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Abstract MXenes and their derivatives have attracted tremendous attention over the past few decades, and several reviews have already been dedicated to their synthesis, properties, device functionalities, and performances. Nitrogen (i.e., N), as an important non‐metal element, has been widely reported as an external dopant to improve the properties of MXenes. Herein, we review the recent advances of N‐MXenes, with a significant concern on the impact of N‐doping on the structural and photo‐/electrochemical properties of bulk MXenes, and their emerging applications. The different types of recently reported N‐MXenes and the associations between the N‐doping and the structural characteristics (e.g., the change of atomic lattice and the number and type of active sites, as well as the removal of detrimental functional groups) of MXenes are systematically summarized and discussed, with the aim to highlight the resulting improvements in response to the photo‐/electrochemical and electronic stimuli. Applications of the N‐MXenes in the fields of electrochemistry, photo‐/electrocatalysis, and photosensing are then described. Finally, we summarize this review, and disclose our perspectives on the future opportunities of the N‐MXenes and the potential development challenges of this research branch.

Abstract Waste tyres (WTs) are a major global issue that needs immediate attention to ensure a sustainable environment. They are often dumped in landfills or incinerated in open environments, which leads to environmental pollution. However, various thermochemical conversion methods have shown promising results as treatment routes to tackle the WT problem while creating new materials for industries. One such material is WT char, which has properties comparable to those of carbon materials used as an active electrode material in batteries. Therefore, a systematic review of the various thermochemical approaches used to convert WTs into carbon materials for electrode applications was conducted. The review shows that pretreatment processes, various process routes, and operating parameters affect derived carbon properties and its respective electrochemical performance. WT‐derived carbon has the potential to yield a high specific capacity greater than the traditional graphite (372 mAh g−1) commonly used in lithium‐ion batteries. Finally, the review outlines the challenges of the process routes, as well as opportunities and future research directions for electrode carbon materials from WTs.

Abstract Supercapacitors (SCs) are studied and used in various fields due to their high power density, fast charging/discharging rate, as well as long cycle life. Compared to other traditional electrode and electrolyte materials, supramolecular hydrogels have great advantages in the application of SCs due to their excellent properties. Unlike covalent bonds, supramolecular systems are assembled through dynamic reversible bonds, including host–guest interactions, ion interactions, electrostatic interactions, hydrogen bonding, coordination interactions, etc. The resulting supramolecular hydrogels show some special functions, such as stretching, compression, adhesion, self‐healing, stimulus responsiveness, etc., making them strong candidates for the next generation of energy storage devices. This paper reviews the representative progress of electrodes, electrolytes, and SCs based on supramolecular hydrogels. Besides, the properties of supramolecular hydrogels, such as conductivity, extensibility, compressibility and elasticity, self‐healing, frost resistance, adhesion, and flexibility, are also reviewed to highlight the key role of excellent properties of hydrogel materials in SCs. In addition, this article also discusses the challenges faced by current technologies, hoping to continue promoting future research in this field.

Abstract Sodium‐ion batteries (NIBs) have emerged as a promising alternative to commercial lithium‐ion batteries (LIBs) due to the similar properties of the Li and Na elements as well as the abundance and accessibility of Na resources. Most of the current research has been focused on the half‐cell system (using Na metal as the counter electrode) to evaluate the performance of the cathode/anode/electrolyte. The relationship between the performance achieved in half cells and that obtained in full cells, however, has been neglected in much of this research. Additionally, the trade‐off in the relationship between electrochemical performance and cost needs to be given more consideration. Therefore, systematic and comprehensive insights into the research status and key issues for the full‐cell system need to be gained to advance its commercialization. Consequently, this review evaluates the recent progress based on various cathodes and highlights the most significant challenges for full cells. Several strategies have also been proposed to enhance the electrochemical performance of NIBs, including designing electrode materials, optimizing electrolytes, sodium compensation, and so forth. Finally, perspectives and outlooks are provided to guide future research on sodium‐ion full cells.

Abstract Solid‐state supercapacitors (SSCs) are emerging as one of the promising energy storage devices due to their high safety, superior power density, and excellent cycling life. However, performance degradation and safety issues under extreme conditions are the main challenges for the practical application. With the expansion of human activities, such as space missions, polar exploration, and so on, the investigation of SSC with wide temperature tolerance, high energy density, power density, and sustainability is highly desired. In this review, the effects of temperature on SSC are systematically illustrated and clarified, including the properties of the electrolyte, ion diffusion, and reaction dynamics of the supercapacitor. Subsequently, we summarize the recent advances in wide‐temperature‐range SSCs from the aspect of electrolyte modification, electrode design, and interface adjustment between electrode and electrolyte, especially with critical concerns on ionic conductivity and cycling stability. In the end, a perspective is presented, expecting to promote the practical application of the SSC in harsh conditions.

