Safety of the batteries and power units used in insulin pumps: A pilot cross‐sectional study by the Association for the Study of Innovative Diabetes Treatment in Japan

Aims/Introduction

We investigated the safety of the batteries and power units used in insulin pumps in Japan.

Materials and Methods

A self‐administered questionnaire was sent to the 201 members of the Association for Innovative Diabetes Treatment in Japan.

Results

A total of 56 members responded, and among the 1,499 active devices, 66 had episodes of trouble related to the batteries and power units. The ratio of reported troubles to the number of insulin pumps was significantly higher in insulin pumps with a continuous glucose monitoring sensor compared with insulin pumps without a continuous glucose monitoring sensor (odds ratio 2.82, P < 0.05). The cause and the consequences varied. The brands of the batteries varied; alkaline batteries purchased at drug stores and other shops accounted for 19.7%. Termination of battery life within 72 h of use was reported most frequently (50.0%), suspension of the insulin pump (21.2%) and leakage of the battery fluid (4.5%) followed. A total of 53.2% of the reported insulin pumps needed to be replaced, and 37.1% of them recovered after replacement of the battery.

Conclusions

As trouble related to the batteries and power units of insulin pumps was frequent, practical guidance should be provided to respective patients regarding the use of reliable batteries, and to be well prepared for unexpected insulin pump failure.     

Button battery ingestions

Although ingestions of button batteries can have serious complications, the majority of these ingestions will be benign. Button batteries that lodge in the esophagus should be removed immediately by endoscopy. Other ingestions can be managed with observation at home unless symptoms develop. Weekly radiographic examinations should be done to follow the progression of the button battery in these patients. The expected threat of mercury toxicity has not materialized. Patients who ingest mercury-containing button batteries should undergo chelation therapy and monitoring of levels only if symptoms characteristic of mercury toxicity develop. Cathartics and water-soluble enemas, although not indicated for intact button batteries, may be useful in speeding transit of mercury if it is released into the bowel. Other metals present in button batteries appear to pose no health threat.     

A Dual-Input Neural Network for Online State-of-Charge Estimation of the Lithium-Ion Battery throughout Its Lifetime

Online state-of-charge (SOC) estimation for lithium-ion batteries is one of the most important tasks of the battery management system in ensuring its operation safety and reliability. Due to the advantages of learning the long-term dependencies in between the sequential data, recurrent neural networks (RNNs) have been developed and have shown their superiority over SOC estimation. However, only time-series measurements (e.g., voltage and current) are taken as inputs in these RNNs. Considering that the mapping relationship between the SOC and the time-series measurements evolves along with the battery degradation, there still remains a challenge for RNNs to estimate the SOC accurately throughout the battery’s lifetime. In this paper, a dual-input neural network combining gated recurring unit (GRU) layers and fully connected layers (acronymized as a DIGF network) is developed to overcome the above-mentioned challenge. Its most important characteristic is the adoption of the state of health (SOH) of the battery as the network input, in addition to time-series measurements. According to the experimental data from a batch of LiCoO₂ batteries, it is validated that the proposed DIGF network is capable of providing more accurate SOC estimations throughout the battery’s lifetime compared to the existing RNN counterparts. Moreover, it also shows greater robustness against different initial SOCs, making it more applicable for online SOC estimations in practical situations. Based on these verification results, it is concluded that the proposed DIGF network is feasible for estimating the battery’s SOC accurately throughout the battery’s lifetime against varying initial SOCs.     

Designing Spinel Li4Ti5O12 Electrode as Anode Material for Poly(ethylene)oxide-Based Solid-State Batteries

The development of a promising Li metal solid-state battery (SSB) is currently hindered by the instability of Li metal during electrodeposition; which is the main cause of dendrite growth and cell failure at elevated currents. The replacement of Li metal anode by spinel Li₄Ti₅O₁₂ (LTO) in SSBs would avoid such problems, endowing the battery with its excellent features such as long cycling performance, high safety and easy fabrication. In the present work, we provide an evaluation of the electrochemical properties of poly(ethylene)oxide (PEO)-based solid-state batteries using LTO as the active material. Electrode laminates have been developed and optimized using electronic conductive additives with different morphologies such as carbon black and multiwalled carbon nanotubes. The electrochemical performance of the electrodes was assessed on half-cells using a PEO-based solid electrolyte and a lithium metal anode. The optimized electrodes displayed an enhanced capability rate, delivering 150 mAh g⁻¹ at C/2, and a stable lifespan over 140 cycles at C/20 with a capacity retention of 83%. Moreover, postmortem characterization did not evidence any morphological degradation of the components after ageing, highlighting the long-cycling feature of the LTO electrodes. The present results bring out the opportunity to build high-performance solid-state batteries using LTO as anode material.     

