Solid Conductors Research Articles

Boosting Water Oxidation on Novel Oxygen Electrode Via Surface Metal Exsolution in Protonic Ceramic Electrochemical Cell

The protonic ceramic electrochemical cell (PCEC) is an emerging and attractive technology that converts energy to hydrogen using solid oxide proton conductors at intermediate temperatures. At this temperature range, the water oxidation reaction (WOR) and oxygen evolution reaction (OER) are dominant for the overall electrode reaction while the development of electrode materials is limited and primarily reply on the knowledge from the conventional oxygen-ion conducting counterpart. Here, we developed a novel Ruddlesden-popper (R-P) electrode that presented excellent electrocatalytic activity and durability, resulted in higher hydrogen production efficiency. The present study could provide a new perspective for materials design and bring more research opportunities in the field.

(Digital Presentation) (La0.7-xNdx )Sr0.3Co1-YFeyO3- δ (x = 0.35, y = 0.2) a Novel Perovskite Type Air Electrode Material for Protonic Conducting Solid Oxide Cell (H-SOC)

Proton conducting solid oxide cell (H-SOC) is a highly efficient energy conversion device converting electrical energy into hydrogen by splitting water using solid oxide proton conductor at intermediate temperature range (500-700 0C) [1]. To enhance electrochemical performances in terms of efficient hydrogen generation, robust and durable air electrode materials are required to facilitate faster water oxidation and oxygen reduction reaction, which are the key steps for both electrolyser and fuel cell at a lower temperature [2-3]. In the present study, we have developed ‘La’ and ‘Nd’ A-site co-doped strontium cobaltite and cobalt ferrite: La0.35Nd0.35Sr0.3Co0.8Fe0.2O3-δ(LNSCF) a perovskite type cathode material exhibiting higher electrical and electrochemical performances. The electrical and O2- ion conductivity of the material shows metallic nature, and the highest conductivity values are 973 S cm-1 and 0.318 S cm-1 respectively at 400 oC. The higher value of electrical and ionic conductivity is attributed to highly efficient Co2+ to Co3+ and Fe3+ to Fe4+ transition. Electrochemical impedance spectroscopy analysis of the symmetrical cell (LNSCF/Zirconium and Yttrium doped Barium Cerate (BZCY)/LNSCF) revealed the value of Area Specific Resistance (ASR) to be 0.14, 0.47 and 3.06 Ω cm2 at 800,700 and 600 oC respectively. When operated in H-SOFC mode with humidified hydrogen as fuel and Air (3%H2O) as oxidant, the LNSCF based single cell: Ni-BZCY/BZCY (385m)/ LNSCF+BZCY achieves a maximum current density of 522, 383, and 231mA/cm2 at 800, 700, and 600 oC, respectively at 0.002 V. Whereas, in H-SOEC mode a maximum current density of -1380, -862 and -517 mA/cm2 are obtained at 800, 700, and 600 oC, respectively at 2.5 V. The contribution of different ions (O2- and H2+) and electrons (e-) in the electrochemical performances are evaluated using ion-blocking cells. The figure (1) below represents the Current Density versus Voltage (i-V) characteristic attributes for both H-SOFC and H-SOEC.

Origins and Influences of Voids in Composite Cathodes for All-Solid-State Batteries

