a high-voltage energy storage performance for aqueous supercapacitors.

Impact Deposition of a Single Droplet of Low-Melting-Point Alloy as the Top Electrode for Organic Photovoltaics.

Top electrodes of organic photovoltaics (OPVs) are usually thermally evaporated in the vacuum, which is non-continuous and time-consuming and has been the bottleneck for the OPV fabrication process. Printable top electrodes that are free of vacuum, high temperature, and solvents will make OPVs more attractive. Low-melting-point alloys (LMPAs) are promising candidates for printable OPV electrodes thanks to the merits of matching work functions, high electron conductivity, high environment stability, and no need for post-treatment. Here, LMPA electrodes are directly deposited on OPVs by simply falling a single LMPA droplet onto the substrate. The LMPA droplet spreads to form a thin film with a smooth interface intimately contacting the substrate. The electrode area can be tailored by adjusting the droplet diameter or the Weber number, which is the ratio of inertia to surface tension. The interface morphology is mainly affected by the contact temperature. The degree of oxidation and charges on the droplet can also influence the electrode area and interface morphology. OPVs with droplet-impacted LMPA electrodes exhibit power conversion efficiencies of up to 16.17%. This work demonstrates the potential of single-droplet impact deposition as a simple method for printing OPV electrodes for scalable manufacturing.