Spark Plasma Sintering of LiFePO4: AC Field Suppressing Lithium Migration

Our work proposes a comparison between Spark Plasma Sintering of LiFePO₄ carried out using an Alternating Current (AC) and Direct Current (DC). It quantifies the Li-ion migration using DC, and it validates such hypothesis using impedance spectroscopy, X-ray photoelectron spectroscopy and inductively coupled plasma optical emission spectroscopy. The use of an AC field seems effective to inhibit undesired Li-ion migration and achieve high ionic conductivity as high as 4.5 × 10⁻³ S/cm, which exceeds by one order of magnitude samples processed under a DC field. These results anticipate the possibility of fabricating a high-performance all-solid-state Li-ion battery by preventing undesired Li loss during SPS processing.     

A Composite Porous Membrane Based on Derived Cellulose for Transient Gel Electrolyte in Transient Lithium-Ion Batteries

The transient lithium-ion battery is a potential candidate as an integrated energy storage unit in transient electronics. In this study, a mechanically robust, transient, and high-performance composite porous membrane for a transient gel electrolyte in transient lithium-ion batteries is studied and reported. By introducing a unique and controllable circular skeleton of methylcellulose to the carboxymethyl cellulose-based membrane, the elastic modulus and tensile strength of the composite porous membrane (CPM) are greatly improved, while maintaining its micropores structure and fast transiency. Results show that CPM with 5% methylcellulose has the best overall performance. The elastic modulus, tensile strength, porosity, and contact angle of the optimized CPM are 335.18 MPa, 9.73 MPa, 62.26%, and 21.22°, respectively. The water-triggered transient time for CPM is less than 20 min. The ionic conductivity and bulk resistance of the CPM gel electrolyte are 0.54 mS cm⁻¹ and 4.45 Ω, respectively. The obtained results suggest that this transient high-performance CPM has great potential applications as a transient power source in transient electronics.     

Symmetry Analysis of Magnetoelectric Effects in Perovskite-Based Multiferroics

In this article, we performed symmetry analysis of perovskite-based multiferroics: bismuth ferrite (BiFeO₃)-like, orthochromites (RCrO₃), and Ruddlesden–Popper perovskites (Ca₃Mn₂O₇-like), being the typical representatives of multiferroics of the trigonal, orthorhombic, and tetragonal crystal families, and we explored the effect of crystallographic distortions on magnetoelectric properties. We determined the principal order parameters for each of the considered structures and obtained their invariant combinations consistent with the particular symmetry. This approach allowed us to analyze the features of the magnetoelectric effect observed during structural phase transitions in Bi_xR_1−xFeO₃ compounds and to show that the rare-earth sublattice has an impact on the linear magnetoelectric effect allowed by the symmetry of the new structure. It was shown that the magnetoelectric properties of orthochromites are attributed to the couplings between the magnetic and electric dipole moments arising near Cr³⁺ ions due to distortions linked with rotations and deformations of the CrO₆ octahedra. For the first time, such a symmetry consideration was implemented in the analysis of the Ruddlesden–Popper structures, which demonstrates the possibility of realizing the magnetoelectric effect in the Ruddlesden–Popper phases containing magnetically active cations, and allows the estimation of the conditions required for its optimization.     

