Advanced Materials

Graphene đang thu hút sự quan tâm mạnh mẽ trong các lĩnh vực như vật lý, hóa học và khoa học vật liệu, cùng nhiều lĩnh vực khác. Sự quan tâm đến các tính chất vật lý đặc biệt, khả năng điều chỉnh hóa học và tiềm năng ứng dụng của graphene đã tạo ra hàng ngàn công trình nghiên cứu và một nhịp độ nghiên cứu đang gia tăng, làm cho việc đánh giá các nghiên cứu này trở nên kịp thời. Bài báo này cung cấp cái nhìn tổng quan về các phương pháp tổng hợp, tính chất, và ứng dụng của graphene và các vật liệu liên quan (chủ yếu là oxit graphit và các huyền phù keo cùng các vật liệu từ chúng), từ góc nhìn của khoa học vật liệu.

This article provides a comprehensive review of current research activities that concentrate on one‐dimensional (1D) nanostructures—wires, rods, belts, and tubes—whose lateral dimensions fall anywhere in the range of 1 to 100 nm. We devote the most attention to 1D nanostructures that have been synthesized in relatively copious quantities using chemical methods. We begin this article with an overview of synthetic strategies that have been exploited to achieve 1D growth. We then elaborate on these approaches in the following four sections: i) anisotropic growth dictated by the crystallographic structure of a solid material; ii) anisotropic growth confined and directed by various templates; iii) anisotropic growth kinetically controlled by supersaturation or through the use of an appropriate capping reagent; and iv) new concepts not yet fully demonstrated, but with long‐term potential in generating 1D nanostructures. Following is a discussion of techniques for generating various types of important heterostructured nanowires. By the end of this article, we highlight a range of unique properties (e.g., thermal, mechanical, electronic, optoelectronic, optical, nonlinear optical, and field emission) associated with different types of 1D nanostructures. We also briefly discuss a number of methods potentially useful for assembling 1D nanostructures into functional devices based on crossbar junctions, and complex architectures such as 2D and 3D periodic lattices. We conclude this review with personal perspectives on the directions towards which future research on this new class of nanostructured materials might be directed.

Electrospinning provides a simple and versatile method for generating ultrathin fibers from a rich variety of materials that include polymers, composites, and ceramics. This article presents an overview of this technique, with focus on progress achieved in the last three years. After a brief description of the setups for electrospinning, we choose to concentrate on the mechanisms and theoretical models that have been developed for electrospinning, as well as the ability to control the diameter, morphology, composition, secondary structure, and spatial alignment of electrospun nanofibers. In addition, we highlight some potential applications associated with the remarkable features of electrospun nanofibers. Our discussion is concluded with some personal perspectives on the future directions in which this wonderful technique could be pursued.

Recently a new, large family of two‐dimensional (2D) early transition metal carbides and carbonitrides, called MXenes, was discovered. MXenes are produced by selective etching of the A element from the MAX phases, which are metallically conductive, layered solids connected by strong metallic, ionic, and covalent bonds, such as Ti₂AlC, Ti₃AlC₂, and Ta₄AlC₃. MXenes ­combine the metallic conductivity of transition metal carbides with the hydrophilic nature of their hydroxyl or oxygen terminated surfaces. In essence, they behave as “conductive clays”. This article reviews progress—both ­experimental and theoretical—on their synthesis, structure, properties, intercalation, delamination, and potential applications. MXenes are expected to be good candidates for a host of applications. They have already shown promising performance in electrochemical energy storage systems. A detailed outlook for future research on MXenes is also presented.

Popularization of portable electronics and electric vehicles worldwide stimulates the development of energy storage devices, such as batteries and supercapacitors, toward higher power density and energy density, which significantly depends upon the advancement of new materials used in these devices. Moreover, energy storage materials play a key role in efficient, clean, and versatile use of energy, and are crucial for the exploitation of renewable energy. Therefore, energy storage materials cover a wide range of materials and have been receiving intensive attention from research and development to industrialization. In this Review, firstly a general introduction is given to several typical energy storage systems, including thermal, mechanical, electromagnetic, hydrogen, and electrochemical energy storage. Then the current status of high‐performance hydrogen storage materials for on‐board applications and electrochemical energy storage materials for lithium‐ion batteries and supercapacitors is introduced in detail. The strategies for developing these advanced energy storage materials, including nanostructuring, nano‐/microcombination, hybridization, pore‐structure control, configuration design, surface modification, and composition optimization, are discussed. Finally, the future trends and prospects in the development of advanced energy storage materials are highlighted.

Super‐hydrophobic surfaces, with a water contact angle (CA) greater than 150°, have attracted much interest for both fundamental research and practical applications. Recent studies on lotus and rice leaves reveal that a super‐hydrophobic surface with both a large CA and small sliding angle (α) needs the cooperation of micro‐ and nanostructures, and the arrangement of the microstructures on this surface can influence the way a water droplet tends to move. These results from the natural world provide a guide for constructing artificial super‐hydrophobic surfaces and designing surfaces with controllable wettability. Accordingly, super‐hydrophobic surfaces of polymer nanofibers and differently patterned aligned carbon nanotube (ACNT) films have been fabricated.

BiFeO₃ is perhaps the only material that is both magnetic and a strong ferroelectric at room temperature. As a result, it has had an impact on the field of multiferroics that is comparable to that of yttrium barium copper oxide (YBCO) on superconductors, with hundreds of publications devoted to it in the past few years. In this Review, we try to summarize both the basic physics and unresolved aspects of BiFeO₃ (which are still being discovered with several new phase transitions reported in the past few months) and device applications, which center on spintronics and memory devices that can be addressed both electrically and magnetically.