Abstract The design and fabrication of flexible, porous, conductive electrodes with customizable functions become the prime challenge in the development of new‐generation wearable electronics, especially for rechargeable batteries. Here, the NiCo bialloy particulate catalyst‐loaded self‐supporting carbon foam framework (NiCo@SCF) as a flexible electrode has been fabricated through one facile adsorption‐pyrolysis method using a commercial melamine foam. Compared with the electrode with Pt/C and Ir/C benchmark catalysts, the NiCo@SCF electrode exhibited superior bifunctional electrocatalytic performance in alkaline media with a half‐wave potential of 0.906 V for oxygen reduction reaction, an overpotential of 286 mV at j = 10 mA cm−2 for oxygen evolution reaction, and stable bifunctional performance with a small degradation after 20,000 voltammetric cycles. The as‐assembled aqueous zinc–air battery (ZAB) with NiCo@SCF as a self‐supporting air cathode demonstrated a high peak power density of 178.6 mW cm−2 at a current density of 10 mA cm−2 and a stable voltage gap of 0.94 V over a 540 h charge−discharge operation. Remarkably, the as‐assembled flexible solid‐state ZAB with self‐supporting NiCo@SCF as the air cathode presented an engaging peak power density of 80.1 mW cm−2 and excellent durability of 95 h undisrupted operation, showing promise for the design of wearable ZAB. The demonstrated electrode fabrication approach exemplifies a facile, large‐scale avenue toward functional electrodes, potentially extendable to other wearable electronics for broader applications.

Abstract High‐performance multilayer dielectric elastomer actuators (DEAs) are well‐positioned to overcome the insufficient output force and energy density as artificial muscles. However, due to the fabrication process, the multilayer DEAs with nonmodifiable structures often suffer from the limitation of short lifespans and scalable preparation. Herein, reusable multilayer DEAs with the detachable and reconfigurable structure are fabricated. This is achieved by realizing scalable compliant electrodes using the continuous spatial confining forced network assembly (CSNA) method and combining the vacuum lamination (VL) approach to have good attachability and detachability with the VHB dielectric elastomer. The flexible roller‐based CSNA method is used to prepare the large area compliant electrodes composed of α, ω‐dihydroxy polydimethylsiloxane and electrically conductive nanoparticles. The fabricated electrodes can continuously work over 10 000 cycles at 40% strained stretching and maintain smooth surfaces to construct multilayer DEAs. Moreover, owing to the detachable configuration of the DEAs, the electrodes can also be recovered and reused for building new actuators. The lower limb assistive device is demonstrated by detachable multilayer spring roll DEAs, achieving approximately 3.1 degrees of flexion and extension movement of knee models under a voltage of 7 kV. The detachable and reconfigurable multilayer DEAs shed new light on the applications of wearable assistive devices.

Spinal cord stimulation (SCS) represents a therapeutic approach for chronic pain management in patients refractory to conventional treatments. By implanting electrodes in the epidural space, SCS aims to mitigate pain transmission to the brain through electrical stimulation, often resulting in sensory perceptions such as paresthesia. This study investigates the influence of electrode configurations on electrical parameters, including current density and electric potential, within the spinal cord environment. Utilizing computational models of the spinal canal incorporating components such as epidural fat, cerebrospinal fluid (CSF), gray matter, and white matter, our analysis explores the distribution of electric potential and current density. Specifically, configurations employing four and nine electrodes are evaluated under both direct current (DC) and alternating current (AC) stimulations. For DC stimulations at currents of 1, 5, and 10 mA, our findings indicate that the four-electrode model generated current density values in epidural fat ranging from 107.90 to 130.98 mA/cm 2 and electric potential values ranging from 3.51 to 4.78 V. Similarly, the nine-electrode model produced current density values ranging from 92.51 to 223.61 mA/cm 2 and electric potential values ranging from 1.27 to 7.83 V under the same conditions. The results demonstrate a proportional relationship between applied current, current density, and electric potential. Furthermore, our investigation reveals a gradual decrease in electrical potential and current density from the epidural space to the gray matter. Discussions encompass the safety implications of these findings, examining whether the observed electrical parameters remain within tolerable limits for patient well-being. Additionally, the study explores the effects of AC stimulation across frequencies ranging from 250 Hz to 10 kHz, revealing an inverse correlation between frequency and charge parameters. Specifically, higher frequencies corresponded to reduced charge per phase and charge density, underscoring the frequency-dependent nature of these electrical properties., (© 2024 John Wiley & Sons Ltd.)

Abstract One of the most exciting new developments in energy storage technology is flexible Zn‐ion hybrid supercapacitors (f‐ZIHSCs), which combine the high energy of Zn‐ion batteries with high‐power supercapacitors to satisfy the needs of portable flexible electronics. However, the development of f‐ZHSCs is still in its infancy, and there are numerous barriers to overcome before they can be widely implemented for practical applications. This review gives an up‐to‐date description of recent achievements and underlying concepts in energy storage mechanisms of f‐ZIHSCs and emphasizes the critical role of cathode, anode, and electrolyte materials systems in speeding the prosperity of f‐ZIHSCs. The innovative nanostructured‐based cathode materials for f‐ZIHSCs include carbon (e.g., porous carbon, heteroatom‐doped carbon, biomass‐derived porous carbon, graphene, etc.), metal‐oxides, MXenes, and metal/covalent‐organic frameworks, and other materials (e.g., activated carbon, phosphorene, etc.) are mainly focused. Afterward, the latest developments in flexible anode and electrolyte frameworks and impacts of electrolyte compositions on the electrochemical properties of f‐ZIHSC are elaborated. Subsequently, the advancements based on fabrication designs, including quasi‐solid‐state, micro, fiber‐shaped, and all climate‐changed f‐ZIHSCs, are discussed in detail. Lastly, a summary of current challenges and recommendations for the future progress of advanced f‐ZIHSC are addressed. This review article is anticipated to further understand the viable strategies and achievable approaches for assembling high‐performance f‐ZIHSCs and boost the technical revolutions on cathode, anode, and electrolytes for f‐ZIHSC devices.