With the exit from fossil-fuel energy becoming more and more urgent, advanced batteries are highly sought after and all-solid-state batteries (ASSBs) are seen as a promising technology potentially enabling lithium metal or reservoir-free anode designs which promote the energy density.Despite high research interest in the field, ASSBs still perform below expectations, the main challenges being elevated interfacial resistances, microstructure effects and processing, particularly at large scale. While the build-up of high resistances due to void formation upon lithium stripping at the anode side is increasingly understood, the void formation and its evolution in the composite cathode as well as the effects on the cell performance are widely unknown.Why consider voids in the cathode at all?In contrast to conventional, liquid electrolytes, solid ion conductors (such as thiophosphates) do not easily infiltrate voids and cracks in the cathode1. They possess a proper particle morphology and, depending on the solid electrolyte particle size distribution, its suitability to the active material particle sizes and morphologies the electrode structure that forms upon manufacturing can be quite different and influences the ion and electron transport as well as the charge transfer capabilities2-5. Experimentally determined void fractions in the composite typically range from 3 to 40 vol%6,7 and are therefore far away from being negligible.Apart from the void formation at manufacturing, scanning electron microscope (SEM) cross sections of cycled composites have also shown that the volume changes of LiNixCoyMn(1-x-y)O2 active material can lead to contact loss at the interface of the solid electrolyte and the active material8 which reinforces the importance of understanding the origins and the influences of voids on the cell performance.In this talk, we will discuss these, mainly from the modeling perspective including percolation network models4, flux-based simulations of the effective conductivity5 and electrochemical charge simulations based on the finite-element method9. Additionally, we use focused ion beam(FIB)-SEM tomography for the reconstruction of cathodes with different microstructures obtained by changing the particle size of the solid electrolyte. We investigate the influence of the solid electrolyte particle size distribution on the void space fraction and distribution and provide guidelines for further cathode optimization. Ruess, R.; Schweidler, S.; Hemmelmann, H.; Conforto, G.; Bielefeld, A.; Weber, D. A.; Sann, J.; Elm, M. T.; Janek, J., J. Electrochem. , 2020, 167, 100532.Minnmann, P.; Quillman, L.; Burkhardt, S.; Richter, F. H.; Janek, J., Electrochem. Soc., 2021 , 168, 040537.Jiang, W.; Zhu, X.; Huang, R.; Zhao, S.; Fan, X.; Ling, M.; Liang, C.; Wang, L., Energy Mater, 2022 , 12, 2103473.Bielefeld, A.; Weber, D. A.; Janek, J., Phys. Chem. C, 2019 , 123, 1626-1634.Bielefeld, A.; Weber, D. A.; Janek, J., ACS Appl. Interfaces, 2020 , 12, 12821-12833.Shi, T.; Zhang, Y.-Q.; Tu, Q.; Wang, Y.; Scott, M. C.; Ceder, G., Mater. Chem. A, 2020 , 8, 17399-17404.Ates, T.; Keller, M.; Kulisch, J.; Adermann, T.; Passerini, S. Energy Storage Mater., 2019 , 17, 204-210.Koerver, R.; Aygün, I.; Leichtweiß, T.; Dietrich, C.; Zhang, W.; Binder, J. O.; Hartmann, P.; Zeier, W. G.; Janek, J., Mater., 2017 , 29, 5574-5582.Bielefeld, A.; Weber, D. A.; Ruess, R.; Glavas, V.; Janek, J., Electrochem. Soc., 2022 , 169, 020539. Figure 1

Dependence of surface charge density on curvature of surface of conductive body with complicated shape

In the paper, a surface curvature of an odd-shaped solid conductor is under investigation. The correlation between the surface charge density and the surface curvature along the surface is analysed theoretically. The key result is that the surface charge density reaches a maximum at a location that is different from where the surface curvature is maximum. This new result has implications for scanning tunnel microscopy development and field-ion microscopy.

Gallium‐Based Liquid–Solid Biphasic Conductors for Soft Electronics

AbstractSoft and stretchable electronics have diverse applications in the fields of compliant bioelectronics, textile‐integrated wearables, novel forms of mechanical sensors, electronics skins, and soft robotics. In recent years, multiple material architectures have been proposed for highly deformable circuits that can undergo large tensile strains without losing electronic functionality. Among them, gallium‐based liquid metals benefit from fluidic deformability, high electrical conductivity, and self‐healing property. However, their deposition and patterning is challenging. Biphasic material architectures are recently proposed as a method to address this problem, by combining advantages of solid‐phase materials and composites, with liquid deformability and self‐healing of liquid phase conductors, thus moving toward scalable fabrication of reliable stretchable circuits. This article reviews recent biphasic conductor architectures that combine gallium‐based liquid‐phase conductors, with solid‐phase particles and polymers, and their application in fabrication of soft electronic systems. In particular, various material combinations for the solid and liquid phases in the biphasic conductor, as well as methods used to print and pattern biphasic conductive compounds, are discussed. Finally, some applications that benefit from biphasic architectures are reviewed.

