In situ doping of PANI nanocomposites by gold nanoparticles for high-performance electrochemical energy storage: ARTICLE

Tuneable Plasmonic Resonances Of A Dynamic Thin Film Of Ultrasmall Nanocrystals Modified In the Anti-Galvanic Reduction Process

Ultrasmall gold nanoparticles (NPs) have revolutionized nanotechnology as they are an excellent starting substrate for the synthesis of organic-inorganic hybrid materials with photonic or energy conversion applications, often with a responsive nature. However, ultrasmall NPs do not sustain plasmonic resonances, preventing their use in plasmon-related applications. In the presented work, we show a method of chemical modification of ultrasmall gold nanoparticles in order to fabricate dynamically controlled plasmonic thin films. For this purpose, we used the Anti-Galvanic Reduction process (AGR) to modify the surface of small gold nanoparticles, inducing plasmonic properties without notable size increases. Au@Ag NPs are then modified with liquid crystal-like organic ligands. The obtained NPs can assemble into densely packed films with long-range order and temperature-dependent structural properties. Namely, we detect two, fully reversible phase transitions between the hexagonal and cubic symmetries. The combination of AGR and organic surface modifications enabled us to demonstrate the possibility of managing plasmonic properties in the thin film of ~2 nm diameter metallic NPs.

An All-Solid-State Flexible Supercapacitor Based on MXene/MSA Ionogel and Polyaniline Electrode with Wide Temperature Range, High Stability, and High Energy Density

In this study, an ionogel electrolyte (PAIM-X) consisting of 1-vinyl-3-methylimidazole bis (trifluoromethyl sulfonyl) imide ([VMIM][TFSI]), Polyacrylamide (PAAm), and MXene were prepared. The conductivity of PAIM-X and integral area of the voltammetric curve of the supercapacitor (PAIMSC) were improved by adding MXene. The addition of [VMIM][TFSI] enhanced the conductivity and applicable temperature of the ionogel electrolyte. At 90 °C, the conductivity of PAIM-4 can reach 36.4 mS/cm. In addition, spherical polyaniline with good electrochemical properties was synthesized and coated on graphite paper as an active substance. An all-solid-state supercapacitor was composed of PAIM-4, polyaniline electrode with 1.2 V potential window, pseudo-capacitors and high quality capacitors. The solvent 1-ethyl-3-methylimidazolium bis (trifluoromethyl sulfonyl imide) ([EMIM][TFSI]) and methanesulfonic acid (MSA) were introduced into the ionogel to promote the redox reaction of polyaniline (PANI). The mass specific capacitance of PAIMSC was 204.6 F/g and its energy density could reach 40.92 Wh/kg, which shows great potential for practical application at high temperature. The device had good rate performance and cycle performance, and its capacitance retention rate was still 91.56% after 10,000 cycles. In addition, the supercapacitor can work within the temperature range of -20 °C to 90 °C. These excellent electrochemical properties indicate that PAAm/IL/Mxene-X has broad application space and prospect.

Synthesis and Conductivity Studies of Poly(Methyl Methacrylate) (PMMA) by Co-Polymerization and Blending with Polyaniline (PANi)

Poly(methyl methacrylate) (PMMA) is a lightweight insulating polymer that possesses good mechanical stability. On the other hand, polyaniline (PANi) is one of the most favorable conducting materials to be used, as it is easily synthesized, cost-effective, and has good conductivity. However, most organic solvents have restricted potential applications due to poor mechanical properties and dispersibility. Compared to PANi, PMMA has more outstanding physical and chemical properties, such as good dimensional stability and better molecular interactions between the monomers. To date, many research studies have focused on incorporating PANi into PMMA. In this review, the properties and suitability of PANi as a conducting material are briefly reviewed. The major parts of this paper reviewed different approaches to incorporating PANi into PMMA, as well as evaluating the modifications to improve its conductivity. Finally, the polymerization condition to prepare PMMA/PANi copolymer to improve its conductivity is also discussed.

A Novel Approach for Effective Alteration of Morphological Features of Polyaniline through Interfacial Polymerization for Versatile Applications

Morphological characteristics of any nanomaterial are critical in defining its properties. In this context, a method to control morphological parameters of polyaniline (PANI) has been investigated by producing its composite with gold nanoparticles (AuNPs). Herein, we report for the first time the successful control on the physical/chemical properties of PANI composites synthesized via interfacial polymerization through functionalization of its AuNP composite component with citrate, ascorbate, glutathione (GSH), and cetyl trimethyl ammonium bromide (CTAB). A significant difference in the polymerization pattern, morphologies, and electrical properties was recognized in these composites according to the functionality of the modified AuNPs. The obtained composites of AuNPs/PANI exhibited highly diverse morphologies (e.g., nodule, hollow hemisphere, flake, and spider-web galaxy type) and electrical characteristics according to functionalization. Hence, this study is expected to offer better insight into control of the polymerization pattern of AuNP/PANI composites and their associated properties.

Nanocellulose-Based Conductive Membranes for Free-Standing Supercapacitors: A Review

There is currently strong demand for the development of advanced energy storage devices with inexpensive, flexibility, lightweight, and eco-friendly materials. Cellulose is considered as a suitable material that has the potential to meet the requirements of the advanced energy storage devices. Specifically, nanocellulose has been shown to be an environmentally friendly material that has low density and high specific strength, Young's modulus, and surface-to-volume ratio compared to synthetic materials. Furthermore, it can be isolated from a variety of plants through several simple and rapid methods. Cellulose-based conductive composite membranes can be assembled into supercapacitors to achieve free-standing, lightweight, and flexible energy storage devices. Therefore, they have attracted extensive research interest for the development of small-size wearable devices, implantable sensors, and smart skin. Various conductive materials can be loaded onto nanocellulose substrates to endow or enhance the electrochemical performance of supercapacitors by taking advantage of the high loading capacity of nanocellulose membranes for brittle conductive materials. Several factors can impact the electronic performance of a nanocellulose-based supercapacitor, such as the methods of loading conductive materials and the types of conductive materials, as will be discussed in this review.

Toward fiber-, paper-, and foam-based flexible solid-state supercapacitors: electrode materials and device designs

Flexible solid-state supercapacitors possess promising safety performance and intrinsic fast charging-discharging properties, enabling them to accomplish the requirements of lightweight and multifunctional wearable electronics that have recently become fairly popular. Because electrode materials are the core component of flexible solid-state supercapacitors, we exhaustively review the recent investigations involving electrode materials that have used carbons, metal oxides, and conductive polymers. The principles and methods of optimizing and fabricating electrodes for use in flexible supercapacitors are discussed through a comprehensive analysis of the literature. In addition, we focused on three types of flexible solid-state supercapacitors (fiber-, paper-, and porous foam-based structures) to satisfy the requirements of flexible electronic devices. Further, we summarize the practical applications of flexible solid-state supercapacitors, including energy conversion/collection devices and energy storage/detection devices. Finally, we provide the developmental direction for flexible solid-state supercapacitors in the future.

Synthesis of ultra-small gold nanoparticles decorated onto NiO nanobelts and their high electrochemical performance

Ultra-small gold nanoparticles are decorated onto NiO nanobelts using HAuCl₄ and Ni(OH)₂ nanobelts as precursors via a one-step thermal treatment; the effect of the gold content on the structure and electrochemical performance was investigated.

MoO2/Mo2N hybrid nanobelts doped with gold nanoparticles and their enhanced supercapacitive behavior

AuNPMoON-nanobelts with a width of 200 nm and an Au content of 1.08 wt% show a capacitance of 348 F g⁻¹.