Abstract Purpose Ankle swelling (AS) is one of the main complaints in athletes with a lateral ankle sprain (LAS) in the acute phase. Reducing AS may help the athlete to return to training faster. The purpose of this study was to evaluate the efficacy of Kinesio Taping® (KT) and neuromuscular electrical stimulation (NMES) in reducing AS in athletes with a LAS. Methods Thirty‐one athletes with a unilateral ankle sprain from various sports were allocated to either KT (N = 16; mean age of 24.1 years) or NMES (N = 15; mean age of 26.4 years) groups. KT was applied over the medial and lateral ankle surfaces in the Fan cut pattern for five consecutive days; however, NMES was applied to the tibialis anterior and gastrocnemius muscles for 30 min. Outcome measures to assess the extent of AS included volumetry, perimetry, relative volumetry, and the difference in both ankles’ volumetry and perimetry at baseline, after the interventions, and 15 days following the treatment completion. Results The results of the mixed model repeated measures ANOVA demonstrated no significant difference between the two groups in mean changes in outcomes over pre‐ and post‐interventions as well as follow‐up periods (P > 0.05). Conclusions None of the KT and NMES methods could reduce acute AS in athletes with LAS. Further studies are needed in this area of research that consider changes in treatment protocol given the variety of NMES approaches and KT applications that can be used in recovery from an ankle sprain.

Abstract In recent years, the focus on the utilization of renewable energy has continued to heat up. However, renewable energy has the drawbacks of intermittency and mismatch between power generation and electricity consumption in time and space, thus the energy storage system is indispensable. Redox flow batteries (RFBs), as an electrochemical energy storage system, have attracted widespread attention with the nature of flexible design and long service life. The components of RFB and the efficient combination of components play a key role in battery performance. Due to the size effect and physicochemical properties of nanoparticles, the ionic conductivity, thermal conductivity, and mechanical effects are improved in RFBs with the addition of nanoparticles, thus improving the power performance and charge–discharge cycle life of the battery. In this review paper, we mainly report the application and research progress of nanoparticles applied in RFBs. The applications of nanoparticles in electrode, electrolyte, and proton (ion) exchange membranes in aqueous and nonaqueous RFBs are briefly introduced, with emphasis on adjusting the type, size, surface treatment, loading method, and loading quality of nanoparticles. The transport property and electrochemical reaction rate of active species and charges in RFBs can be improved after the inclusion of nanoparticles, leading to the improvement of the power density, energy efficiency, and stability of the battery. The applications and research progress of nanoparticles in RFBs can be systematically and comprehensively understood via the analyses and discussions in this review. It also provides a new technical idea to promote the commercial development and deployment of high‐performance RFB.

Dielectric response measurement is a widely used technique for characterising dielectric materials in terms of their capacitance and dielectric loss. However, the widely used approach with contact between samples and electrodes can in some cases limit the accuracy of the measurement. The authors introduce an easily realised electrode arrangement for non-contact measurements, which avoids these contact problems. The performance of the electrode arrangement in terms of the edge effect is assessed. The non-contact and contact methods are compared based on error-sensitivity analysis and experimental results. Differences are studied further, with attention to contact pressure. The non-contact method is also compared experimentally with the one-sided non-contact method. Air-reference measurements, comparing the sample to an air-gap for improved calibration, are used for all measurements. The results show that the non-contact method can be an alternative to reduce contact problems between the sample and electrodes, although error sensitivity can be higher when the non-contact method is used. The non-contact method can decrease the influence of the pressure applied to the sample compared to the contact method, and can also reduce the problem of poor contact that can arise from the absence of pressure in the one-sided non-contact method.

The vanadium redox flow battery (VRFB) is a highly regarded technology for large-scale energy storage due to its outstanding features, such as scalability, efficiency, long lifespan, and site independence. This paper provides a comprehensive analysis of its performance in carbon-based electrodes, along with a comprehensive review of the system's principles and mechanisms. It discusses potential applications, recent industrial involvement, and economic factors associated with VRFB technology. The study also covers the latest advancements in VRFB electrodes, including electrode surface modification and electrocatalyst materials, and highlights their effects on the VRFB system's performance. Additionally, the potential of two-dimensional material MXene to enhance electrode performance is evaluated, and the author concludes that MXenes offer significant advantages for use in high-power VRFB at a low cost. Finally, the paper reviews the challenges and future development of VRFB technology., (© 2023 The Chemical Society of Japan & Wiley-VCH GmbH.)