Planck Formula for Black-body Radiation: Derivation and Applications

At the end of the 19th century, German physicist Victor Brooks first proposed black hole radiation. He found that objects emit electromagnetic waves when they are heated. Brooks found that the spectral density of electromagnetic waves is proportional to the temperature of the body, which is called blackbody radiation. The research of blackbody radiation began in the middle of the 19th century, studying radiator and radiation standards to meet the needs of industrial applications. The experimental results show that, especially by interpreting the spectral distribution of Planck's formula, many new physics and concepts have emerged, and many important material concepts, quantum mechanics, quantum theory of solid conductors, induction emission, quantum statistics, etc. have been developed. This study enriches thermodynamics and provides insights into the nature of light. The first aim of this paper is to derive the Planck’s Law using two different methods: one is by following the Planck’s derivation, while the other is by using Planck’s interpretation of his formula. The second aim of this paper is to use the Planck’s Law to derive Wien’s Law and Stefan’s Law.

Nanophase separated, grafted alternate copolymer styrene-maleic anhydride as an efficient room temperature solid state lithium ion conductor

All solid-state lithium metal batteries (ASSLMBs) based on polymer solid electrolyte and lithium metal anode have attracted much attention due to their high energy density and intrinsic safety. However, the low ionic conductivity at room temperature and poor mechanical properties of the solid polymer electrolyte result in increased polarization and poor cycling stability of the Li metal batteries. In order to improve the ionic conductivity at room temperature while maintaining mechanical strength, we combine the conductivity of short chain polyethylene oxide (PEO) and strength of styrene-maleic anhydride copolymer (SMA) to obtain a grafted block copolymer with nanophase separation structure, which has room temperature ionic conductivity up to 1.14 × 10−4 S/cm and tensile strength up to 1.4 MPa. Li||Li symmetric cell can work stably for more than 1500 h under the condition of 0.1 mA/cm2. Li||LiFePO4 full cells can deliver a high capacity of 151.4 mAh/g at 25 °C and 0.2 C/0.2 C charge/discharge conditions, showing 85.6% capacity retention after 400 cycles. Importantly, the all solid state Li||LiFePO4 pouch cell shows excellent safety performance under different abuse conditions. These results demonstrate that the nanophase separated, grafted alternate copolymer electrolyte has huge potential for application in Li metal batteries.

Polymers with Intrinsic Microporosity as Solid Ion Conductors for Solid‐State Lithium Batteries

AbstractSolid‐state electrolytes (SSEs) with high ionic conductivity and superior stability are considered to be a key technology for the safe operation of solid‐state lithium batteries. However, current SSEs are incapable of meeting the requirements for practical solid‐state lithium batteries. Here we report a general strategy for achieving high‐performance SSEs by engineering polymers of intrinsic microporosity (PIMs). Taking advantage of the interconnected ion pathways generated from the ionizable groups, high ionic conductivity (1.06×10−3 S cm−1 at 25 °C) is achieved for the PIMs‐based SSEs. The mechanically strong (50.0 MPa) and non‐flammable SSEs combine the two superiorities of outstanding Li+ conductivity and electrochemical stability, which can restrain the dendrite growth and prevent Li symmetric batteries from short‐circuiting even after more than 2200 h cycling. Benefiting from the rational design of SSEs, PIMs‐based SSEs Li‐metal batteries can achieve good cycling performance and superior feasibility in a series of withstand abuse tests including bending, cutting, and penetration. Moreover, the PIMs‐based SSEs endow high specific capacity (11307 mAh g−1) and long‐term discharge/charge stability (247 cycles) for solid‐state Li−O2 batteries. The PIMs‐based SSEs present a powerful strategy for enabling safe operation of high‐energy solid‐state batteries.

Polymers with Intrinsic Microporosity as Solid Ion Conductors for Solid-State Lithium Batteries.

