Structural batteries: Advances,challenges and perspectives

The development of light-weight batteries has a great potential value for mobile applications, including electric vehicles and electric aircraft. Along with increasing energy density, another strategy for reducing battery weight is to endow energy storage devices with multifunctionality – e.g., creating an energy storage device that is able to bear structural loads and act as a replacement for structural components such that the weight of the overall system is reduced. This type of batteries is commonly referred to as “structural batteries”. Two general methods have been explored to develop structural batteries: (1) integrating batteries with light and strong external reinforcements, and (2) introducing multifunctional materials as battery components to make energy storage devices themselves structurally robust. In this review, we discuss the fundamental rules of design and basic requirements of structural batteries, summarize the progress made to date in this field, examine potential avenues and sources of inspiration for future research, and touch upon challenges remaining in this field such as safety, costs, and performance stability. Though more fundamental and technical research is needed to promote wide practical application, structural batteries show the potential to significantly improve the performance of electric vehicles and devices.     

Microwave hydrothermal synthesis of lanthanum oxyfluoride nanorods for photocatalytic nitrogen fixation: Effect of Pr doping

Photocatalytic fixation of nitrogen has been recognized as a green and promising strategy for ammonia synthesis under ambient conditions. However, the efficient reduction of nitrogen remains a challenge due to high activation energy of nitrogen and low utilization of solar energy. Herein, lanthanum oxyfluoride with different doping content of Pr³⁺ (LaOF:xPr³⁺) upconversion nanorods were synthesized by microwave hydrothermal method. Results indicated that the doping of Pr³⁺ generated considerable defects on the surface of LaOF which acted as the adsorption and activation center for nitrogen. Meanwhile, the Pr³⁺ ion narrowed the band gap and broadened the light response range of LaOF because LaOF:Pr³⁺ can upconvert visible light into ultraviolet light, which excite LaOF nanorods and improve the utilization of solar light. The doping amount of Pr³⁺ had critical effect on the photocatalytic nitrogen fixation performance which reached as high as 180 μmol·L⁻¹·h⁻¹ when the molar ratio of Pr³⁺ to LaOF was optimized to be 2%.     

Palaeoenvironmental reconstruction in the Southern Levant: synthesis, challenges, recent developments and perspectives

Palaeoenvironmental research in the Southern Levant presents a series of challenges, partly due to the unequal distribution of palaeoenvironmental records and potential archives throughout the region. Our knowledge of climatic evolution, during the last approximately 25,000 years, is of crucial importance to understand cultural developments. More local, well-dated, multi-proxy studies are much needed to obtain an accurate picture of environmental change in respect of the Late Pleistocene and the Holocene. This contribution reviews the current state of knowledge regarding Late Quaternary palaeoenvironmental changes in the Southern Levant, including some examples of more recent developments in palaeoenvironmental reconstruction in Israel and the Dead Sea area, and introduces the major challenges researchers face in the region. It also presents the first results of a new case study in Jordan, based on an analysis of peaty deposits located in the mountain slopes east of the Dead Sea. Such new studies help refine our knowledge of local environmental changes in the Southern Levant and especially the more arid areas, for which little information is presently available. More material suitable for palaeoenvironmental research, for example extensive tufa and travertine series, still awaits consideration in Jordan, opening up exciting perspectives for future research in the area.     

One-step synthesis of N,P co-doped porous carbon electrocatalyst for highly efficient nitrogen fixation

Heteroatom-doped porous carbon has attracted many researchers'interests owing to their hierarchical porous and more active sites for nitrogen reduction reaction...     

Nanostructured electrodes for lithium-ion and lithium-air batteries: the latest developments, challenges, and perspectives

The urgency for clean and secure energy has stimulated a global resurgence in searching for advanced electrical energy storage systems. For now and the foreseeable future, batteries remain the most promising electrical energy storage systems for many applications, from portable electronics to emerging technologies such as electric vehicles and smart grids, by potentially offering significantly improved performance, energy efficiencies, reliability, and energy security while also permitting a drastic reduction in fuel consumption and emissions. The energy and power storage characteristics of batteries critically impact the commercial viability of these emerging technologies. For example, the realization of electric vehicles hinges on the availability of batteries with significantly improved energy and power density, durability, and reduced cost. Further, the design, performance, portability, and innovation of many portable electronics are limited severely by the size, power, and cycle life of the existing batteries. Creation of nanostructured electrode materials represents one of the most attractive strategies to dramatically enhance battery performance, including capacity, rate capability, cycling life, and safety. This review aims at providing the reader with an understanding of the critical scientific challenges facing the development of advanced batteries, various unique attributes of nanostructures or nano-architectures applicable to lithium-ion and lithium-air batteries, the latest developments in novel synthesis and fabrication procedures, the unique capabilities of some powerful, in situ characterization techniques vital to unraveling the mechanisms of charge and mass transport processes associated with battery performance, and the outlook for future-generation batteries that exploit nanoscale materials for significantly improved performance to meet the ever-increasing demands of emerging technologies.     

