The structural modification of nanomaterials at the atomic level has the potential to generate tailor-made components with enhanced performance for a variety of tasks. The chemical versatility of graphene has been constantly employed to fabricate multi-functional doped 2D materials with applications encompassing energy storage and electrocatalysis. Despite the many reports on boron- and nitrogen-doped graphenes, the possible synergy that arises from combining these electronically complementary elements has yet to be fully understood and explored. The techniques used for the fabrication of these nanomaterials are reviewed, along with the most recent reports on the benefits of B, N singly doping and co-doping in the electrocatalysis for oxygen reduction reactions and for energy storage in supercapacitors and lithium secondary batteries. The investigation of bulk co-doped materials has intrinsic limitations in fully understanding the real role of heteroatoms in the above applications. Ultimately, the design and creation of substituted monolayers with controlled compositions might hold the key for carbon-based energy-related applications.

Batteries for high temperature applications capable of withstanding over 60 °C are still dominated by primary cells. Conventional rechargeable energy storage technologies which have exceptional performance at ambient temperatures employ volatile electrolytes and soft separators, resulting in catastrophic failure under heat. A composite electrolyte/separator is reported that holds the key to extend the capability of Li-ion batteries to high temperatures. A stoichiometric mixture of hexagonal boron nitride, piperidinium-based ionic liquid, and a lithium salt is formulated, with ionic conductivity reaching 3 mS cm⁻¹, electrochemical stability up to 5 V and extended thermal stability. The composite is used in combination with conventional electrodes and demonstrates to be stable for over 600 cycles at 120 °C, with a total capacity fade of less than 3%. The ease of formulation along with superior thermal and electrochemical stability of this system extends the use of Li-ion chemistries to applications beyond consumer electronics and electric vehicles.

3D CoNi₂S₄-graphene-2D-MoSe₂ (CoNi₂S₄-G-MoSe₂) nanocomposite is designed and prepared using a facile ultrasonication and hydrothermal method for supercapacitor (SC) applications. Because of the novel nanocomposite structures and resultant maximized synergistic effect among ultrathin MoSe₂ nanosheets, highly conductive graphene and CoNi₂S₄ nanoparticles, the electrode exhibits rapid electron and ion transport rate and large electroactive surface area, resulting in its amazing electrochemical properties. The CoNi₂S₄-G-MoSe₂ electrode demonstrates a maximum specific capacitance of 1141 F g⁻¹, with capacitance retention of ≈108% after 2000 cycles at a high charge–discharge current density of 20 A g⁻¹. As to its symmetric device, 109 F g⁻¹ at a scan rate of 5 mV s⁻¹ is exhibited. This pioneering work should be helpful in enhancing the capacitive performance of SC materials by designing nanostructures with efficient synergetic effects.

The emergence of semiconducting transition metal dichalcogenide (TMD) atomic layers has opened up unprecedented opportunities in atomically thin electronics. Yet the scalable growth of TMD layers with large grain sizes and uniformity has remained very challenging. Here is reported a simple, scalable chemical vapor deposition approach for the growth of MoSe₂ layers is reported, in which the nucleation density can be reduced from 10⁵ to 25 nuclei cm⁻², leading to millimeter-scale MoSe₂ single crystals as well as continuous macrocrystalline films with millimeter size grains. The selective growth of monolayers and multilayered MoSe₂ films with well-defined stacking orientation can also be controlled via tuning the growth temperature. In addition, periodic defects, such as nanoscale triangular holes, can be engineered into these layers by controlling the growth conditions. The low density of grain boundaries in the films results in high average mobilities, around ≈42 cm² V⁻¹ s⁻¹, for back-gated MoSe₂ transistors. This generic synthesis approach is also demonstrated for other TMD layers such as millimeter-scale WSe₂ single crystals.

Although a lot of work has been reported on the growth and properties of 2D atomic layered materials, the growth mechanism for these crystals via the chemical vapor deposition method (CVD) has remained elusive. Here, a screw dislocation–driven spiral growth of SnSe₂ crystal flakes via CVD is reported. The polymorph of as-synthesized SnSe₂ crystals is verified as 1T-phase by both experimental characterization and theoretical calculation. The density functional theory study reveals morphology transformation during the growth process while phase-field modeling unravels the screw dislocation propagation to form the pyramid-like structure of SnSe₂. The optical band gap of SnSe₂ crystals relates to an indirect band gap of 1.0 eV. The photodetector devices based on SnSe₂ crystals exhibit high responsivity and ultrafast response time in the microsecond regime.