Safety of Implantable Pacemakers and Cardioverter Defibrillators in the Magnetic Field of a Novel Remote Magnetic Navigation System

Safety of Pacemakers and ICDs . Introduction: Electromagnetic interference with pacemaker and implantable cardioverter defibrillator (ICD) systems may cause temporary or permanent system malfunction of implanted devices. The aim of this study was to evaluate potential interference of a novel magnetic navigation system with implantable rhythm devices. Methods: A total of 121 devices (77 pacemakers, 44 ICDs) were exposed to an activated NIOBE II® Magnetic Navigation System (Stereotaxis, St. Louis, MO, USA) at the maximal magnetic field strength of 0.1 Tesla and evaluated in vitro with respect to changes in parameter settings of the device, changes of the battery status/detection of elective replacement indication, or alterations of data stored in the device. Results: A total of 115 out of 121 (95%) devices were free of changes in parameter settings, battery status, and internally stored data after repeated exposition to the electromagnetic field of the remote magnetic navigation system. Interference with the magnetic navigation field was observed in 6 pacemakers, resulting in reprogramming to a power‐on‐reset mode with or without detection of the elective replacement indication in 5 devices and abnormal variance of battery status in one device. All pacemakers could be reprogrammed to the initial modes and the battery status proved to be normal some minutes after the pacemakers had been removed from the magnetic field. Conclusion: Interference of a remote magnetic navigation system (at maximal field strength) with pacemakers and ICDs not connected to leads with antitachycardic detection and therapies turned off is rare. Occurring functional abnormalities could be reprogrammed in our sample. An in vitro study will give information about interference of devices connected to leads. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1136‐1141)     

Simultaneous Measurement of Magnetic Field and Temperature Utilizing Magnetofluid-Coated SMF-UHCF-SMF Fiber Structure

We have proposed and experimentally demonstrated a dual-parameter optical fiber sensor for simultaneous measurement of magnetic field and temperature. The sensor is a magnetofluid-coated single-mode fiber (SMF)-U-shaped hollow-core fiber (UHCF)-single-mode fiber (SMF) (SMF-UHCF-SMF) fiber structure. Combined with the intermodal interference and the macro-bending loss of the U-shaped fiber structure, the U-shaped fiber sensor with different bend diameters was investigated. In our experiments, the transmission spectra of the sensor varied with magnetic field strength and temperature around the sensing structure, respectively. The dip wavelengths of the interference spectra of the proposed sensor exhibit red shifts with magnetic field strength and temperature, and the maximum sensitivity of magnetic field strength and temperature were 1.0898 nm/mT and 0.324 nm/°C, respectively.     

Safety and Functional Integrity of Continuous Glucose Monitoring Components After Simulated Radiologic Procedures

Background:We investigated wearable components of the Dexcom G6 continuous glucose monitoring (CGM) System in simulated therapeutic and diagnostic radiologic procedures.Methods:G6 transmitters were loaded with simulated glucose data and attached to sensors. Sets of sensor/transmitter pairs were exposed to x-rays to simulate a radiotherapeutic procedure and to radiofrequency (RF) and magnetic fields to simulate diagnostic magnetic resonance imaging (MRI). The x-ray simulation provided a cumulative dose of 80 Gy. The MRI simulation used RF fields oscillating at 64 or 128 MHz and magnetic fields of 1.5 or 3 T. During the MRI simulation, displacement force, induced heating, and induced currents were measured. After the simulations, bench tests were used to assess data integrity on the transmitters and responsiveness of sensors to various concentrations of aqueous glucose.Results:Glucose concentrations reported by sensor/transmitter pairs after undergoing x-irradiation or a simulated MRI exam were similar to those from control (unexposed) devices. During the 3 T MRI simulation, the devices experienced a displacement force of 306 g, which was insufficient to dislodge the sensor/transmitter from the substrate, RF-induced heating of <2°C, and an induced current of <16 pA. Data stored on the transmitters prior to the MRI simulation remained intact.Conclusion:Wearable components of the G6 CGM System retain basic functionality and data integrity after exposure to simulated therapeutic and diagnostic radiologic procedures. The devices are unlikely to be affected by x-irradiation used in typical imaging studies. Simulated MRI procedures create displacement force, minimal heating, and current in sensor/transmitter pairs.     

