Lee

A flexible alkaline battery with multiwalled carbon nanotube (MWCNT) enhanced composite electrodes and polyvinyl alcohol (PVA)-poly (acrylic acid) (PAA) copolymer separator has been developed. Purified MWCNTs appear to be the most effective conductive additive, while the flexible copolymer separator not only enhances flexibility but also serves as electrolyte storage.

Better electrode architecture: spherical assemblies of electrochemically active nanocrystals threaded with carbon nanotubes are made using a simple solvation-induced-assembly process. This architecture provides the composites with mechanical robustness, effective ion- and electron-transport pathways, enabling the fabrication of electrodes with high rate, high capacity, and long cycling stability.

Assembly of single layers: Three-dimensional assembly of single-layered MoS₂ is achieved on a large scale via a solution method. The as-prepared tubular architectures have tunable size and mesopores in the shell, which are desirable for applications. As a example, they exhibit excellent lithium storage properties and are highly active for hydrodesulfurization of thiophene resulting from their structural advantages.

By controlling the SWNT-rGO electrode composition and thickness to attain the appropriate porosity and tortuosity, the electroactive surface area is maximized while rapid diffusion of the electrolyte through the electrode is maintained. This leads to an increase in exchange current density between the electrode and electrolyte which results in enhanced thermocell performance.

Outstanding pristine properties of carbon nanotubes and graphene have limited the scope for real-life applications without precise controllability of the material structures and properties. This invited article to celebrate the 25^th anniversary of Advanced Materials reviews the current research status in the chemical modification/doping of carbon nanotubes and graphene and their relevant applications with optimized structures and properties. A broad aspect of specific correlations between chemical modification/doping schemes of the graphitic carbons with their novel tunable material properties is summarized. An overview of the practical benefits from chemical modification/doping, including the controllability of electronic energy level, charge carrier density, surface energy and surface reactivity for diverse advanced applications is presented, namely flexible electronics/optoelectronics, energy conversion/storage, nanocomposites, and environmental remediation, with a particular emphasis on their optimized interfacial structures and properties. Future research direction is also proposed to surpass existing technological bottlenecks and realize idealized graphitic carbon applications.

The current research status in the chemical modification/doping of carbon nanotubes and graphene is reviewed and their relevant applications in diverse areas, such as flexible electronics/optoelectronics, energy conversion/storage, nanocomposites and environmental remediation are discussed. An overview of specific correlations between chemical modification/doping of the graphitic carbons with their tunable material properties is presented, which offers research direction to realize idealized graphitic carbon nanostructures in future advanced applications.

A highly flexible graphene free-standing film with hierarchical structure is prepared by a facile template method. With a porous structure, the film can be easily bent and cut, and forms a composite with another material as a scaffold. The 3D graphene film exhibits excellent rate capability and its capacitance is further improved by forming a composite with polyaniline nanowire arrays. The flexible hierarchical composite proves to be an excellent electrode material for flexible supercapacitors.

Multilayered Si/RGO anode nanostructures, featuring alternating Si nanoparticle (NP) and RGO layers, good mechanical stability, and high electrical conductivity, allow Si NPs to easily expand between RGO layers, thereby leading to high reversible capacity up to 2300 mAh g⁻¹ at 0.05 C (120 mA g⁻¹) and 87% capacity retention (up to 630 mAh g⁻¹) at 10 C after 152 cycles.

A new kind of high-performance asymmetric supercapacitor is designed with pyrolyzed bacterial cellulose (p-BC)-coated MnO₂ as the positive electrode material and nitrogen-doped p-BC as the negative electrode material, via an easy, efficient, large-scale, and green fabrication approach as described by Shu-Hong Yu and co-workers, on page 4746. The optimal asymmetric device possesses an excellent supercapacitive behavior with quite high energy and power density.

Study of flexible nanodielectric materials (FNDMs) with high permittivity is one of the most active academic research areas in advanced functional materials. FNDMs with excellent dielectric properties are demonstrated to show great promise as energy-storage dielectric layers in high-performance capacitors. These materials, in common, consist of nanoscale particles dispersed into a flexible polymer matrix so that both the physical/chemical characteristics of the nanoparticles and the interaction between the nanoparticles and the polymers have crucial effects on the microstructures and final properties. This review first outlines the crucial issues in the nanodielectric field and then focuses on recent remarkable research developments in the fabrication of FNDMs with special constitutents, molecular structures, and microstructures. Possible reasons for several persistent issues are analyzed and the general strategies to realize FNDMs with excellent integral properties are summarized. The review further highlights some exciting examples of these FNDMs for power-energy-storage applications.

Recent progress in the development of flexible nanodielectric materials (FNDMs) with high dielectric permittivity is highlighted. Particular focus is given to increasing the energy density of various FNDMs. Key issuses in the synthesis, structure, and dielectric properties of nanodielectrics are reviewed. Some long-standing problems and topics that warrant further investigation are also addressed.