Interfacial Engineering of Flexible Transparent Conducting Films

One-dimensional (1D) carbon nanotubes (CNTs) and silver nanowires (AgNWs) have been used as replacements for brittle indium tin oxide (ITO) in the fabrication of transparent conducting films (TCFs), which can be used in opto-electronic devices such as screen panels, solar cell panels, and organic light-emitting diodes. This chapter describes a fabrication method of high-performance TCFs by solution processing of single-walled CNTs (SWCNTs) and AgNWs. Highly uniform TCFs with SWCNTs and AgNW inks were fabricated using spray deposition. Their performance was modulated by interfacial engineering such as overcoating with silane compound for densification of SWCNT networks and chemical or photothermal welding of SWCNT networks on thermoplastic substrates. Moreover, the hybridization of SWCNTs, AgNWs, and graphene oxide nanosheets is a promising approach to mitigate their drawbacks via p-type doping, electrical stabilization, or interfacial stabilization on plastic substrates. The rational control of 1D material networks can provide a good opportunity to fabricate high-performance TCFs for flexible opto-electronic devices

Chemically Exfoliated Graphene Nanosheets for Flexible Electrode Applications

Graphene oxide (GO), produced by oxidation of graphite powder and exfoliation, is intensively utilized in electrodes, templates for hybrid materials, interfacial modifiers, three-dimensional structures, and so on, with its performance as an electrode material being determined by its chemical and structural states. This chapter describes the fabrication method of GO nanosheets from graphite oxide powder and their stable dispersion after reduction and applications in devices. Rheologically driven exfoliation and unusual acoustic cavitation methods were applied to produce large and less defective GO nanosheets. As a dispersion strategy of reduced GO (RGO) in solution, TiO2 precursor, cation-π interaction, silanol groups were introduced. Moreover, supramolecular chemistry, for example, quadruple hydrogen bonding moieties, was applied to solve the dispersion of highly concentrated RGO pastes. As potential applications of GO and RGO, we described GO as a p-type dopant and interfacial modifier as well as energy storage electrodes, IR sensors, and emitters. The judicious use of chemically exfoliated graphene can open new applications as a flexible electrode

Electronic Textiles Based on Highly Conducting Poly(vinyl alcohol)/Carbon Nanotube/Silver Nanobelt Hybrid Fibers

Highly stable conducting fibers have attracted significant attention in electronic textile (e-textile) applications. Here, we fabricate highly conducting poly(vinyl alcohol) (PVA) nanocomposite fibers with high thermal and chemical stability based on silver nanobelt (AgNB)/multiwalled carbon nanotube (MWCNT) hybrid materials as conducting fillers. At 20 vol % AgNB/MWCNT, the electrical conductivity of the fiber dramatically increased (similar to 533 times) from 3 up to 1600 S/cm after thermal treatment at 300 degrees C for 5 min. Moreover, PVA/AgNB/MWCNT fiber resists the harsh conditions of good solvents for PVA as well as high temperatures over the melting point of PVA, whereas pure PVA fiber is unstable in these environments. The significantly enhanced electrical conductivity and chemical stability can be realized through the post-thermal curing process, which is attributed to the coalescence between adjacent AgNBs and additional intensive cross-linking of PVA. These remarkable characteristics make our conducting fibers suitable for applications in e-textiles such as water leakage detectors and wearable heaters. In particular, heating behavior of e-textiles by Joule heating can accelerate the desorption of physically trapped moisture from the fiber surface, resulting in the fully reversible operation of water leakage monitoring. This smart e-textile sensor based on highly stable and conductive composite fibers will pave the way for diverse e-textile applications

Ribbon-like activated carbon with a multi-structure for supercapacitors

Ribbon-like activated carbon (RAC) has been successfully developed by a two-step activation process based on alkali activation and an electrochemical activation route. The multi-structure of the RAC features a porous graphitic structure with the coexistence of micropores and graphitic structures, mainly originating from the loose packing of the graphite sheets as a result of the degree of graphitization controlled by the carbonization conditions. RAC provides the tremendous benefits of excellent cycle life, high power (3.2 kW kg(-1)), and high energy density (43.5 W h kg(-1)) for electric double-layer capacitors, because of its graphitic architecture comprised of micropores and ring-shaped crystalline structures. In addition to investigating the improved electrochemical performance, we observed an interesting feature of the RAC: the obtained RAC has a high structural stability as shown by ex situ high-resolution transmission electron microscopy (HR-TEM). These extraordinary results are attributed to the unique structure of RAC.

Carbon shell-coated mackinawite FeS platelets as anode materials for high-performance sodium-ion batteries

Mackinawite iron sulfide (M-FeS), a rarely reported conversion-type anode material, undergoes repeated volume changes during the charge–discharge process, which eventually induces fast electrochemical degradation. However, commonly used strategies to mitigate volume changes using hybridization with carbon materials require high temperatures above 500 °C, which is limited for M-FeS due to its low thermal stability. Here, a novel and facile strategy to hybridize M-FeS with a carbon material using a one-step hydrothermal method under low-temperature conditions (125 °C) is reported. Carbon dots with functional groups were served as nucleation sites, and hybridized with M-FeS. The hybrid material (M-FeS@C) comprised micron-sized M-FeS particles wrapped with a carbon shell and exhibited improved structural stability during the charge–discharge process when tested for sodium-ion storage; stable cycle performance was achieved for 500 cycles delivering a capacity of 372 mAh g−1 at a current density of 1 A g−1. Moreover, when Ox-SWCNTs were also used as a conductive agent, a three-dimensional (3D) conductive network that provides electrical pathways was formed and preserved. The synergic effects of the carbon shell and CNT conductive agent (M-FeS@C+CNT) maximized the structural stability and the electrical conduction path, resulting in a capacity of 336 mAh g−1 at a high current density of 10 A g−1 and a capacity of 360 mAh g−1 for 860 cycles at 1 A g−1. © 2023 Elsevier B.V.11Nsciescopu