Conducting Polymers:
After world war two whole worlds focused on polymers development due to easily and excess of raw materials availability. Lot of polymers was developed in every field of life and also researcher focused on polymer used as electrodes in Super capacitors due to low cost and easily availability. Also conducting polymers produce good results such as high conductivity, conductance and equivalent resistance as compared to carbon materials.
Conducting polymers show big issue of stability due to
charge discharge cycles. An organic polymer class with the ability to conduct
electricity is known as conducting polymers. Conducting polymers, as opposed to
conventional semiconductors and metals, are lightweight, flexible, and easily
manufactured into thin films or various geometries. (D.-W. Wang et al., 2009).
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Figure 1.11 Schematic diagram of conducting polymers |
Electronics is one of the industries where conducting
polymers have the most potential. They have demonstrated potential for usage in
flexible and stretchable electronics and have been employed as the active
material in electronic devices such as transistors, diodes, and light-emitting
diodes (LEDs). They are also being researched for application in fuel cells and
other energy storage and conversion technology (Awuzie, 2017).
Due to its distinctive characteristics, zinc sulphide (ZnS)
is an important semiconductor material with lot of application. ZnS is a
desirable option for many applications due to its abundant availability and low
semiconductor material. The structural characteristics of ZnS are also impacted
by Al doping. Compared to pure ZnS, al-doped ZnS has a larger lattice constant,
which may have an impact on its mechanical and thermal properties. Al-doped ZnS
crystal structure is dependent on synthesis technique and doping concentration
(Y. Zhang et al., 2019).
Quantum dots frequently use ZnS as their host material. It
is possible to make quantum dots with distinct optical and electrical
properties by doping ZnS with other elements, such cadmium or manganese.
Numerous applications, such as biological imaging and sensing, solar cells, and
optoelectronic devices, can make use of these quantum dots (Bauer, Bravyi,
Motta, & Chan, 2020).
Humanity has faced an escalating trend in pollution and
depleting energy supplies over the previous few decades. These issues shift our
focus to energy storable technologies with greater energy and power densities
in order to carry out our enticing plans. To address the world's energy needs,
research has focused on creating energy storage and conversion technologies,
such as batteries, Supercapacitors, and catalysis.
Supercapacitors (SCs), which offer outstanding power
density, prolonged cyclic stability and good pulse rate during charging and
discharging, is one of the most efficient energy storage technologies. (Z. Yang
et al..2011).
Significant light-matter interactions were also seen in ZnS nanowires, making them appealing for optoelectronic applications.. Al-doped ZnS has been researched for its photocatalytic abilities, particularly for the solar-powered hydrogen generation of water. Al-doped ZnS is a promising material for applications involving sustainable energy because it has been discovered to have increased photocatalytic activity when compared to pure ZnS (Delbari et al., 2021).
Because of its significant energy storage benefits (Xie & Du, 2012), ZnS is one of the transitions metal sulphide that is most explored as an electrode material and is a good option for use in Supercapacitors (Javed et al., 2016).
Single step electrochemical deposition process is required for preparation of ZnS electrodes, where the growth and morphology of ZnS Nano crystalline particles could be manipulated by altering the scanning speed. This preparation technique is easy controllable and cost-effective. Moreover, it is time-efficient and does not require excessive energy consumption or result in high costs.
By setting the scanning rate and microstructure during the
electrochemical deposition process and we get excellent energy storage
performance (Rao, Thomas, & Kulkarni, 2007).
The study aimed to investigate the effect of changing the
scanning rate during cyclic voltammetry (CV) electrochemical deposition process
on the microstructure and energy storage properties of the ZnS/NF electrode
material.
The researchers used various techniques to fully
characterize the prepared electrode materials, including microscopy and
electrochemical measurements. The results showed that the electrode materials
show several microstructures exhibited different energy storage quantities.
Specifically, the value 1827.5 F/g achieved was maximum mass
specific capacity at a current density of 15 A g−1, while the maximum area
specific capacity was 354.5 mF cm−2 at a current density of 3 mA cm−2.
This indicates that the ZnS/NF electrode
material has good cycling stability and can be suitable for long-term energy
storage applications (G. Wang et al., 2012).
Overall, the study suggests that the prepared ZnS electrode
material for asymmetric Supercapacitors can be a promising candidate as
electrode material, which are energy storage devices that can provide long
cyclic life and high power density (Wei et al., 2016).
Despite ZnS possessing unique electronic properties, its exceptional electrochemical energy storage behavior still remains underexplored. Moreover, the value of specific capacitance remained low for hybrid electrode materials and resulting in poor rate performance.
The uniform size and distribution of ZnS nanoparticles saved from the polarization phenomenon caused by uneven electrode particles during the later stage of discharge. With the combined benefits of its structure, the ZnS nanoparticles electrode shows an exceptional value of specific capacitance of 824 A g−1.
The uniform size of the ZnS nanoparticles confirms their
enormous potential for applications as a top candidate for high-performance
energy storage devices. This letter describes a successful synthesis of ZnS
nanoparticles with a consistent particle size of about 30 nm, which will
improve the performance of ZnS electrodes (Y. Yang et al., 2021).