Progress and Challenges in Industrially Promising Chemical Vapour Deposition Processes for the Synthesis of Large-Area Metal Oxide Electrode Materials Designed for Aqueous Battery Systems

The goal of the battery research community is to reach sustainable batteries with high performance, meaning energy and power densities close to the theoretical limits, excellent stability, high safety, and scalability to enable the large-scale production of batteries at a competitive cost. In that perspective, chemical vapour deposition processes, which can operate safely under high-volume conditions at relatively low cost, should allow aqueous batteries to become leading candidates for energy storage applications. Research interest and developments in aqueous battery technologies have significantly increased the last five years, including monovalent (Li⁺, Na⁺, K⁺) and multivalent systems (Mg²⁺, Zn²⁺, Al³⁺). However, their large-scale production is still somewhat inhibited, since it is not possible to get electrodes with robust properties that yield optimum performance of the electrodes per surface area. In this review paper, we present the progress and challenges in the growth of electrodes through chemical vapour deposition at atmospheric pressure, which is one procedure that is proven to be industrially competitive. As battery systems attract the attention of many researchers, this review article might help those who work on large-scale electrical energy storage.     

Synthesis and Electrochemical Performance of Graphene @ Halloysite Nanotubes/Sulfur Composites Cathode Materials for Lithium-Sulfur Batteries

Natural halloysite nanotubes (HNTs) and reduced graphene oxide (RGO) were introduced into the S cathode material to form HNTs/S and RGO@HNTs/S composite electrode to improve the electrochemical performance of Li-S batteries. The effect of acid etching temperature on the morphology and pore structure of HNTs was explored and the morphological characteristics and electrochemical performance of composite electrodes formed by HNTs that after treatment with different acid etching temperatures and RGO were compared. The result shows that the cycling stability and the utilization rate of active substances of the Li-S battery were greatly improved because the pore structure and surface polarity functional groups of HNTs and the introduction of RGO provide a conductive network for insulating sulfur particles. The RGO@HNTs treated by acid treatment at 80 °C (RGO@HNTs-80/S) composite electrode at 0.1 C has an initial capacity of 1134 mAh g⁻¹, the discharge capacity after 50 cycles retains 20.1% higher than the normal S electrode and maintains a specific discharge capacity of 556 mAh g⁻¹ at 1 C. Therefore, RGO and HNTs can effectively improve the initial discharge specific capacity, cycle performance and rate performance of Li-S batteries.     

The Positive Effect of ZnS in Waste Tire Carbon as Anode for Lithium-Ion Batteries

There is great demand for high-performance, low-cost electrode materials for anodes of lithium-ion batteries (LIBs). Herein, we report the recovery of carbon materials by treating waste tire rubber via a facile one-step carbonization process. Electrochemical studies revealed that the waste tire carbon anode had a higher reversible capacity than that of commercial graphite and shows the positive effect of ZnS in the waste tire carbon. When used as the anode for LIBs, waste tire carbon shows a high specific capacity of 510.6 mAh·g⁻¹ at 100 mA·g⁻¹ with almost 97% capacity retention after 100 cycles. Even at a high rate of 1 A·g⁻¹, the carbon electrode presents an excellent cyclic capability of 255.1 mAh·g⁻¹ after 3000 cycles. This high-performance carbon material has many potential applications in LIBs and provide an alternative avenue for the recycling of waste tires.     

Genuine divalent magnesium-ion storage and fast diffusion kinetics in metal oxides at room temperature

Rechargeable magnesium batteries represent a viable alternative to lithium-ion technology that can potentially overcome its safety, cost, and energy density limitations. Nevertheless, the development of a competitive room temperature magnesium battery has been hindered by the sluggish dissociation of electrolyte complexes and the low mobility of Mg²⁺ ions in solids, especially in metal oxides that are generally used in lithium-ion batteries. Herein, we introduce a generic proton-assisted method for the dissociation of the strong Mg–Cl bond to enable genuine Mg²⁺ intercalation into an oxide host lattice; meanwhile, the anisotropic Smoluchowski effect produced by titanium oxide lattices results in unusually fast Mg²⁺ diffusion kinetics along the atomic trough direction with a record high ion conductivity of 1.8 × 10⁻⁴ S ⋅ cm⁻¹ on the same order as polymer electrolyte. The realization of genuine Mg²⁺ storage and fast diffusion kinetics enabled a rare high-power Mg-intercalation battery with inorganic oxides. The success of this work provides important information on engineering surface and interlayer chemistries of layered materials to tackle the sluggish intercalation kinetics of multivalent ions.