Batteries have become fundamental building blocks for the mobility of modern society. Continuous development of novel battery chemistries and electrode materials has nourished progress in building better batteries. Simultaneously, novel device form factors and designs with multi-functional components have been proposed, requiring batteries to not only integrate seamlessly to these devices, but to also be a multi-functional component for a multitude of applications. Thus, in the past decade, along with developments in the component materials, the focus has been shifting more and more towards novel fabrication processes, unconventional configurations, and additional functionalities. This work attempts to critically review the developments with respect to emerging electrochemical energy storage configurations, including, amongst others, paintable, transparent, flexible, wire or cable shaped, ultra-thin and ultra-thick configurations, as well as hybrid energy storage-conversion, or graphene-incorporated batteries and supercapacitors. The performance requirements are elaborated together with the advantages, but also the limitations, with respect to established electrochemical energy storage technologies. Finally, challenges in developing novel materials with tailored properties that would allow such configurations, and in designing easier manufacturing techniques that can be widely adopted are considered.

Two-dimensional (2D) atomic layers such as graphene, and metal chalcogenides have recently attracted tremendous attention due to their unique properties and potential applications. Unfortunately, in most cases, the free-standing nanosheets easily re-stack due to their van der Waals forces, and lose the advantages of their separated atomic layer state. Here, a bottom-up approach is developed to build three-dimensional (3D) architectures by 2D nanosheets such as MoS₂ and graphene oxide nanosheets as building blocks, the thin nature of which can be well retained. After simply chemical reduction, the resulting 3D MoS₂-graphene architectures possess high surface area, porous structure, thin walls and high electrical conductivity. Such unique features are favorable for the rapid diffusions of both lithium ions and electrons during lithium storage. As a consequence, MoS₂-graphene electrodes exhibit high reversible capacity of ≈1200 mAh g⁻¹, with very good cycling performance. Moreover, such a simple and low-cost assembly protocol can provide a new pathway for the large-scale production of various functional 3D architectures for energy storage and conversions.

In the pursuit of advanced polymer composites, nanoscale fillers have long been championed as promising candidates for structural reinforcement. Despite progress, questions remain as to how these diminutive fillers influence the distribution of stresses within the matrix and, in turn, influence bulk mechanical properties. The dynamic mechanical behavior of elastomer-impregnated forests of carbon nanotubes (CNTs) has revealed distinct orientation-dependent behavior that sheds light on these complicated interactions. When compressed along the axis of the fillers, the composite will mimic open-cell foams and exhibit strain softening for increasing amplitudes due to the collective Euler buckling of the slender nanotubes. In contrast, the same material will behave similarly to the neat polymer when compressed orthogonal to the alignment direction of the nanotubes. However, in this orientation the material is incapable of achieving the same ultimate compressive strain due to the role that the embedded nanotubes play in augmenting the effective cross-link density of the polymer network. Both of these responses are recoverable, robust, and show little dependency on the diameter and wall-number of the included CNTs. Such observations give insight into the mechanics of polymer/nanoparticle interactions in nanocomposite structures under strain, and the thoughtful control of such coordinated buckling behavior opens the possibility for the development of foam-like materials with large Poisson ratios.

The synthesis and characterization of multifunctional cement and concrete composites filled with hexagonal boron nitride (h-BN) and graphite oxide (GO), is reported and their superior mechanical strength and oil adsorption properties compared to composites devoid of fillers are illustrated. GO is utilized to bridge the cement surfaces while h-BN is used to mechanically reinforce the composites and adsorb the oil. Introduction of these fillers even at low filler weight fractions increases the compressive strength and toughness properties of pristine cement and of porous concrete significantly, while the porous composite concrete illustrates excellent ability for water separation and crude oil adsorption. Experimental results along with theoretical calculations show that such nanoengineered forms of cement based composites would enable the development of novel forms of multifunctional structural materials with a range of environmental applications.

Two-dimensional (2D) atomic layers derived from bulk layered materials are very interesting from both scientific and application viewpoints, as evidenced from the story of graphene. Atomic layers of several such materials such as hexagonal boron nitride (h-BN) and dichalcogenides are examples that complement graphene. The observed unconventional properties of graphene has triggered interest in doping the hexagonal honeycomb lattice of graphene with atoms such as boron (B) and nitrogen (N) to obtain new layered structures. Individual atomic layers containing B, C, and N of various compositions conform to several stable phases in the three-component phase diagram of B–C–N. Additionally, stacking layers built from C and BN allows for the engineering of new van-der-Waals stacked materials with novel properties. In this paper, the synthesis, characterization, and properties of atomically thin layers, containing B, C, and N, as well as vertically assembled graphene/h-BN stacks are reviewed. The electrical, mechanical, and optical properties of graphene, h-BN, and their hybrid structure are also discussed along with the applications of such materials.