Solid-state electrolytes (SSEs) with high ionic conductivity and superior stability are considered to be a key technology for the safe operation of solid-state lithium batteries. However, current SSEs are incapable of meeting the requirements for practical solid-state lithium batteries. Here we report a general strategy for achieving high-performance SSEs by engineering polymers of intrinsic microporosity (PIMs). Taking advantage of the interconnected ion pathways generated from the ionizable groups, high ionic conductivity (1.06×10-3 S cm-1 at 25 °C) is achieved for the PIMs-based SSEs. The mechanically strong (50.0 MPa) and non-flammable SSEs combine the two superiorities of outstanding Li+ conductivity and electrochemical stability, which can restrain the dendrite growth and prevent Li symmetric batteries from short-circuiting even after more than 2200 h cycling. Benefiting from the rational design of SSEs, PIMs-based SSEs Li-metal batteries can achieve good cycling performance and superior feasibility in a series of withstand abuse tests including bending, cutting, and penetration. Moreover, the PIMs-based SSEs endow high specific capacity (11307 mAh g-1 ) and long-term discharge/charge stability (247 cycles) for solid-state Li-O2 batteries. The PIMs-based SSEs present a powerful strategy for enabling safe operation of high-energy solid-state batteries.

2D CdPS3-based versatile superionic conductors

Ion transport in nanochannels is crucial for applications in life science, filtration, and energy storage. However, multivalent ion transport is more difficult than the monovalent analogues due to the steric effect and stronger interactions with channel walls, and the ion mobility decreases significantly as temperature decreases. Although many kinds of solid ionic conductors (SICs) have been developed, they can attain practically useful conductivities (0.01 S cm−1) only for monovalent ions above 0 °C. Here, we report a class of versatile superionic conductors, monolayer CdPS3 nanosheets-based membranes intercalated with diverse cations with a high density up to ∼2 nm−2. They exhibit unexpectedly similar superhigh ion conductivities for monovalent (K+, Na+, Li+) and multivalent ions (Ca2+, Mg2+, Al3+), ∼0.01 to 0.8 S cm−1 in the temperature range of −30 ‒ 90 °C, which are one to two orders of magnitude higher than those of the corresponding best SICs. We reveal that the high conductivity originates from the concerted movement of high-density cations in the well-ordered nanochannels with high mobility and low energy barrier. Our work opens an avenue for designing superionic conductors that can conduct various cations and provides possibilities for discovering unusual nanofluidic phenomena in nanocapillaries.

Synthesis and characterization of a new magnesium molybdates Tl1.85M0.15Mg2(MoO4)3 (M = K, Rb) with a langbeinite type structure

In this work we have successfully synthesized pure phases of Tl1.85M0.15Mg2(MoO4)3 (M = K, Rb) langbeinite powders using the solid-state reaction method. Structural characterization was carried out via the Rietveld method on the X-ray powder diffraction data. The following unit cell parameters are calculated for Tl1.85K0.15Mg2(MoO4)3: a = 10.68509(16) Å, V = 1219.93(6) Å3, and for Tl1.85Rb0.15Mg2(MoO4)3: a = 10.69463(9) Å, V = 1223.20(3) Å3. The electrical conductivity was studied by impedance spectroscopy in the [473–1010 K] temperature range and results show that the Tl1.85M0.15Mg2(MoO4)3 (M = K, Rb) were ionic solid electrolyte conductors. Results also show that Tl1.85K0.15Mg2(MoO4)3 has the highest electrical conductivity.

High single Zn-ion conductive porous organic conductors decorated with dense acidic groups via double post-synthetic sulfonations

Solid Zn-ionic conductors are one of the important components of rechargeable aqueous Zn-ion batteries. Although ion-conductive porous materials have been intensively studied due to their effective conduction pathways through large surface areas and tunable functionalities, porous material-based Zn ion conductors have been rarely reported because the strong electrostatic bonding properties of divalent Zn2+ ions generally lead to slow diffusion rates and low conductivity. Herein, we prepared porous organic polymer (POP)-based Zn-ion conductors via multiple post-synthetic modifications. The porous conductor with a large number of Zn-ion-incorporated sites exhibited a conductivity value of 3.24×10−4 S cm−1, and a transference number of 0.94, which are the highest values among other porous materials. The long-term performance of conductivity was retained for at least one week. This work highlights the remarkable effectiveness of multiple post-synthetic modifications to achieve high Zn-ion conductivity and provides the first demonstration of a Zn-ion POP conductor.

