Portable Electronic Devices Research Articles

Analysis of Lithium-ion Batteries through Electrochemical Impedance Spectroscopy Modeling

Electrochemical impedance spectroscopy (EIS) is a very effective methodology employed in the evaluation of performance and degradation mechanisms associated with lithium-ion batteries. In order to comprehend the complex electrochemical processes taking place within these energy storage devices, reliable and effective diagnostic tools are required due to the constant improvements in battery technology. EIS methodology has gained prominence as a very effective non-destructive method for examining the electrochemical characteristics of batteries. This technique offers significant contributions by providing useful insights into the internal operations of batteries. The main objective of this study is to create an electrical equivalent circuit model of a lithium-ion battery based on physics, and then use EIS to comprehend the electrical behavior and impedance of the battery to evaluate its performance under various operating scenarios. We seek to identify the critical elements influencing the battery’s capacity, performance, and lifespan by capturing the intricate interaction of EIS. The results of this research are going to enhance the understanding of battery behavior and supporting the design as a more reliable and efficient energy storage systems for a wide range of applications, from portable electronic devices to electric vehicles and renewable energy integration.

Interfacial toughening for high-efficiency perovskite solar modules

The distinctive benefits of perovskite solar cells, such as their lightweight nature, high flexibility, and ease of deformation, have garnered significant interest. These characteristics make them well-suited for use in portable electronic devices. Nevertheless, a large efficiency gap still exists between laboratory-based small cells and industrial-oriented large-scale modules. One of the primary reasons for the efficiency losses is the limited adhesion at the brittle interface between the perovskite layer and hole transport layer. Herein, potassium acetate is selected to tailor the interface of perovskite/hole transport layer. The presence of potassium acetate between the perovskite layer and hole transport layer has the potential to enhance the p-type perovskite interface. The strengthening of the interface contact could be verified by the utilization of KPFM and DFT calculations. As a result, the charge separation is accelerated associated with the substantial enhancement in Voc from 1.118 V to 1.139 V and the power conversion efficiency of the solar cell has been enhanced, resulting in an increase from 23.76% to 24.81%. Additionally, the perovskite solar module exhibits little loss, with an efficiency of 21.13% with an aperture area of 29.0 cm2.

Lightweight thermoplastic polyurethane/multi-wall carbon nanotube foams with a continuous gradient cell structure for electromagnetic interference shielding

With the rapid development of portable microelectronic devices, materials with tunable electromagnetic shielding (EMI) performance and comfort of use have become urgently necessary. A lightweight, conductive thermoplastic polyurethane/multi-walled carbon nanotube (TPU/MWCNT) composite foam with a continuous gradient cell structure has been developed to impede electromagnetic wave reflection induced by excessive impedance mismatch. The continuous gradient distribution of cell structure and conductivity provides the TPU/MWCNT composite foams with distinct shielding effects of electromagnetic waves in both front and back gradient directions. The maximum front absorption coefficient (A) reached 0.93, which is higher than any foam with a uniform cell size within the cell size range of the gradient composite foams. At the same time, the gradient composite foams possess the characteristics of lightweight, high elasticity, and extensibility. The weight was decreased by 67.27–85.45 %, the elastic recovery ratio of compression reached 95 %, and the toughness was also excellent. Numerical simulation of the gradient foam model was conducted using CST Microwave Studio to uncover the gradient asymptotic dissipation mechanisms. The lightweight and stretchable continuous gradient foams show great promises for the next-generation portable electronic devices that generate no radiation pollution.

A Programmable Ambient Light Sensor with Dark Current Compensation and Wide Dynamic Range.