Rechargeable multivalent metal-ion batteries are promising energy sources that can potentially satisfy the existing demand for high-energy density electrochemical energy storage devices (1, 2). The electrochemical discharge and charge reactions in these batteries involve multiple electron transfers per ion, which may significantly increase the ion storage capacity relative to that of monovalent batteries. Among the studied systems, Mg-ion batteries utilizing divalent magnesium ions (Mg²⁺) as charge carriers are considered the most viable option. In addition to their numerous advantages such as abundant Mg resources, low fabrication cost, and environmental friendliness, these batteries exhibit dendrite-free Mg plating and stripping during electrochemical cycling, which ensure high operational safety. Furthermore, the volumetric capacity of Mg anodes (3,833 mAh ⋅ cm⁻³) is almost twice as large as that of Li anodes (2,062 mAh ⋅ cm⁻³) (3–5). Unfortunately, it is very difficult to realize genuine storage and fast transport of Mg²⁺ ions in solids (especially in inorganic oxides) at low temperatures due to their high degree of polarization and charge density. The charge of the Mg²⁺ ion is two times larger than that of the Li⁺ ion, although the ionic radius of Mg²⁺ (0.72 Å) is close to that of Li⁺ (0.76 Å). As a result, Mg²⁺ ions are more likely to form strong covalent bonds with electrolytes (such as Mg–Cl bonds in the commonly used all-phenyl complex electrolytes) with very high dissociation energy. Meanwhile, the strong electrostatic interactions between Mg²⁺ ions and solid host lattices significantly inhibit their diffusion kinetics in these lattices. Resultantly, the migration barrier for Mg²⁺ ions is usually higher than that for Li⁺ ions in the same cathode material (6–8).To overcome the Mg bond dissociation barrier and enhance Mg-ion diffusion kinetics, intercalation chemistries based on solvated Mg²⁺ as the intercalating cation species, including Mg(DME)₃²⁺, Mg(H₂O)_x²⁺, and MgCl⁺, have been established (9–11). These complex ions lower the charge density by either increasing the ionic radius or decreasing the net charge. Although the storage of these complex ions alleviates the drawbacks related to the dissociation and diffusion of bare Mg²⁺ ions, it produces several challenges. The practical energy densities at the cell level for the hybrid battery based on such intercalation chemistry are lower than that of the battery exclusively involving Mg²⁺ storage. Additionally, the coinsertion of these bulky solvent molecules induces significant volume changes of the electrode, thereby limiting its cycle life. Recently, a two-pronged approach has been developed to overcome these challenges (12). It involved the storage of exclusively Mg²⁺ ions and their fast solid-state diffusion in an organic cathode fabricated from pyrene-4,5,9,10-tetraone. Heterogeneous enolization redox chemistry was utilized to avoid the bond cleavage and reformation; meanwhile, an electrolyte comprising weak-coordinated anions in an ethereal solvent blend was employed to increase the bulk ion mobility and promote Mg²⁺ desolvation on the electrode surface. However, it still remains a critical challenge in inorganic materials to overcome the two important problems: the ion dissociation in the conventional Mg chloride complex electrolyte and solid-state ion diffusion. The development of rechargeable inorganic cathodes for Mg batteries using a rational structural design is the major limiting factor of this promising post–Li-ion battery technology.Metal oxides are the most promising electrode materials for Li-ion batteries, taking advantage of their excellent chemical and thermal stabilities; however, this is not always true for Mg-ion batteries. Compared to sulfides and selenides, most metal oxides suffer from low reversible capacities and slow diffusion kinetics, owing to the higher strength of the Mg–O bond as compared with those of the Mg–S and Mg–Se bonds (7, 13). Furthermore, the reaction of Mg ions with highly polarizable O²⁻ ions often leads to MgO formation rather than Mg²⁺ intercalation, making it almost impossible to achieve reversibility in oxide-based cathodes (14). Therefore, the development of rechargeable metal-oxide electrode materials for Mg-ion batteries characterized by genuine Mg²⁺ storage, fast solid-state diffusion kinetics, and excellent cycling performance (especially at room and low temperatures) remained an unsurmountable challenge.In the present study, genuine Mg²⁺ intercalation/deintercalation and fast diffusion in oxide lattices were realized not only at room temperature but also at subzero temperatures. These outstanding results were achieved by placing protons on negatively charged metal-deficient oxide sheets and disorderly stacking these sheets over a certain distance (this strategy is schematically illustrated in Fig. 1). The stripping of Cl⁻ ions was facilitated by the presence of protons between the sheets, while fast Mg²⁺ diffusion was ensured by the extension of the wavefunction along an atomic trough on the unique sheet surface due to the anisotropic Smoluchowski effect. This induced the formation of flat potential-energy surfaces and diffusion highways, which gave a record high Mg-ion conductivity of 1.8 × 10⁻⁴ S ⋅ cm⁻¹. As a result, the fabricated Mg-ion cell exhibited a high-power density of 7.4 kW ⋅ kg⁻¹ while maintaining an energy of 113.0 Wh ⋅ kg⁻¹. Practically, the cell battery, which was charged in 55 s, could be gradually discharged for a stable long run of ∼4.5 h. Even at a subzero temperature of −15 °C, the electrode capacity remained above 55%, and the diffusion coefficient was in the range of 10⁻⁹ tο 10⁻¹¹ cm² ⋅ s⁻¹ (10⁻⁸ to 10⁻¹⁰ cm² ⋅ s⁻¹ at room temperature). The proposed strategy is generic and can be easily applied to other two-dimensional electrode materials, including titanium oxide, manganese oxide, and oxyanion-terminated titanium carbide.Open in a separate windowFig. 1.Schematic illustration. The genuine Mg²⁺ storage mechanism and fast diffusion in the oxide electrode, which were studied using PhMgCl–AlCl₃ electrolyte. The protons efficiently stripped Cl ions from the electrolyte complex, ensuring the genuine Mg²⁺-intercalation chemistry. The anisotropic Smoluchowski effect or wavefunction extension along the atomic troughs on the surface created pathways for the unusually fast diffusion of Mg²⁺ species.     