The Full-Analytical Model of AC Loss for Hollow Copper Winding in Medium Frequency Transformer

Hollow copper windings used in medium frequency transformers can not only reduce losses, but also improve heat dissipation efficiency by passing coolant through the center of the conductor. In this paper, the high-frequency AC loss of the hollow copper winding of the transformer is modeled. By decomposing the rectangular hollow copper winding with complex structure into three parallel solid copper conductor regions with regular structure, the boundary field strength and current distribution of each region are accurately solved. The effect of filling rate on loss is also considered and then an accurate analytical model of AC loss of hollow copper winding is obtained. The maximum calculation error is less than 9.8%. Simulation and experiment verify the accuracy and versatility of the model.

Reversible phase transformation and comprehensive phase diagram in SrCoO2.5+x(0≤x≤0.5) with the electric field control of oxygen content

Oxygen deficiency plays an essential role in tailoring the intriguing physical properties of complex oxides that can be harnessed in the cutting-edge energy and information technologies. A fine and continuous control of the oxygen content to modulate the rich physical properties of the complex oxides is highly desirable for both basic research and modern electronic technologies. Here, we report a recently developed ionic field-effect transistor (iFET) device with a solid oxygen ionic conductor (OIC) as the gate dielectric to finely and continuously control the oxygen content of the oxides. We realize a reversible structural transformation between brownmillerite $\mathrm{SrCo}{\mathrm{O}}_{2.5}$ and perovskite $\mathrm{SrCo}{\mathrm{O}}_{3}$ by driving oxygen ions in and out of the samples with the OICFET at room temperature. With continuously changing the oxygen content, a comprehensive phase diagram of the $\mathrm{SrCo}{\mathrm{O}}_{2.5+x}$ $(0\ensuremath{\le}x\ensuremath{\le}0.5)$ thin film from an antiferromagnetic insulator to a ferromagnetic metal is obtained in a single device. Our work provides a promising route to continuously and reversibly regulate the oxygen content and to explore unique physical states in the correlated electron oxides, and represents an important step towards the realization of a long-standing goal to develop complex oxide based devices that can be integrated with existing technologies.

Anhydrous Superprotonic Conductivity in the Zirconium Acid Triphosphate ZrH5 (PO4 )3.

The development of solid-state proton conductors with high proton conductivity at low temperatures is crucial for the implementation of hydrogen-based technologies for portable and automotive applications. Here, we report on the discovery of a new crystalline metal acid triphosphate, ZrH5 (PO4 )3 (ZP3), which exhibits record-high proton conductivity of 0.5-3.1×10-2 S cm-1 in the range 25-110 °C in anhydrous conditions. This is the highest anhydrous proton conductivity ever reported in a crystalline solid proton conductor in the range 25-110 °C. Superprotonic conductivity in ZP3 is enabled by extended defective frustrated hydrogen bond chains, where the protons are dynamically disordered over two oxygen centers. The high proton conductivity and stability in anhydrous conditions make ZP3 an excellent candidate for innovative applications in fuel cells without the need for complex water management systems, and in other energy technologies requiring fast proton transfer.

Anhydrous Superprotonic Conductivity in the Zirconium Acid Triphosphate ZrH5(PO4)3**

AbstractThe development of solid‐state proton conductors with high proton conductivity at low temperatures is crucial for the implementation of hydrogen‐based technologies for portable and automotive applications. Here, we report on the discovery of a new crystalline metal acid triphosphate, ZrH5(PO4)3 (ZP3), which exhibits record‐high proton conductivity of 0.5–3.1×10−2 S cm−1 in the range 25–110 °C in anhydrous conditions. This is the highest anhydrous proton conductivity ever reported in a crystalline solid proton conductor in the range 25–110 °C. Superprotonic conductivity in ZP3 is enabled by extended defective frustrated hydrogen bond chains, where the protons are dynamically disordered over two oxygen centers. The high proton conductivity and stability in anhydrous conditions make ZP3 an excellent candidate for innovative applications in fuel cells without the need for complex water management systems, and in other energy technologies requiring fast proton transfer.