Ambient light sensors are becoming increasingly popular due to their effectiveness in extending the battery life of portable electronic devices. However, conventional ambient light sensors are large in area and small in dynamic range, and they do not take into account the effects caused due to a dark current. To address the above problems, a programmable ambient light sensor with dark current compensation and a wide dynamic range is proposed in this paper. The proposed ambient light sensor exhibits a low current power consumption of only 7.7 µA in dark environments, and it operates across a wide voltage range (2-5 V) and temperature range (-40-80 °C). It senses ambient light and provides an output current proportional to the ambient light intensity, with built-in dark current compensation to effectively suppress the effects of a dark current. It provides a wide dynamic range over the entire operating temperature range with three selectable output-current gain modes. The proposed ambient light sensor was designed and fabricated using a 0.18 µm standard CMOS process, and the effective area of the chip is 663 µm × 652 µm. The effectiveness of the circuit was verified through testing, making it highly suitable for portable electronic products and fluorescent fiber-optic temperature sensors.

Unraveling the relationship between the mineralogical characteristics and lithium storage performance of natural graphite anode materials

Anode materials play critical role in cycling life of lithium-ion batteries in practical applications such as electric vehicles (EVs), portable electronic devices, and large-scale power grids. Natural graphite is one of the most successful anodes for commercial lithium-ion batteries due to its high theoretical capacity and low cost and low operating voltage. The mineralogical properties of graphite minerals have an important effect on the electrochemical performance of graphite anode, while their relationship remains ambiguous. In this work, natural graphite samples from four main graphite mining areas in China were selected as the research object, and their mineralogical characteristics were characterized by XRD, SEM, Raman, ICP, SEM, FIB, BET and other test methods. The properties of crystallinity, morphology, surface/phase defects, impurities, and specific surface area of graphite were studied. The results show that the cyclic stability of graphite is mainly affected by bulk defects and crystallinity, and the initial coulombic efficiency is mainly affected by surface defects and specific surface area. Graphite samples with appropriate surface defects, fewer volume defects, appropriate crystallinity, and small specific surface area have better electrochemical performance. It is hoped that this work should guide the manufacture and modification of the natural graphite anodes and promote its wider application in lithium-ion batteries.

A greater modulation of the visual and fronto-parietal networks for children in a post-media versus pre-media exposure group.

Media use in children has exploded in the past several decades, most recently fuelled by portable electronic devices. This study aims to explore differences in functional brain connectivity in children during a story-listening functional MRI (fMRI) task using data collected before (1998) and after (2013) the widespread adoption of media. Cross-sectional data were collected from English-speaking 5- to 7-year-old children at Cincinnati Children's Hospital Medical Center, USA, of a functional MRI narrative comprehension task completed in 1998 (n = 22) or 2013 (n = 25). Imaging data were processed using a graph theory approach, focusing on executive functions, language and visual processing networks supporting reading. Group differences suggest more efficient processing in the fronto-parietal network in the pre-media group while listening to stories. A modulation of the visual and fronto-parietal networks for the post-media exposure group was found. Further studies are needed to assess effects over time in the more exposed group to discern a causal effect of portable devices on cognitive networks.

Investigation of the Single-Particle Scale Structure-Activity Relationship Providing New Insights for the Development of High-Performance Batteries.

As electric vehicles, portable electronic devices, and tools have increasingly high requirements for battery energy density and power density, constantly improving battery performance is a research focus. Accurate measurement of the structure-activity relationship of active materials is key to advancing the research of high-performance batteries. However, conventional performance tests of active materials are based on the electrochemical measurement of porous composite electrodes containing active materials, polymer binders, and conductive carbon additives, which cannot establish an accurate structure-activity relationship with the physical characterization of microregions. In this review, in order to promote the accurate measurement and understanding of the structure-activity relationship of materials, the electrochemical measurement and physical characterization of energy storage materials at single-particle scale are reviewed. The potential problems and possible improvement schemes of the single particle electrochemical measurement and physical characterization are proposed. Their potential applications in single particle electrochemical simulation and machine learning are prospected. This review aims to promote the further application of single particle electrochemical measurement and physical characterization in energy storage materials, hoping to achieve 3D unified evaluation of physical characterization, electrochemical measurement, and theoretical simulation at the single particle scale to provide new inspiration for the development of high-performance batteries.