Carbon nanotube based transparent conductive films: progress,challenges, and perspectives

Developments in the manufacturing technology of low-cost, high-quality carbon nanotubes (CNTs) are leading to increased industrial applications for this remarkable material. One of the most promising applications, CNT based transparent conductive films (TCFs), are an alternative technology in future electronics to replace traditional TCFs, which use indium tin oxide. Despite significant price competition among various TCFs, CNT-based TCFs have good potential for use in emerging flexible, stretchable and wearable optoelectronics. In this review, we summarize the recent progress in the fabrication, properties, stability and applications of CNT-based TCFs. The challenges of current CNT-based TCFs for industrial use, in comparison with other TCFs, are considered. We also discuss the potential of CNT-based TCFs, and give some possible strategies to reduce the production cost and improve their conductivity and transparency.     

Alloy design via additive manufacturing: Advantages,challenges, applications and perspectives

Additive manufacturing (AM) has rapidly changed both large- and small-scale production environments across many industries. By re-envisioning parts from the ground up, not limited to the challenges presented by traditional manufacturing techniques, researchers and engineers have developed new design strategies to solve large-scale materials and design problems worldwide. This is particularly true in the world of alloy design, where new metallic materials have historically been developed through tedious processes and procedures based primarily on casting methodologies. With the onset of directed energy deposition (DED) and powder bed fusion (PBF)-based AM, new alloys can be innovated and evaluated rapidly at a lower cost and considerably shorter lead time than has ever been achieved. This article details the advantages, challenges, applications, and perspectives of alloy design using primarily laser-based AM. It is envisioned that researchers in industry and academia can utilize this work to design new alloys leveraging metallic AM processes for various current and future applications.     

A rapid and facile method for hydrothermal synthesis of CdTe nanocrystals under mild conditions

By using a novel procedure, a new kind of water-soluble CdTe nanocrystals (NCs) is synthesized in aqueous solutions at the temperature of 100 degrees C. In this procedure, tripeptide thiol glutathione was used as stabilizing agent, CdTe NCs with controllable photoluminescence wavelength from 500 nm to 680 nm were prepared within two hours. Compared with CdTe NCs prepared with thiohydracrylic acid as stabilizing agent, as-prepared NCs show much narrower photoluminescence FWHM, more symmetrical emission peak and higher photoluminescence quantum yield. The surface structure of as-prepared CdTe NCs is deduced, therefore, there may be some unreported circular structure on the surface. Experimental results show that as-prepared NCs have very good biological compatibility and they are nontoxic. And these CdTe NCs can conjugate with biological molecules for further biological luminescence study. The proposed hydrothermal synthesis procedure has the advantage of simplicity, inexpensiveness, time saving and mild operating conditions.     

Reverse engineering and identification in systems biology: strategies,perspectives and challenges

The interplay of mathematical modelling with experiments is one of the central elements in systems biology. The aim of reverse engineering is to infer, analyse and understand, through this interplay, the functional and regulatory mechanisms of biological systems. Reverse engineering is not exclusive of systems biology and has been studied in different areas, such as inverse problem theory, machine learning, nonlinear physics, (bio)chemical kinetics, control theory and optimization, among others. However, it seems that many of these areas have been relatively closed to outsiders. In this contribution, we aim to compare and highlight the different perspectives and contributions from these fields, with emphasis on two key questions: (i) why are reverse engineering problems so hard to solve, and (ii) what methods are available for the particular problems arising from systems biology?     

A Review on Graphene Fibers: Expectations,Advances, and Prospects

Graphene fiber (GF) is a macroscopically assembled fibrous material made of individual units of graphene and its derivatives. Beyond traditional carbon fibers, graphene building blocks consisting of regulable sizes and regular orientations of GF are expected to generate extreme mechanical and transport properties, as well as multiple functions in smart electronic fibrous devices and textiles. Here, the features of GF are presented along four lines: preparation, morphology, structure–performance correlations, and state-of-the-art applications as flexible and wearable electronics. The principles, experiments, and keys of fabricating GF from graphite with different methods, focusing on the industrially viable mainstream strategy, wet spinning, are introduced. Then, the fundamental relationship between the mechanical and transport properties and the structure, including both highly condensed structures for high-performance and hierarchical structures for multiple functions, is presented. The advances of GF based on structure–performance formulas boost its functional applications, especially in electronic devices. Finally, the possible promotion methods and structural–functional integrated applications of GF are discussed.     

