Supercapacitors have gained a lot of attention due to their unique features like high power, long cycle life and environment-friendly nature. They act as a link for energy-power difference between a traditional capacitor (having high power) and fuel cells/batteries (having high energy storage). In this perspective, a worldwide research has been reported to address this and rapid progress has been achieved in the advancement of fundamental as well as the applied aspects of supercapacitors. Here, a concise description of technologies and working principles of different materials utilized for supercapacitors has been provided. The main focus has been on materials like carbon-based nanomaterials, metal oxides, conducting polymers and their nanocomposites along with some novel materials like metal-organic frameworks, MXenes, metal nitrides, covalent organic frameworks and black phosphorus. The performance of nanocomposites has been analysed by parameters like energy, capacitance, power, cyclic performance and rate capability. Some of the latest supercapacitors such as electrochromic supercapacitor, battery-supercapacitor hybrid device, electrochemical flow capacitor, alternating current line filtering capacitor, micro-supercapacitor, photo-supercapacitor, thermally chargeable supercapacitor, self-healing supercapacitor, piezoelectric and shape memory supercapacitor have also been discussed. This review covers the up-to-date progress achieved in novel materials for supercapacitor electrodes. The latest fabricated symmetric/asymmetric supercapacitors have also been reported.

Review of supercapacitors: Materials and devices

Supercapacitors (SCs) possess paramount importance and are a promising solution among the class of energy storage devices since they have appreciable features like higher specific power, longer life span, and eco-friendly nature. They replace the difference of energy/power between the high-power traditional capacitors and high energy fuel cells/ batteries. In the current review, comprehensive research on the recent literature of SCs investigates and elucidates with great consideration. The global market analysis, manufacturing firms, challenges, and recent advances present the fundamental, as well as application perspective of SCs. An elaborate analysis of the classifications of SCs, fabrication of different electrode materials from the very beginning of their evolution gives the lucid idea. The evaluation of SC nanocomposites with different parameters such as specific capacitance, energy density, power density, cycling performance, and capacity retention depicts the performance. Detail description of the selection of electrolytes and various synthesis methods of the SCs explains comprehensively. In the end, future scope and challenges mention briefly and consider for the next-generation SC's design and applications. This review provides a reference point on the SCs for researchers and designers working in the field of energy storage devices and applications.

An intuitive review of supercapacitors with recent progress and novel device applications

Any surface immersed in the aqueous reaction mixture used for the preparation of polyaniline becomes coated with a polyaniline film of submicrometre thickness. In this way, various materials can be modified by an overlayer of conducting polymer. The present review illustrates the role of infrared, Raman, and UV-VIS spectroscopies in the studies of polyaniline film growth. Spectroscopic methods are crucial in the evaluation of the performance of polyaniline films alone or in combination with nanoparticles of noble metals. The assessment of film ageing and stability can be followed conveniently by these methods. Carbonization of polyaniline films to nitrogen-containing carbon analogues is also discussed.

Spectroscopy of thin polyaniline films deposited during chemical oxidation of aniline

The explosive progress of electronic devices and communication systems results in the production of undesirable electromagnetic pollution, known as electromagnetic interference. The accumulation of electromagnetic radiation in space results in the malfunction of commercial and military electronic appliances, and it may have a negative impact on human health. Thus, the shielding of undesirable electromagnetic interference has become a serious concern of the modern society, and has been a very perspective field of research and development. This paper provides detailed insight into current trends in the advancement of various polymer-based materials with the effects of electromagnetic interference shielding. First, the theoretical aspects of shielding are outlined. Then, the comprehensive description of the structure, morphology and functionalization of the intrinsic conductive polymers, polymers filled with the different types of inorganic and organic fillers, as well as multifunctional polymer architectures are provided with respect to their conductive, dielectric, magnetic and shielding characteristics.