Multifunctional electronic skins for ultra-sensitive strain, temperature, humidity sensing, and energy harvesting

Though gaining increasing attention in various portable and wireless electronic devices and sensors, flexible gels used in strain sensors and triboelectric nanogenerators (TENGs) still suffer from inferior mechanical properties and lack long-term stability. Herein, multifunctional electronic skins (e-skin) from oriented 2D nanosheets enhanced eutectogel were facilely fabricated via a one-step curing strategy with excellent transparency (96%), superb elasticity (1613%), toughness (17.22 MPa). Moreover, the multifunctional e-skin also exhibits temperature and humidity sensibility. Notably, the as-assembled TENG e-skin exhibits high and stable electrical output performances, including an open-circuit voltage of 224 V, short-circuit current of 7.1 μA, and short-circuit charge of 640 nC. Meanwhile, the TENG can easily light up 130 LEDs, charge capacitors to drive a calculator, and sustain a long service life (120 days). Furthermore, it can serve as a self-powered biomechanical sensor to realize the real-time monitoring of various human motions, showing application potentials in wearable electronics, human health management, and energy harvesting systems.

Enhanced thermal stability and power factor in layered Bi2Se0.5Te2.5 Thin films across a broad temperature range

Bi2Te3-based n-type thin films with high thermoelectric performances are typically synthesised through the formation of dense structures, a process conventionally conducted at high temperatures. However, this method compromises thermal stability. In this study, structural design and multiple-step annealing were employed to enhance the thermal stability of high-performance Bi2Se0.5Te2.5 thin films. Post-annealing, the disparity in the values of the Seebeck coefficient over the entire test temperature range, was reduced to 20 μV K−1, which is approximately 32 % compared to pre-annealing measurements. The layered Bi2Se0.5Te2.5 thin film demonstrated an elevated power factor (28 × 10−4 W m−1K−2), which was maintained across a broad temperature spectrum. This multiple-step annealing approach not only refines the structural integrity by extending the atomic diffusion duration but also mitigates defects and augments compositional uniformity at reduced temperatures. Consequently, layered Bi2Se0.5Te2.5 films emerge as promising candidates for thermoelectric materials, offering enhanced long-term stability for diverse applications, including electric and hybrid electric vehicles, and portable electronic devices.

A PVDF/MWCNTs/GO@MWCNTs/AgNWs bilayer structured composite film with ultra‐high EMI shielding and conductivity performance

AbstractElectromagnetic interference (EMI) shielding materials with easy processing, high electrical conductivity, and excellent absorption loss are urgently needed in aerospace, military stealth and portable electronic devices. In this study, a polyvinylidene fluoride/multi‐walled carbon nanotubes (PVDF/MWCNTs)‐3 wt% composite film prepared by simple solution mixing and polyethylene terephthalate (PET) nonwoven scraping method was used as the substrate, and the PVDF/MWCNTs/graphene oxide@multi‐walled carbon nanotubes (PVDF/MWCNTs/GO@MWCNTs) and PVDF/MWCNTs/GO@MWCNTs/silver nanowires (PVDF/MWCNTs/GO@MWCNTs/AgNWs) bilayer composite films were prepared by vacuum‐assisted filtration (VAF). When the amount of GO@MWCNTs was 20 mL, the conductivity of PVDF/MWCNTs/GO@MWCNTs film is 3.5 × 101 S m−1, the total EMI shielding effectiveness (EMI SET) was 15.5 dB and the EMI absorption efficiency (EMI SEA) was 10.7 dB, the specific EMI SE (SSE/T) was 539.5 dB/ dB/(cm−2 g). When the amount of AgNWs was 25 mL, the conductivity of PVDF/MWCNTs/GO@MWCNTs/AgNWs film with 0.47 mm thickness was 1.6 × 104 S m−1, the EMI SET was 69.1 dB, the EMI SEA was 61.1 dB, and the SSE/T was 2320.0 dB cm2 g−1. The results show that the absorption was played a dominant role in the EMI shielding mechanism of obtained films. The addition of GO@MWCNTs/AgNWs increases the electrical conductivity and EMI shielding performance of the film more than the addition of GO@MWCNTs. This is mainly because GO， MWCNTs and AgNWs formed a novel three‐dimensional conductive network structure inside the composite film due to their hydrogen bonding and van der Waals forces, which increases the carrier channels and promotes the interaction between the internal microcurrents and the electromagnetic waves, achieving the purpose of attenuating the electromagnetic waves. The obtained PVDF/MWCNTs/GO@MWCNTs/AgNWs film has good potential in EMI shielding in aerospace, military and electronic intelligence applications.Highlights Well‐dispersed and highly conductive GO@MWCNTs were prepared by hydrothermal synthesis. AgNWs with good conductivity and high aspect ratio were prepared. PVDF‐based bilayer composite films with novel 3D conductive network were prepared. The synergistic EMI shielding mechanism of the film is discussed.