Effect of Surface Modification for Carbon Cathode Materials on Charge–Discharge Performance of Li-Air Batteries

Li-air batteries have attracted considerable attention as rechargeable secondary batteries with a high theoretical energy density of 11,400 kWh/g. However, the commercial application of Li-air batteries is hindered by issues such as low energy efficiency and a short lifetime (cycle numbers). To overcome these issues, it is important to select appropriate cathode materials that facilitate high battery performance. Carbon materials are expected to be ideal materials for cathodes due to their high electrical conductivity and porosity. The physicochemical properties of carbon materials are known to affect the performance of Li-air batteries because the redox reaction of oxygen, which is an important reaction for determining the performance of Li-air batteries, occurs on the carbon materials. In this study, we evaluated the effect of the surface modification of carbon cathode materials on the charge–discharge performance of Li-air batteries using commercial Ketjenblack (KB) and KB subjected to vacuum ultraviolet (VUV) irradiation as cathodes. The surface wettability of KB changed from hydrophobic to hydrophilic as a result of the VUV irradiation. The ratio of COOH and OH groups on the KB surface increased after VUV irradiation. Raman spectra demonstrated that no structural change in the KB before and after VUV irradiation was observed. The charge and discharge capacities of a Li-air battery using VUV-irradiated KB as the cathode decreased compared to original KB, whereas the cycling performance of the Li-air battery improved considerably. The sizes and shapes of the discharge products formed on the cathodes changed considerably due to the VUV irradiation. The difference in the cycling performance of the Li-air battery was discussed from the viewpoint of the chemical properties of KB and VUV-irradiated KB.     

Flexible Pressure Sensor with Micro-Structure Arrays Based on PDMS and PEDOT:PSS/PUD&CNTs Composite Film with 3D Printing

Flexible pressure sensors are widely used in different fields, especially in human motion, robot monitoring and medical treatment. Herein, a flexible pressure sensor consists of the flat top plate, and the microstructured bottom plate is developed. Both plates are made of polydimethylsiloxane (PDMS) by molding from the 3D printed template. The contact surfaces of the top and bottom plates are coated with a mixture of poly (3,4-ethylenedioxythiophene) poly (styrene sulfonate) (PEDOT:PSS) and polyurethane dispersion (PUD) as stretchable film electrodes with carbon nanotubes on the electrode surface. By employing 3D printing technology, using digital light processing (DLP), the fabrication of the sensor is low-cost and fast. The sensor models with different microstructures are first analyzed by the Finite Element Method (FEM), and then the models are fabricated and tested. The sensor with 5 × 5 hemispheres has a sensitivity of 3.54 × 10⁻³ S/kPa in the range of 0–22.2 kPa. The zero-temperature coefficient is −0.0064%FS/°C. The durability test is carried out for 2000 cycles, and it remains stable during the whole test. This work represents progress in flexible pressure sensing and demonstrates the advantages of 3D printing technology in sensor processing.     

