Jalal Azadmanjiri

A review on hybrid nanolaminate materials synthesized by deposition techniques for energy storage applications

Nanostructured materials such as nanocomposites and nanolaminates are currently of intense interest in modern materials research. Nanolaminate materials are fully dense, ultra-fine grained solids that exhibit a high concentration of interface defects. They may be developed for engineering applications that take advantage of enhanced mechanical properties or for devices such as energy storage and memory storage capacitors. Nanolaminates can be grown using atom-by-atom deposition techniques that are designed with different stacking sequences and layer thicknesses. The properties of fabricated nanolaminates depend on their compositions and thicknesses. These can be demonstrated within the synthesis process by thickness control of each layer and interfacial chemical reaction between layers. In fact, dielectrics with the formed thin layer have efficient dielectric constant and high insulation characteristics. Dielectric materials with giant dielectric constants can be fabricated as modified single, binary and perovskite oxides. A review of the advantages offered by nanolaminate structures for high performance energy storage devices is presented. Developments of dielectric materials that are formed from a thin layer approach are evaluated. The influence of the interface layer on the dielectric constant of nanolaminate films is assessed from the perspective of conferring a giant dielectric constant and high insulation characteristics. The incorporation of dopants and site-engineering techniques, as well as layer-by-layer structures, which can both be suitable for improving dielectric properties of dielectric nanolaminates, is detailed. Finally, the current status and development of artificial dielectric materials for high performance energy storage devices formed by dielectric nanolaminates are presented.

Development of surface nano-crystallization in alloys by Surface Mechanical Attrition Treatment (SMAT)

Nanometer-sized grain structures that exhibit a large number of grain boundaries on the surface of a bulk material demonstrate excellent properties relative to their coarse-grained (CG) equivalents. Surface modification using surface mechanical attrition treatment (SMAT) is an option that cab be used to tailor the corrosion, tribological, mechanical, and chemical reaction properties of a surface. SMAT is an effective route to create the nanostructured surface layer. The SMAT process has unique advantages compared with the other coating and deposition techniques for surface nanocrystallization. For example, SMAT does not alter the chemical composition of the nanocrystalline surface layer in the matrix. In addition, SMAT has been demonstrated to activate the material surface layer by surface modification and enhance the atomic diffusivity. This article presents a review of the advantages offered by the SMAT technique for the creation of high performance surface layers. The influence of the created nanocrystalline layer on mechanical, physical, and chemical properties is assessed. Developments and the current status of the surface nanolayer that are formed are evaluated from a physical approach. Finally, prospects for the future development of grain refinement on the surface of a material matrix and potential applications are presented.

Two- and three-dimensional graphene-based hybrid composites for advanced energy storage and conversion devices

Due to its superior electronic, thermal, and mechanical properties, graphene is considered to be the most promising candidate for constructing energy storage and conversion devices. One important way to exploit the potential of graphene is to create graphene composites with other functional materials. Graphene-based hybrid composites (GHCs) have been fabricated by incorporating inorganic and/or organic species into graphene through covalent and/or noncovalent interactions. Different methods of fabrication resulted in different properties of GHCs. So far, GHCs have found wide applications in various sectors. In this article, recent progress and achievements in the preparation of two- and three-dimensional GHCs are reviewed, followed by detailed discussions on their physical, chemical, and mechanical properties. The article then focuses on the detailed applications of GHCs in energy storage and conversion devices.

Nanolaminated composite materials: structure, interface role and applications

This article is a review on the nanolaminate composite materials from a materials science perspective. In fact, nanolaminate composite materials are a category of two-dimensional nanomaterials in the fields of chemistry, materials science and condensed matter physics. Miniaturization of materials to the nanometer scale is improving remarkably in science and technology. Nanolaminates constitute a unique class of nanomaterials that illustrate fascinating mechanical, physical, chemical and electrical properties and these attributes are increasingly being prospected for promising applications. Nanolaminates can typically be developed using bottom-up techniques that are designed with various stacking series along with layer thicknesses. The particular properties of fabricated nanolaminates can be determined by their arrangements, compositions and thicknesses. The properties can be established during the fabrication process by size control of each coating layer and interfacial chemical reactions between layers. Hence, fundamental understanding of nanoscale layered-engineering during the creation of a nanolaminate structure enables tailoring of the overall performance of these composite materials. This work demonstrates the bottom-up physical and chemical approaches for the fabrication of nanolaminates. The influence of the interface layer in the nanolaminate composite materials is considered from the viewpoint of conferring high performance characteristics. The desirable physical attributes will be pursued by incorporation of dopants and site-engineering techniques on various materials that would improve the nanolaminate properties. The final section concludes with an outlook on future directions in this technological field.

2D layered organic–inorganic heterostructures for clean energy applications

The recent high interest and the fast development of heterostructures of two-dimensional (2D) layered materials are driven by their unique properties and many potential applications. One of the advantages of 2D layered nanostructures is their attractive physical, chemical and mechanical properties that could be designed and tuned by manipulating their composition and thickness at the atomic or molecular level during the synthesis process. This review firstly introduces several versatile chemical approaches for the bottom-up fabrication of 2D layered organic–inorganic hybrid materials. A few types of nanolayered organic–inorganic materials and their tunable properties are then presented and discussed from the view of having high-performance characteristics. The chemical attributes that would enhance the properties of nanolayered organic–inorganic materials are also assessed. This article then focuses on the applications of nanolayered organic–inorganic hybrid materials in clean energy research such as batteries, supercapacitors, water splitting, perovskite solar cells and thermoelectric devices. The final section discusses current challenges and future directions of nanolayered organic–inorganic hybrid materials.

Graphene-supported 2D transition metal oxide heterostructures

Heterostructures of two-dimensional (2D) nanomaterials such as graphene/transition metal oxide (TMO) have recently attracted great interest due to their unique structures and superior properties that none of the individual conventional 2D nanomaterials could have. These unusual properties are due to alteration of the Fermi energy position, density of states, and work function of those heterostructures rather than their chemical components. The physical and quantum properties, the interfacial layer and the synergistic effect of each component in 2D heterostructures lead to the generation of new behavior and properties. In this review article, we are focusing on the recent progress in studying the characteristics and properties of 2D graphene/TMO heterostructures, and their significant applications in advanced energy storage and conversion devices. In this context, we firstly introduce bottom-up wet chemical approaches for the synthesis of 2D graphene/TMO heterostructures. The electron transfer, bonding chemistry and defects at the interface of these heterostructures are then discussed. Thirdly, the tunable properties of 2D graphene/TMO heterostructures and their applications in advanced energy storage and conversion devices are presented. The final section discusses the challenges and future prospects of 2D graphene/TMO heterostructures.