A Waterproof Flexible Paper-Based Thermoelectric Generator for Humidity and Underwater Environments.

A thermoelectric generator (TEG) is one of the important energy harvesting sources for wearable electronic devices, which converts waste heat into electrical energy without any external stimuli, such as light or mechanical motion. However, the poor flexibility of traditional TEGs (e.g., Si-based TE devices) causes the limitations in practical applications. Flexible paper substrates are becoming increasingly attractive in wearable electronic technology owing to their usability, environmental friendliness (disposable, biodegradable, and renewable materials), and foldability. The high water-absorbing quality of paper restricts its scope of application due to water failure. Therefore, we propose a high-performance flexible waterproof paper-based thermoelectric generator (WPTEG). A modification method that infiltrates TE materials into cellulose paper through vacuum filtration is used to prepare the TE modules. By connecting the TE-modified paper with Al tape, as well as a superhydrophobic layer encapsulation, the WPTEG is fabricated. The WPTEG with three P-N modules can generate an output voltage of up to 235 mV at a temperature difference of 50 K, which can provide power to portable electronic devices such as diodes, clocks, and calculators in hot water. With the waterproof property, the WPTEG paves the way for achieving multi-scenario applications in humid environments on human skin.

Degradable piezoelectric biomaterials for medical applications

The energy harvesting technology based on piezoelectricity promises to achieve a self-powered mode for portable medical electronic devices. Piezoelectric materials, as crucial components in electromechanical applications, have extensively been utilized in portable medical electronic devices. Especially, degradable piezoelectric biomaterials have received much attention in the medical field due to their excellent biocompatibility and biosafety. This mini-review mainly summarizes the types and structural characteristics of degradable piezoelectric biomaterials from degradable piezoelectric small-molecule crystals to piezoelectric polymers. Afterward, medical applications are briefly introduced, including energy harvester and sensor, actuator and transducer, and tissue engineering scaffold. Finally, from a material perspective, some challenges currently faced by degradable piezoelectric biomaterials are proposed.

Amorphous lithiophilic cobalt‐boride@rGO interlayer for dendrite‐free and highly stable lithium metal batteries

AbstractLithium metal batteries (LMBs) are recognized to be crucial for secondary battery technology targeting electric vehicles and portable electronic devices. However, the undesirable growth of lithium dendrites would result in reduced capacity, short‐circuit, and overheating, seriously hindering the practical applications of LMBs. To address this issue, a neoteric lithiophilic interlayer on a commercial polypropylene separator is presented for the first time, which is constructed by amorphous CoB nanoparticles decorated reduced graphene oxide nanosheets (CoB@rGO). Density Functional Theory calculations and experimental analysis reveal remarkable lithiophilicity features for CoB@rGO and provide multiple Li deposition sites and improved electrolyte wettability, which facilitates the formation of durable solid electrolyte interphase (SEI), reduces side reactions, and improves Li+ flux regulation for long‐term cycling stability in LMBs. Taking advantage of these merits, the symmetric Li//Li cell with CoB@rGO/PP separator exhibits stable cycling for up to 1600 h at 1 mA cm−2 with 1 mAh cm−2. Employed with CoB@rGO separator, the Li//LiFePO4 full cell with a high LiFePO4 loading of 11 mg cm−2 delivers a high initial specific capacity of 115.3 mAh g−1 and a low decay rate of 0.08% per cycle after 200 cycles even at a high rate of 2C.

