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Since the 2000s, diseases that tend to occur in high-age groups such as degenerative arthritis and intervertebral disk has been gradually increasing in low-age groups due to incorrect gait or bad habits. One of the fundamental problems with these results can be found in an indifference to gait. This study aimed at determining the walking styles through pressure sensor. It uses a three-axis accelerometer and a gyro sensor to identify pigeon-toed walking and splay-footed walking. The system can monitor gait using the sensor data stored in the PC and smartphone applications transferred via Bluetooth. This can be visually confirmed through color changes in accordance with the sensor value with the neo-pixels. Research developments can analyze the type of gait as compared to the value for the case of incorrect gait based on normal pace with the acceleration value through the sensor. Through the experiment, the recognition rate capable of distinguishing in toeing gait was 56.25%, and out toeing gait was 81.25%. The system of this paper continuously collects gait data to enable monitoring whenever and wherever users want. It is easy to check when and where users walked with a normal gait or abnormal gait, and it is expected to help users manage their gait. This system may be approached as a precautionary measure by notifying other parts of the body that there is an abnormality in asymmetric walking (walking with differences in speed, angle, and stride of both feet) or when dragging feet.

Global Navigation Satellite System (GNSS) use the internal continuous reference times to evaluate a navigation solution, which includes U.S. GPS time, Russian GLONASS Time, the E.U. Galileo System Time, and Chinese Beidou time. GNSSs time are designed and configured to internally synchronize systems and evaluate navigation solution, and they are adjusted to synchronize their time into an external and stable reference clock. This paper analyzes and extracts requirements that are needed for designing components and design a component specification, which is based on the extracted components. From this study, common functions of GPS applications were constructed as a component. This method has advantages that can be assembled and reused. That is, it would develop a highly reliable method for software when common components are extracted from requirements for GNSS construction and component-based GNSS development process is achieved.

Blockchain-based digital forensics technology is an efficient way to prevent forgery/modulation of evidence including collecting and analyzing evidential data using the technology in compliance with smartphone forensics procedures after a smartphone is seized. Moreover, the use of large-capacity storage devices and various digital devices have become a realistic solution for its development of IT in situations where the existing digital forensics analysis methods are regarded as limitations. This paper analyzed user’s status on smartphone application and implemented a smartphone user analysis framework that may extract significant digital evidence in a digital forensic way based on a blockchain perspective. In this paper researched a system that may provide important information to digital forensic analysts through these frameworks. It is expected that the proposed system will be expanded by much more structured data and online unstructured data such as SNS reports.

A microgrid-patterned silicon (MPS) electrode is presented as an electroactive Li host, which enables stepwise sequential Si lithiation/delithiation and Li plating/stripping reactions for a high-energy-density Li–metal full cell.

A biphasic liquid electrolyte based on the kosmotropic effect is presented to fulfill the requirements of anodes and cathodes. Kosmotropic anions enable demixing of aqueous and nonaqueous electrolytes, improving redox kinetics at cathodes and Zn2+ cyclability at anodes.

The current lithium-ion battery (LIB) electrode fabrication process relies heavily on the wet coating process, which uses the environmentally harmful and toxic N-methyl-2-pyrrolidone (NMP) solvent. In addition to being unsustainable, the use of this expensive organic solvent substantially increases the cost of battery production, as it needs to be dried and recycled throughout the manufacturing process. Herein, we report an industrially viable and sustainable dry press-coating process that uses the combination of multiwalled carbon nanotubes (MWNTs) and polyvinylidene fluoride (PVDF) as a dry powder composite and etched Al foil as a current collector. Notably, the mechanical strength and performance of the fabricated LiNi0.7Co0.1Mn0.2O2 (NCM712) dry press-coated electrodes (DPCEs) far exceed those of conventional slurry-coated electrodes (SCEs) and give rise to high loading (100 mg cm−2, 17.6 mAh cm−2) with impressive specific energy and volumetric energy density of 360 Wh kg−1 and 701 Wh L−1, respectively.