Lithium ion transport in water-containing Li(SCN) over a wide compositional range: From water doping to hydration

This work explores the Li+ cation transport mechanisms in the system Li(SCN) · x H2O, complementary to our previous studies on crystal structures and hydration properties of lithium thiocyanate Li(SCN). Anhydrous Li(SCN) is a Schottky defective material with lithium vacancies VLi' being the dominant mobile defect. Two water incorporation mechanisms are identified: (i) At very low concentrations H2O acts as a dopant and forms H2OSCN• defects, constituting a substitutive incorporation mechanism. Doping with water not only increases the concentration of VLi' in Li(SCN), but also the vacancy mobility, making H2O-doping a special case. A complete quantitative defect chemical model is derived, including enthalpies and entropies of defect formation, association, and migration. (ii) Higher water activities induce chemical and structural changes in Li(SCN) · x H2O, i.e. hydration by reactive incorporation occurs. Single-phases as well as composites are investigated for their Li+ ion transport mechanisms. In case of x ≤ 1, defect associates determine the conductivity resulting in exceptionally high activation enthalpies. Further hydration to 1 < x < 2 creates composites of solid mono- and dihydrates, in which the low-melting diyhdrate can form percolating pathways and increase the conductivity to values as high as 7 × 10−4 S/cm at room temperature. Further increase of x leads to complete liquefaction. The entire range of x in the Li(SCN) – H2O system was studied regarding ion transport properties, identifying the individual mechanisms and temperature dependences. The results of this work deepen the understanding of hydration effects on solid ion conductors in solid state ionics, and help to elucidate transport phenomena in salt – solvent systems.

Controlling Cell Components to Design High-Voltage All-Solid-State Lithium-Ion Batteries.

All-solid-state batteries with solid ionic conductors packed between solid electrode films can release the dead space between them, enabling a greater number of cells to stack, generating higher voltage to the pack. This Review is focused on using high-voltage cathode materials, in which the redox peak of the components is extended beyond 4.7 V. Li-Ni-Mn-O systems are currently under investigation for use as the cathode in high-voltage cells. Solid electrolytes compatible with the cathode, including halide- and sulfide-based electrolytes, are also reviewed. Discussion extends to the compatibility between electrodes and electrolytes at such extended potentials. Moreover, control over the thickness of the anode is essential to reduce solid-electrolyte interphase formation and growth of dendrites. The Review discusses routes toward optimization of the cell components to minimize electrode-electrolyte impedance and facilitate ion transportation during the battery cycle.

Accounting for stray capacitances in impedance measuring cells — A mandatory step in the investigation of solid ion conductors

The determination of the dielectric response properties is essential to the investigation of solid ion conductors. The stray capacitance contributions of the measuring cell must be systematically determined and subtracted from the acquired data. Hereby, we report and discuss a general method that can be used for the accurate determination of stray capacitance in impedance measuring cells. Our method can be applied to all commercial or custom-made impedance cells or sample holders used for variable temperature conductivity measurements of fast ion conductors. After the description of the method, we present the experimental calibration done for a 2032-type coin cell sample holder. The 2032-type coin cell is a highly reliable sample holder for impedance measurements of air sensitive materials. We tested the method on a known sample and we validated it by comparing with the results obtained in a simple reference configuration. Our simple, efficient and robust method for the determination of parasitic capacitive contributions may serve as an example of good practice in the field of solid electrolytes, solid state batteries and dielectric materials investigations.

A Surface Conformal Laser‐Assisted Alloying Reaction for 3D‐Printable Solid/Liquid Biphasic Conductors

Recently, electronics research has made major advances toward a new platform technology facilitating form factor‐free devices. 3D printing techniques have attracted significant attention in the context of fabricating arbitrarily shaped circuits. Herein, a 3D‐printable metallic ink comprising multidimensional eutectic gallium indium (EGaIn)/Ag hierarchical particles is proposed to fabricate arbitrarily designable solid/liquid biphasic conductors that can be inherently self‐healed/chip bonded and do not suffer from liquid flood out due to their liquid and solid nature, respectively. The EGaIn/Ag hierarchical particles are designed to have plasmonic optical absorption at the visible green–red wavelength regime, which is elucidated by an optical simulation study, and also enable the direct transfer of thermal energy, generated in the vicinity of the Ag nanoparticles, to the surface of the EGaIn particles. The 3D surface conformal green laser irradiation process activates the evolution of the biphasic conductive layer from the as‐printed insulating particulate one. The chemical/physical evolution is elucidated along with a photothermal simulation study for clarifying the suppression of undesirable side reactions. It is demonstrated that the biphasic conductors formed by successive 3D printing and the surface conformal green laser irradiation process exhibit electrical properties that have thus far been unexplored in solid metallic conductors.