Facile one-step synthesis of MnO2 nanowires on graphene under mild conditions for application in supercapacitors

Composites of integrated 1-D MnO₂ nanowires and 2-D graphene sheets at nanoscale are successfully prepared under the mild condition of 100 °C. The fabricated materials are extensively characterized by electron microscopy and X-ray diffraction, and the formation mechanism is investigated. It is of particular note that the graphene sheets in this case play dual roles, both as active reagent to reduce MnO^4? to form 1-D MnO₂ nanowires and as active component of the composites integrated into the 3-D structure. The proof-of-concept demonstration shows that the 3-D composites can be used as active materials for supercapacitors, where the high-surface area 2-D graphene sheets serve as both high-surface area active materials and conductive supports for high-capacity 1-D MnO₂ nanowires.     

Neodymium-doped copper ferrite: auto-combustion synthesis,characterization and photocatalytic properties

Neodymium doped copper ferrite nanoparticles were successfully synthesized by via a sol–gel auto combustion method with the aid of copper (II) nitrate, iron (III) nitrate, neodymium (III) nitrate and starch without adding external surfactant. Moreover, starch plays role as capping agent, reductant agent, and natural template in the synthesis CuFe_2?xNd_xO₄ nanoparticles. The as-synthesized CuFe_2?xNd_xO₄ nanoparticles were characterized by means of several techniques such as X-ray diffraction, scanning electron microscopy, energy dispersive X-ray microanalysis and UV–Vis diffuse reflectance spectroscopy. The magnetic properties of as-prepared CuFe_2?xNd_xO₄ nanoparticles were also investigated with vibrating sample magnetometer (VSM). To evaluate the photocatalyst properties of nanocrystalline CuFe_2?xNd_xO₄, the photocatalytic degradation of methyl orange (MO) under ultraviolet light irradiation was carried out.     

Advances and perspectives on one-dimensional nanostructure electrode materials for potassium-ion batteries

Potassium-ion batteries (PIBs) have aroused considerable interest as a promising next-generation advanced large-scale energy storage system due to the abundant potassium resources and high safety. However, the K⁺ with large ionic radius brings restricted diffusion kinetics and severe volume expansion in electrode materials, resulting in inferior actual rate characteristics and rapid capacity fading. Designing electrode materials with one-dimensional (1D) nanostructure can effectively enhance various electrochemical properties due to the well-guided electron transfer pathways, short ionic diffusion channels and high specific surface areas. In this review, we summarize the recent research progress and achievements of 1D nanostructure electrode materials in PIBs, especially focusing on the development and application of cathode and anode materials. The nanostructure, synthetic methods, electrochemical performances and structure-performance correlation are discussed in detail. The advanced characterizations on the reaction mechanisms of 1D nanostructure electrode materials in PIBs are briefly summarized. Furthermore, the main future research directions of 1D nanostructure electrode materials are also predicted, hoping to accelerate their development into the practical PIBs market.     

Mesoporous zinc-blende ZnS nanoparticles: synthesis, characterization and superior photocatalytic properties

This paper describes the development of a novel and simple chemical route to mass production of mesoporous ZnS nanoparticles in high yield. XRD, FESEM, TEM, SAED, EDS and XPS analyses show that spherical nanoparticles are crystalline ZnS in a zinc-blende structure. The resulting nanoparticles have an average diameter of about 30 nm and pore sizes in the range of 3-6?nm. The formation of mesoporous nanostructures could be attributed to higher nucleation rate in the course of preparation that resulted in the quick aggregation of initial crystallites and the formation of pores between them. The as-prepared mesoporous ZnS exhibited excellent photocatalytic activities. This preparation method provides one possible route to the synthesis of other mesoporous structures for exploratory studies on the applications of mesoporous nanocrystals.     

Advances in graphene-related technologies: synthesis, devices and outlook

Graphene has been the subject of many scientific investigations since exfoliation methods facilitated isolation of the two-dimensional material. During this time, new synthesis methods have been developed which have opened technological opportunities previously hindered by synthetic constraints. An update on the recent advances in graphene-based technologies, including synthesis and applications into electrical, mechanical and thermal uses will be covered. A special focus on the patent space and commercial landscape will be given in an effort to identify current trends and future commercialization of graphene-related technologies.     

Review on oxides of antimony nanoparticles: synthesis,properties, and applications

In this article, synthesis methods, properties, and applications of antimony oxide nanoparticles are reviewed. Oxides of antimony exist in three phases, namely antimony trioxide, antimony tetroxide, and antimony pentoxide. Physical and optical properties of these nanoparticles are reviewed and compared with their bulk forms. According to literature works, a total of eight synthesis methods have been used to produce these nanoparticles. The size, distribution, shape, and structure of the nanoparticles which are synthesized by different methods are compiled and compared. It is reported that the properties are strongly dependent on the synthesis methods. Advantages and disadvantages of each synthesis method are discussed and compared. Most literatures report on the optical and physical properties of the nanoparticles. Reports on the electrical properties are scarce. As the applications of these nanoparticles cover a wide range, several challenges must be overcome to use them well. These challenges are also being presented and explained in this article.