Rechargeable calcium batteries have attracted increasing attention as promising multivalent ion battery systems due to the high abundance of calcium. However, the development has been hampered by the lack of suitable cathodes to accommodate the large and divalent Ca2+ ions at a high redox potential with sufficiently fast ionic conduction. Herein, we report a new intercalation host which presents 500 cycles with a capacity retention of 90% and a remarkable power capability at ~3.2 V (vs. Ca/Ca2+) in a calcium battery. The cathode material derived from Na0.5VPO4.8F0.7 is demonstrated to reversibly accommodate a large amount of Ca2+ ions, forming a series of CaxNa0.5VPO4.8F0.7 (0, Rechargeable calcium batteries are promising multivalent battery systems but the lack of suitable electrodes hampers their development. Here the authors report a cathode derived from polyanion framework that demonstrates uncommonly stable and fast intercalation behaviours of calcium ions.

Enabling reliable operation of energy storage devices over a wide temperature range without safety failures is an urgent prerequisite for extending their applications. Conventional liquid electrolytes in energy storage devices fail to reach this goal due to their limitations in freezing/boiling temperatures and flammability (for organic electrolytes). Here, we demonstrate a new class of aqueous eutectic electrolyte (AEE) based on a colligative property of lithium bis(trifluoromethane sulfonyl)imide (LiTFSI)-water binary mixture. The AEE (5.2 m LiTFSI in water) maximizes effect of freezing-point depression (below −40°C) and shows good electrochemical stability with electrode materials. We identify that a key-underlying mechanism of AEE is coordination of water molecules with Li+ and TFSI-. To explore potential use of AEE, we choose lithium-ion hybrid supercapacitors (HSC) as a model system. The AEE enables the HSC to provide exceptional high-rate cell performance over broad temperature ranges (−40°C ~ 100°C) without incurring fire or explosion.

It has been stated that bronchial anthracofibrosis (BAF) has an important relationship with pulmonary tuberculosis (TB), and the coexistence of TB and BAF is high. The purpose of this study was to compare the differences in computed tomography (CT) characteristics of pulmonary TB according to the presence of underlying BAF. Total of 202 consecutive patients who were diagnosed with pulmonary TB and underwent bronchoscopy and CT in our institution were retrospectively reviewed. We classified the patients into two groups according to the presence of BAF and compared the clinicoradiological findings between the two groups (anthracofibrosis group vs. nonanthracofibrosis group). Elderly and female patients were significantly higher in anthracofibrosis group (mean age 79 ± 7 (64–94) vs. 56 ± 17 (16–95), p < 0.001; female 89% vs. 29%, p < 0.001). The frequency of internal low-density area or focal contour bulge within atelectasis (64% vs. 1%, p < 0.001), lower lobe predominance (43% vs. 9%, p < 0.001), endobronchial involvement (46% vs. 15%, p < 0.001), and lymphadenopathy (57% vs. 28%, p = 0.002) were significantly higher in anthracofibrosis group. In contrast, the anthracofibrosis group showed lower frequency of upper lobe predominance (32% vs. 81%, p < 0.001) and cavitation (14% vs. 51%, p = 0.001). In conclusion, being aware of these atypical manifestations of pulmonary TB in the presence of BAF will be of great help in early detection of TB.

Despite the ever-increasing demand for transparent power sources in wireless optoelectronics, most of them have still relied on synthetic chemicals, thus limiting their versatile applications. Here, a class of transparent nanocellulose paper microsupercapacitors (TNP-MSCs) as a beyond-synthetic-material strategy is demonstrated. Onto semi-interpenetrating polymer network-structured, thiol-modified transparent nanocellulose paper, a thin layer of silver nanowire and a conducting polymer (chosen as a pseudocapacitive electrode material) are consecutively introduced through microscale-patterned masks (which are fabricated by electrohydrodynamic jet printing) to produce a transparent conductive electrode (TNP-TCE) with planar interdigitated structure. This TNP-TCE, in combination with solid-state gel electrolytes, enables on-demand (in-series/in-parallel) cell configurations in a single body of TNP-MSC. Driven by this structural uniqueness and scalable microfabrication, the TNP-MSC exhibits improvements in optical transparency (T = 85%), areal capacitance (0.24 mF cm

Single-ion conductors have garnered attention in energy storage systems as a promising alternative to currently widespread electrolytes that allow migration of cations and anions. However, ion transport phenomena of most single-ion conductors are affected by strong ion (e.g., Li + )–ion (immobilized anionic domains) interactions and tortuous paths, which pose an obstacle to achieving performance breakthroughs. Here, we present a Li + -centered G-quadruplex (LiGQ) as a class of single-ion conductor based on directional Li + slippage at the microscopic level. A guanine derivative with liquid crystalline moieties is self-assembled to form a hexagonal ordered columnar structure in the LiGQ, thereby yielding one-dimensional central channels that provide weak ion-dipole interaction and straightforward ionic pathways. The LiGQ exhibits weak Li + binding energy and low activation energy for ion conduction, verifying its viability as a new electrolyte design.