Harnessing Green Electricity from Food: A Split Black Gram-Based Triboelectric Nanogenerator for a Self-Powered Autonomous Lighting System and Portable Electronics.

Triboelectric nanogenerators (TENGs) represent a promising solution to mounting environmental concerns associated with battery disposal amid the escalating demand for portable electronics. However, prevailing TENG fabrication predominantly relies on nonbiodegradable, nonbiocompatible, and synthetic materials, posing a grave ecological threat. To mitigate this, there is a pressing need to develop eco-friendly and green TENGs leveraging sustainable, naturally occurring materials. This study pioneers the use of split black gram (SBG) as a tribo-positive material for TENGs. SBG's effectiveness as a tribo-positive material stems from its abundance of oxygen-containing functional groups, as confirmed by FTIR analysis, facilitating electron donation during the triboelectric process. SBG offers compelling advantages, including widespread availability, cost-effectiveness, biodegradability, and hydrophobic and adhesive properties due to its richness in starch and protein, positioning it as an optimal choice for eco-conscious TENG manufacturing. The fabrication process of an SBG-TENG is not only economical and facile but also solvent-free, requiring no specialized tools. Demonstrating commendable performance, the SBG-TENG achieves a maximum power density of 15.36 μW/cm2 at 1 MΩ, with an open circuit voltage of 84 V and short circuit current of 28 μA, comparable to recent studies. In practical applications, the SBG-TENG seamlessly integrates with LEDs and portable electronic devices via a full bridge rectifier, successfully powering them postcapacitor charging. Moreover, an autonomous lighting system is developed by embedding the SBG-TENG in a foot mat, enabling wireless light control through human stepping on the mat, introducing power-saving functionality for residential and office environments. In essence, the introduction of the SBG-TENG not only delivers cost-effectiveness but also minimizes the environmental impact by harnessing sustainable energy from food sources.

Hydrogel-based flexible degradable triboelectric nanogenerators for human activity recognition

The development of Internet of Things (IoT) and Artificial Intelligence (AI) technologies has led to an increased demand for wearable electronic devices that can be used in a variety of contexts. Hydrogel sensors have been regarded as an ideal material for the fabrication of multifunctional flexible wearable devices. However, it is difficult to create hydrogel sensors with ideal electrical and mechanical properties. In this study, a conductive hydrogel prepared by a simple method has been introduced. The hydrogel was immersed in a binary solvent of glycerol, water and sodium citrate to form a transparent, long-term stable and highly conductive gelatin-NaCl organohydrogel (GNOH). A stretchable and durable gelatin Ecoflex triboelectric nanogenerator (GE-TENG) was created by combining an organic hydrogel with Ecoflex elastomer. It has high electrical and mechanical performance, with an open-circuit voltage of 142 V, current of 3.8 μA, power output of 19.36 μW and response time of 85 ms. Moreover, the single-electrode mode of the GE-TENG provides high electrical output for powering portable electronic devices and can capture biomechanical energy in temperatures as low as −20 °C. As a result of these capabilities, GE-TENG can effectively identify human movements with precision and transmit signals wirelessly, thereby broadening its potential applications. The GE-TENG-based self-powered intelligent sensing system (GSIS) for human-computer interaction demonstrates a wearable intelligent system for controlling the movement of a tank model and a manipulator by integrating the signal acquisition, signal processing and signal output components. The system achieves 100% signal recognition accuracy when combined with covariance matrix feature analysis and Convolutional Neural Network classification algorithms. This research demonstrates the potential of wearable hydrogel-based electronic devices for monitoring human motion, harvesting biomechanical energy and human-computer interaction.