On the Theory of Magnetoelectric Coupling in Fe2Mo3O8

In the last decade, Fe₂Mo₃O₈ was recognized for a giant magnetoelectric effect, the origin of which is still not clear. In the present paper, we contribute to the microscopic theory of the magnetoelectric coupling in this compound. Using crystal field theory and the molecular field approximation, we calculated the low-lying energy spectrum for iron ions and their interaction with electric and magnetic fields. Classical ionic contribution to the electric polarization related to the ionic shifts is also estimated. It is found that the electronic and ionic contributions to the electric polarization are comparable and these mechanisms support each other at T<TN. The suggested electronic mechanism provides insight into the nature of huge jumps in polarization upon phase transitions from paramagnetic (PM) to antiferromagnetic (AFM) and then to ferrimagnetic (FRM) states under an applied external magnetic field as well as the large differential magnetoelectric coefficient.     

Tensile Property and Corrosion Performance of Ag Microalloying of Al-Cu Alloys for Positive Electrode Current Collectors of Li-Ion Batteries

The development of a current collector for Li-ion batteries is of great significance for improving the performance of Li-ion batteries. Tensile property and corrosion performance of the positive electrode current collectors are an indispensable prerequisite for the realization of high-performance Li-ion batteries. In our study, the effects of Ag alloying on the microscopic structure, electrical conductivity, tensile property and corrosion resistance of Al-xCu (x = 0.1–0.15%) alloy foils were investigated. Moderate Ag addition on the Al-Cu alloy could reduce the size of second phases and promote the formation of second phases. The tensile strength of the Al-0.1Cu-0.1Ag alloy was higher than that of the Al-0.1Cu alloy at both room and high temperatures. All of the alloy foils demonstrated high electrical conductivity around 58% ICAS. The corrosion potential and corrosion current density of the Al-0.1Cu alloy were demonstrated by Tafel polarization to be −873 mV and 37.12 μA/cm², respectively. However, the Al-0.1Cu-0.1Ag alloy showed enhanced corrosion resistance after the Ag element was added to the Al-0.1Cu alloy, and the Al-0.1Cu-0.1Ag alloy had a greater positive corrosion potential of −721 mV and a lower corrosion current density of 1.52 μA/cm², which suggests that the Ag element could significantly improve the corrosion resistance of the Al-Cu alloy.     

Structural,Magnetic, Dielectric and Piezoelectric Properties of Multiferroic PbTi1−xFexO3−δ Ceramics

PbTi_1−xFe_xO_3−δ (x = 0, 0.3, 0.5, and 0.7) ceramics were prepared using the classical solid-state reaction method. The investigated system presented properties that were derived from composition, microstructure, and oxygen deficiency. The phase investigations indicated that all of the samples were well crystallized, and the formation of a cubic structure with small traces of impurities was promoted, in addition to a tetragonal structure, as Fe³⁺ concentration increased. The scanning electron microscopy (SEM) images for PbTi_1−xFe_xO_3−δ ceramics revealed microstructures that were inhomogeneous with an intergranular porosity. The dielectric permittivity increased systematically with Fe³⁺ concentration, increasing up to x = 0.7. A complex impedance analysis revealed the presence of multiple semicircles in the spectra, demonstrating a local electrical inhomogeneity due the different microstructures and amounts of oxygen vacancies distributed within the sample. The increase of the substitution with Fe³⁺ ions onto Ti⁴⁺ sites led to the improvement of the magnetic properties due to the gradual increase in the interactions between Fe³⁺ ions, which were mediated by the presence of oxygen vacancies. The PbTi_1−xFe_xO_3−δ became a multifunctional system with reasonable dielectric, piezoelectric, and magnetic characteristics, making it suitable for application in magnetoelectric devices.