Single-ion conductors have garnered attention in energy storage systems as a promising alternative to currently widespread electrolytes that allow migration of cations and anions. However, ion transport phenomena of most single-ion conductors are affected by strong ion (e.g., Li

The upcoming ubiquitous electronics era, which will find widespread popularity of flexible/wearable electronics, self-powered devices, and the Internet of Things (IoT), stimulates us to develop a new concept of advanced power sources beyond currently available battery technologies. Among several approaches to reach this goal, printed power sources with various form factors and flexibility have recently garnered considerable attention as a promising system. The form factor-free, printed power sources, driven by their design diversity, shape/performance compatibility with electronics, and scalable/low-cost processability, enable monolithic/seamless integration with complex/unconventional-shaped electronic devices, in comparison to conventional rigid/bulky counterparts. Here, we review the current status and challenges of the form factor-free, printed power sources, with a focus on their materials development. Various printing techniques and their process parameters exploited for the printed power sources are briefly described. Subsequently, ink materials and chemistry of major cell components are discussed. Based on the understanding of the printing techniques and materials, applications of the printed power sources are overviewed to highlight their exceptional shape aesthetics and electrochemical characteristics in the integrated electronics. Finally, we propose development directions and outlook of the form factor-free, printed power sources as a device-customized energy storage system, along with prospects of their future applications.

In many catalyst systems, including fuel cell applications, control of the catalyst surface composition is important for improving activity since catalytic reactions occur only at the surface. However, it is very difficult to modify the surface composition without changing the morphology of metal nanoparticles. Herein, carbon-supported Pd3Au1 nanoparticles with uniform size and distribution are fabricated by tert-butylamine reduction method. Pd or Au surface segregation is induced by simply heating as-prepared Pd3Au1 nanoparticles under CO or Ar atmosphere, respectively. Especially, CO-induced Pd surface segregation allows the alloy nanoparticles to have a Pd-rich surface, which is attributed to the strong CO binding energy of Pd. To demonstrate the change in surface composition of Pd3Au1 alloy catalyst with the annealing gas species, the oxygen reduction reaction performance is investigated and consequently, Pd3Au1 catalyst with the highest number of surface Pd atoms indicates excellent catalytic activity. Therefore, the present work provides insights into the development of metal-based alloys with optimum structures and surface compositions for various catalytic systems.

We studied homogeneity in the microwave surface resistance of Au-coated YBa2Cu3O7−δ (Au/YBCO) films. The Au/YBCO film with 4-inches in diameter was prepared in-situ with the thicknesses of 68 nm and 365 nm for the Au layer and the YBa2Cu3O7−δ (YBCO) layer, respectively. We measured the effective surface resistance (RS,eff) of the Au/YBCO film at temperatures of 25 K, 60 K, 70 K, and 77 K, respectively, at 29 different positions on the film. The RS,eff values were analyzed with the finite thicknesses of the Au and the YBCO layers taken into consideration. The local RS,eff values of the Au/YBCO film appeared to be almost uniform at 25 K. Meanwhile significant positional dependences were observed for the RS,eff of the Au/YBCO film at 60 K, 70 K and 77 K, respectively, which seemed to be due to non-uniform local penetration depth (λ) of the YBCO layer rather than due to variations in the local real-part conductivity of the YBCO layer. The observed results could not be attributed to the properties of the Au layer. At temperatures below the critical temperature of YBCO, the observed RS,eff values of the Au/YBCO film were significantly lower than those estimated using the surface resistance of Au and YBCO, which reflected proximity effects of the normal-metal Au layer in contact with the superconducting YBCO layer. Homogeneity in the RS,eff of the Au/YBCO film might be correlated with the distributions in the local λ of the YBCO layer, providing valuable information needed for designing microwave filters.