A study on novel dual-functional photothermal material for high-efficient solar energy harvesting and storage

The solar-heat storage efficiency of devices based on phase change materials (PCMs) is limited due to the light absorption and internal heat transfer within the PCMs, unclear thermal conductivity-enhancement mechanism within nanocomposite PCMs, and uncontrollable photothermal-interface modulation. Therefore, a novel controllable strategy was proposed in this study to fabricate dual-functional photothermal storage three-dimensional (3D) phase change blocks (PCBs) with higher thermal conductivity (27.98 W/m·K) and spectral absorption (98.03 %) compared to those of most previously reported PCM-based devices. The as-synthesized PCBs contained millimeter-sized graphite plates with horizontal Van der Waals bonds and oriented micro/nanoscale graphite nanosheets. The structural properties of thin PCM layers between the PCB sheets have synergistically reduced the internal interfacial thermal resistance of the PCBs. Laser-controllable induction was used to fabricate integrated biomimetic-forest 3D optical absorbers on the high thermal conductivity interface of the PCBs, which significantly reduced the thermal resistance of the optical-thermal interface. The resulting 3D-PCBs, integrated with thermoelectric generators, powered portable electronic devices, expanding the applications of traditional PCM heat-storage devices. Therefore, this study will guide the future design of high-performance solar-thermal storage PCMs with a wide range of practical applications.

ТЕСТОВИЙ КОНТРОЛЬ РІВНЯ СФОРМОВАНОСТІ АНГЛОМОВНОЇ ЛЕКСИЧНОЇ КОМПЕТЕНТНОСТІ У ЗДОБУВАЧІВ ОСВІТИ ЗАСОБАМИ МОБІЛЬНИХ ТЕХНОЛОГІЙ

The article is devoted to the problem of the formation of English lexical competence among students of basic secondary education. It was found that the introduction of digital technologies, in particular, mobile technologies, into the educational process will be effective. It was found that they can become a catalyst for active language learning, providing students with the opportunity to improve their skills and identify needs for further development. It was found that the use of mobile technologies for test control makes it possible to take into account the individual characteristics of learning, to stimulate the active participation of students in their own learning and to ensure constant monitoring of their progress. The purpose of the article is determined: to study the peculiarities of conducting a test control of the level of formation of English lexical competence in students of basic secondary education by means of mobile technologies. The essence of mobile technologies, which is determined by the range of portable electronic devices that make it possible to optimize learning processes, is clarified. The means of mobile technologies for the formation of English-language lexical competence in students of education are outlined. Levels of formation of English lexical competence (initial, intermediate, advanced), mobile applications for diagnosis (Quizizz, Quizlet, Duolingo, Google Forms, Socrative, Cambridge English Dictionary) and features of test control (flexibility of time and place, interactivity and multimedia, adaptability) are determined tests, individual learning trajectory, communication and information exchange, fraud protection, access control, automated processing of results, online resources for additional study). It was found that the integration of innovative approaches, consideration of individual needs and systematic monitoring of progress by means of test control can significantly increase the effectiveness of training and prepare students of basic secondary education for the challenges of global society. Key words: mobile technologies, application, English lexical competence, education seeker.