/pdf/progress-in-polymers-and-polymer-composites-used-as-2frhhzo5n8.pdf

Progress in polymers and polymer composites used as efficient materials for EMI shielding

A nanocomposite of titanium dioxide (TiO2) and polyaniline (PANi) was synthesized by in-situ chemical polymerization using aniline (ANi) monomer and TiCl4 as precursors. SEM pictures show that the nanocomposite was created in the form of long PANi chains decorated with TiO2 nanoparticles. FTIR, Raman and UV-Vis spectra reveal that the PANi component undergoes an electronic structure modification as a result of the TiO2 and PANi interaction. The electrical resistor of the nanocomposite is highly sensitive to oxygen and NH3 gas, accounting for the physical adsorption of these gases. A nanocomposite with around 55% TiO2 shows an oxygen sensitivity of 600–700%, 20–25 times higher than that of neat PANi. The n-p contacts between TiO2 nanoparticles and PANi matrix give rise to variety of shallow donors and acceptor levels in the PANi band gap which enhance the physical adsorption of gas molecules.

https://www.mdpi.com/1424-8220/11/2/1924/pdf

Effect of TiO2 on the Gas Sensing Features of TiO2/PANi Nanocomposites

Polypyrrole (PPy)/Al2O3 nanocomposites were prepared by chemical polymerisation of pyrrole in the presence of Al2O3 nanoparticles using iron trichloride (FeCl3) as an oxidant. The obtained nanocomposites were characterised by Fourier transform infrared spectroscopy, Raman spectroscopy, scanning electron microscopy and thermal gravimetric analysis. Upon exposure to an electromagnetic wave in the X-band ranging from 8 to 12 GHz, PPy/Al2O3 composite was shown to be an effective electromagnetic absorbent. More than 53% of the incident microwave radiation was absorbed after passing through a thick composite coated textile.

Polypyrrole/Al2O3 nanocomposites: preparation, characterisation and electromagnetic shielding properties

Nanocomposites of polyindole (PIn) and TiO2 were prepared by chemical polymerization. The morphology of nanocomposite particles was studied by scanning electron microscopy and transmission electron microscopy. The chemical structure of conducting polymers in nanocomposites was characterized by FTIR and Raman spectra. The thermal analysis showed that all conducting polymers in the nanocomposites were stable at more than 600°C. The corrosion protection of the nanocomposites was investigated.

https://iopscience.iop.org/article/10.1088/1742-6596/187/1/012058/pdf

Synthesis, properties and application of polyindole/TiO2 nanocomposites

An experiment has been carried out to study the formation and characterisation of polyaniline (PANi) nanolayer growth directly on glass and alumina substrate by in situ chemical polymerisation. It has been found that the growth mode of the PANi nanolayer depends on the synthesis time and mechanical agitation. The difference in growth modes results in the form of granular, planar or fibrillar structure and then affects the chemical and electronic structure of the PANi nanolayer. As a result of gas-PANi chain interaction the resistance of the PANi nanolayer is highly sensitive to a variety of gases in environment such as oxygen (oxidising agent), NH3 (reducing agent) and so forth. The feature enables PANi nanolayer made by in situ chemical polymerisation, a promising candidate for gas sensing materials.

In situ chemically polymerised polyaniline nanolayer: characterisation and sensing materials

An experiment has been made in order to study the impact of SWNTs in in-situ chemically polymerized PANi-SWNTs composites It is found that the SWNTs surface plays a role of nucleation sites for PANi growth The presence of SWNTs enhances the degree of polymerization and increase the conductivity (polaron or bipolaron lattice) of PANi When radiated by a near-infrared laser (1064 nm) the dried materials emit strong fluorescent bands in mid-infrared region which are assumed to be the transitions from the π-orbital (highest occupied molecular orbital) to polaron and bipolaron lower levels The bands are speculated to arise from charge transfer interactions between the PANi and SWNTs, which brings new polaron and bipolaron levels into the band gap of PANi The PANi-SWNTs also exhibits an improvement in NH3 gas sensing characterization in comparison to neat SWNTs and PANi The results are interpreted as a modification in the chemical and electronic structure of PANi

Duong Ngoc Huyen

Papers

Polypyrrole/Al2O3 nanocomposites: preparation, characterisation and electromagnetic shielding properties

Synthesis, properties and application of polyindole/TiO2 nanocomposites

In situ chemically polymerised polyaniline nanolayer: characterisation and sensing materials

In-situ Chemically Polymerized PANi-SWNTs Composites: Characterizations and Gas Sensing Feature