Lithium metal batteries have higher theoretical energy than their Li-ion counterparts, where graphite is used at the anode. However, one of the main stumbling blocks in developing practical Li metal batteries is the lack of cathodes with high-mass-loading capable of delivering highly reversible redox reactions. To overcome this issue, here we report an electrode structure that incorporates a UV-cured non-aqueous gel electrolyte and a cathode where the LiNi0.8Co0.1Mn0.1O2 active material is contained in an electron-conductive matrix produced via simultaneous electrospinning and electrospraying. This peculiar structure prevents the solvent-drying-triggered non-uniform distribution of electrode components and shortens the time for cell aging while improving the overall redox homogeneity. Moreover, the electron-conductive matrix eliminates the use of the metal current collector. When a cathode with a mass loading of 60 mg cm−2 is coupled with a 100 µm thick Li metal electrode using additional non-aqueous fluorinated electrolyte solution in lab-scale pouch cell configuration, a specific energy and energy density of 321 Wh kg−1 and 772 Wh L−1 (based on the total mass of the cell), respectively, can be delivered in the initial cycle at 0.1 C (i.e., 1.2 mA cm−2) and 25 °C.

Fused aromatic networks (FANs) have been studied in efforts to overcome the low physicochemical stability of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), while preserving crystallinity. Herein, we describe the synthesis of a highly stable and crystalline FAN (denoted as Pz-FAN) using pyrazine-based building blocks to form porphyrazine (Pz) linkages via an irreversible reaction. Unlike most COFs and FANs, which are synthesized from two different building blocks, the new Pz-FAN is formed using a single building block by self-cyclotetramerization. Controlled and optimized reaction conditions result in a highly crystalline Pz-FAN with physicochemical stability. The newly prepared Pz-FAN displayed a high magnitude (1.16×10

Inspired by the atomic-sized, shape-regulated features of G-quadruplexes comprising guanine motifs with a monovalent metal cation, the G-quadruplex-forming ability, and properties of a guanine-based π-conjugated Y2 molecule containing bithiophene and peripheral dodecyl chain units in the presence of various cation salts (Li

Lithium-sulfur batteries are afflicted with capacity fading on account of polysulfide shuttling. A novel cost-effective electrode that can hinder the polysulfide shuttling and realize high active material utilization is highly required. Here, we demonstrate a flexible, electrically conductive, nanostructured, and asymmetric hybrid cathode by integrating a high-aspect-ratio wood nanocellulose and a low-cost commercial carbon nanotube (∼$ 0.2 g

Summary The forthcoming smart and ubiquitous electronics era presents significant interest in wireless interconnectivity and shape aesthetics. To fulfill this demand, a new class of advanced power sources with various form factors that are different from existing commercial ones is needed. Printed power sources have recently garnered substantial attention because of their design diversity, shape and performance compatibility with electronics, and scalable and low-cost processability. They are fabricated directly on complex-structured objects via application-customized printing techniques, enabling monolithic integration and electrochemical coupling with target devices. In this Perspective, we describe the current status and challenges of printed power sources, focusing on their role as built-in power sources. Various printing techniques and ink materials and chemistry of electrodes and electrolytes are discussed as key enabling factors. Noteworthy progress in printed built-in power sources is reviewed to highlight their design diversity and electrochemical superiority. Finally, development direction and outlook of printed built-in power sources are discussed in conjunction with their application fields.