Thermal management of Li-ion battery by using eutectic mixture of phase-change materials

Lithium-ion batteries have a wide range of applications in portable electronic devices, global positioning systems, and the automobile industry due to their remarkable attributes like high energy density, long life cycle, higher efficiency, low self-discharging, and worthier operational performance. Although under different vigilant operating parameters, lithium-ion batteries generate a significant amount of heat, which deteriorates their performance and can lead to thermal runaway. To mitigate this issue and to improve safety, battery life, capacity, and overall performance, a robust thermal management system is very necessary. This study scrutinizes the effect of a passive cooling method using phase-change materials and their eutectic mixture on a 2600 mAh lithium-ion battery pack during the charging and discharging at various C-rates (1C, 1.5C, and 2C). Phase-change materials used in the experimentation are salt hydrates namely calcium nitrate tetrahydrate and zinc nitrate hexahydrate and their eutectic mixture contains 55 % calcium nitrate tetrahydrate and 45 % zinc nitrate hexahydrate. Experimental results reveal that without the usage of any phase-change material, the highest temperature was recorded at a 2C rate due to high current, with cell 5 recording a temperature of 60.98 °C. Zinc nitrate hexahydrate reduced the temperature by 18.98 °C to maintain it at 42 °C, and calcium nitrate tetrahydrate led to a temperature drop of 14.48 °C, maintaining it at 46.50 °C. The eutectic mixture caused a temperature reduction of 21.97 °C, maintaining it at 39.01 °C. The results of this study illustrate that the implementation of eutectic mixture as a phase-change material diminishes both the maximum surface temperature and the temperature gradient. This implies its efficacy as a viable material for the cooling of battery packs.

Synthesis of Co@CoO/C by micro-tube method and their electrochemical performances

Lithium-ion batteries (LIBs) are promising secondary batteries that are widely used in portable electronic devices, electric vehicles and smart grids. The design and synthesis of high-performance electrode materials play a crucial role in achieving lithium-ion batteries with high energy density, prolonged cycle life, and superior safety. CoO has attracted significant attention as a negative electrode material for lithium-ion batteries due to its high theoretical capacity and abundant resources. However, its limited conductivity and suboptimal cycling performance impede its potential applications. The study proposes a novel micro-tube reaction method for the synthesis of Co@CoO/C, utilizing Kapok fiber as a template with a special hollow structure. The microstructure and composition of the samples were characterized using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After conducting electrochemical performance tests, it was discovered that at a current density of 100 mA/g and within the range of 0.01–3.0 V for 50 charge and discharge cycles. Co@CoO/C composite negative electrode exhibits a reversible lithium insertion specific capacity of 499.8 mAh/g and keep a discharge capacity retention rate of 97.6 %. The greatly improved lithium storage and stability performance of Co@CoO/C composite anode is mainly attributed to the synergistic effect between Co@CoO nanoparticles and the kapok carbon microtubule structure.

Designing intimately interconnected neuron-shaped nickel-copper(I) sulfide nanocomposites as cathode material for supercapacitors

Nanostructured transition metal sulfides have attracted significant attention as pseudocapacitance materials owing to their high specific capacitance and improved conductivity compared to oxides. Bimetallic nickel‑copper(I) (NiCu) sulfides are promising candidates for use in asymmetric supercapacitors because of their high specific capacitance, wide voltage range, and high conductivity. In this study, we synthesize neuron-shaped Ni-Cu(I) sulfide nanocomposites with intimate interconnectivity via the sulfidation and ion exchange of Ni-Cu(I) carbonate hydroxide, prepared by a straightforward hydrothermal process. The product's unique structure, featuring a neuronal network, exhibits a high specific capacitance of 1226.5 F g−1 at 1 A g−1 and an excellent cycling stability (88.97 % capacitance retention after 5000 cycles), which is attributed to the coexistence of bimetallic components and an inherently interconnected neuron-shaped configuration that prevents structural collapse and self-aggregation, while providing easy electrolyte accessibility. Furthermore, an asymmetric supercapacitor with a Ni-Cu(I) sulfide cathode material demonstrates a maximum power and energy densities of 9000 W kg−1 and 23.99 Wh kg−1, respectively, with an initial capacity retention rate of 83.69 % after 5000 cycles. The distinctive structural features of Ni-Cu(I) sulfides enhance the energy storage capabilities of the nanomaterials, enabling the development of portable electronic devices.