In comparison with well-protected rigid batteries with liquid electrolytes, solid-state batteries (ssBs) are more beneficial, offering high flexibility, high wearability and leakage prevention. Currently, ssBs with the capability of bending and twisting have been extensively studied. However, it remains a challenge to develop a highly stretchable ssB with the maintenance of high performance. Herein, we report a stable solid-state zinc ion battery (ssZIB) based on a cellulose nanofiber (CNF)–polyacrylamide (PAM) hydrogel electrolyte and a Mg0.23V2O5·1.0H2O cathode. The designed CNF–PAM hydrogel shows high stretchability and robust mechanical stability. Moreover, the porous CNF–PAM hydrogel electrolyte provides efficient pathways for the transportation of zinc ions. And the robust layered structure of V2O5·1.0H2O pillared with Mg2+ ions and water supports the fast insertion/extraction of zinc ions in the lattice. Therefore, the designed ssZIB shows unprecedented high capacity at high current with durable cycling life. At a current density of 5 A g−1 (charging time of around 3 minutes), the ssZIBs can deliver a high reversible capacity of 216 mA h g−1 after 2000 cycles and retain 98.6% of the initial capacity, showing a high capacity and long-life durability at high currents. Furthermore, the designed spring ssZIBs can work under stretching with the strain reaching 650%. And the designed ssZIBs are still operational even under repeated bending, freezing, and heating conditions. The ssZIBs show robust mechanical stability, high stretchability and impressive electrochemical performance, providing a potential pathway to expand the application of ZIBs to a broad range of practical energy storage devices.

Coupling solar cells with energy storage devices promises to overcome issues associated with intermittency and longevity of the individual systems. Despite such significance of the coupled power sources, most previous approaches have involved bulky configurations with inactive components, eventually hindering their application as portable power sources. Furthermore, to enable practical/versatile applications of the coupled power sources, their operating voltages should be widened and customized for a specific purpose. Here, we demonstrate voltage-tunable portable power supplies based on tailored integration of interdigitated-back-contact-structured crystalline-silicon photovoltaics (cSiPV) and printed bipolar quasi-solid-state lithium-ion batteries (bQSSBs). The maximum power voltages of the cSiPVs and end-of-charge voltages of the bQSSBs are respectively varied and mutually matched to widen the operating voltage window (2.7–13.5 V) of cSiPV–bQSSB. The resulting cSiPV–bQSSB achieves high overall efficiency (10.2%) and stable photo-rechargeable cyclability. Moreover, cSiPV–bQSSB featuring a customized operating voltage is seamlessly unitized with various electronic devices and exhibits sustainable long-time operation under variable weather conditions.

Lithium metal is regarded as the “Holy Grail” for rechargeable batteries yet it still suffers from low coulombic efficiency caused by its high reactivity toward the electrolyte. The so-formed solid-electrolyte interphases (SEIs) are ununiform and sluggish-ion-conducting further inducing severe dendrite growth. Herein, we report the in situ LiF-embedded covalent organic framework (COF) as a novel artificial lithium/electrolyte interphase. Briefly, an electrochemically active COF ultrathin film is synthesized by interfacial aldimine condensation, in which lithiophilic moieties reside in the high-surface-area COF film and can locally concentrate Li-salts from a dilute electrolyte. This promotes the electrochemical in situ formation of anion-derived LiF-rich SEI during the first cycling. Owing to the coaxially orientated microporous channels displayed in the COF, the as-formed LiF grains are confined in the micropores and evenly distributed throughout the COF matrix, thereby enhancing the mechanical strength of the SEI against dendrite growth as well as retaining flexibility to tolerate the anode volume change over cycling. Also, the Li+ diffusion pathway is highly ordered along the 1D pore walls of the COF so as to spatially homogenize Li+ flux. Therefore, the LiF-embedded COF interphase exhibits cooperative effectiveness to greatly stabilize the lithium metal anode. The full cell maintains its excellent performances with stable cycling and high efficiency in the close-to-practice conditions.

The battery separator is an essential component of batteries that strongly affects their performance. The control of their properties being particularly important for obtaining lithium-ion batteries with high cycling performance. Separators are placed between both electrodes, should show high ionic conductivity, excellent mechanical and thermal stability and can be divided into six main types: microporous membranes, nonwoven membranes, electrospun membranes, membranes with external surface modification, composite membranes and polymer blends. Considering the relevance of battery separators in the performance of lithium-ion batteries, this work provides the recent advances and an analysis of the main properties of the different types of separators. Despite the large efforts on this area, it is still necessary to improve their characteristics based on new materials developments for this battery component. This paper also summarizes the recent advances in different solid electrolytes based on polymer and ceramic materials for a transition from conventional batteries to solid state batteries, that will allow the next generation of high-performance, safer and sustainable batteries. Finally, the main research and development directions and future trends in the area of separator membranes for lithium-ion batteries are presented.