Studies on ionic transport and immittance response of carboxymethyl cellulose/polyvinyl alcohol-based solid biopolymer electrolytes and its application

Polymer electrolytes (PEs) have been attracting attention owing to their wide application in areas of energy storage devices. Extensive research has been focusing on the application of petroleum-based polymers which give drawbacks including high costs, petroleum resources depletion and environmental problems. Thus, this present research has been carried out on biopolymers comprising of carboxymethyl cellulose (CMC)–polyvinyl alcohol (PVA) polymer blend as host which is prepared via the solution casting technique. The incorporation of ionic dopant (NH4NO3) followed by plasticizer, namely ethylene carbonate (EC) into the CMC–PVA also known as solid biopolymer electrolytes (SBEs) was investigated for the enhancement of the structural, optical and thermal properties via Fourier transform infrared (FTIR) spectroscopy, x-ray diffraction (XRD) spectroscopy, scanning electron microscopy (SEM), thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). This enhancement is important because it could influence the ionic and transport conduction properties of the SBEs that is measured by electrical impedance spectroscopy (IS). The highest conducting SBEs samples were fabricated in an electrical double layer capacitor (EDLC) where its performance was assessed via cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The complexation at the active functional group of C–O–C, –OH and –COO- is believed to influence the crystalline nature where the SBEs became more amorphous upon the addition of the NH4NO3 and EC. Morphology analysis showed that the developed samples have no phase segregation that is also due to the occurrence of complexation in the SBEs system. All SBEs samples were found to be thermally stable up to 300 °C and the ionic conductivity had increased to 1.70 10-3 S/cm with the addition of 30 wt. % NH4NO3 and further increased to 3.92 10-3 S/cm when added with 6 wt. % EC. Based on IR-deconvolution approaches, ionic transport elucidated that number of ions (η), ions mobility (μ) and diffusion coefficient (D) governed the ionic conductivity. The highest conducting samples both from NH4NO3 and EC were found to be stable up to 1.73 V and 1.89 V, respectively based on their electrochemical stability (potential windows). The plasticized SBEs demonstrated better cycling stabilities than un-plasticized SBEs at higher current density, 0.339 mA/cm2. As a result, the plasticized system exhibited higher specific capacitance, energy and power density. Therefore, the present research revealed the possibility of CMC–PVA as an electrolyte system by demonstrating favorable electrochemical properties in an EDLC practical application

Functionalization of carbon and graphene quantum dots

In recent years, quantum dots (QDs) have been widely explored in the field of optoelectronics due to their exceptional physicochemical properties, including chemical stability, size-dependent optoelectronic properties (e.g., bandgap, and energy levels), high surface area, and mechanical flexibility. Furthermore, the QDs are biocompatible and environmentally friendly materials, which have garnered worldwide interests for use as fluorescent probes in bioimaging. This chapter aims to explain the recent findings on this growing topic and to disseminate critical insights, which would shed light onto the deployment of QDs-related technology, including carbon quantum dots and graphene quantum dots (GQDs) from fundamental research works and the applied sciences domain. Several QDs synthesis approaches and physicochemical property characterizations are explained from the perspectives of experimental and theoretical frameworks. The current trends of research, which would predict challenges, prospective candidates of precursors, fabrication technology and targeted size of the GQDs, are also discussed

Effect of C3H4O3 on band gap narrowing of proton conductive hybrid polymer electrolyte

In the present work, hybrid polymer electrolyte based on carboxymethyl cellulose-polyvinyl alcohol-ammonium nitrate-ethylene carbonate (CMC–PVA–NH4NO3–C3H4O3) become the promising materials that has demonstrated outstanding physical properties as an electrolytes system in solar cell. In the frame of solar cell progress, the electrical conductivity and optical bandgap of polymer electrolytes are equally explored. The characterization is carried out via electrical impedance spectroscopy (EIS) and ultraviolet visible-near infrared (UV-VIS-NIR) spectroscopy. An equivalent circuit of parallel combination, bulk resistance (Rb), and constant phase element (CPE) is obtained from transparent conductive film, CMC–PVA–NH4NO3–C3H4O3. The optimum ionic conductivity is accomplished at 3.92 × 10−3 S cm-1 for sample containing with 6 wt.% of C3H4O3. The absorption spectra are evaluated in the wavelength ranging from 200 to 1100 nm. Theoretical analysis reveals that the addition of 6 wt. % EC is initiating the band gap narrowing from 4.96 to 4.88 eV. The results show that the present developed materials-based polymer electrolytes have great potential for solar energy devices

An investigation on the abnormal trend of the conductivity properties of CMC/PVA-doped NH4Cl-based solid biopolymer electrolyte system

The present work was carried out to investigate the abnormal trend of electrochemical properties of solid biopolymer electrolytes (SBEs) system-based carboxymethyl cellulose (CMC) blended with polyvinyl alcohol (PVA)-doped NH4Cl. The SBEs system was prepared via solution casting technique and analyzed through Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and electrical impedance spectroscopy (EIS). Complexation was observed with the changes of peaks at 1065 cm−1, 1598 cm−1, 2912 cm−1, and 3396 cm−1 that corresponds to C–O–C, C=O of COO− stretching, C–H stretching, and O–H stretching, respectively, of CMC/PVA blend system upon the addition of NH4Cl. The decrease of the amorphousness and the increase of weight loss demonstrated the abnormal observation of the ionic conductivity when (1–5 wt%) NH4Cl was added in the SBEs system which was lower than the un-doped SBEs system. It was also observed that the highest ionic conductivity at 8.86 × 10−5 Scm−1 was achieved by the sample containing 6 wt% of NH4Cl. The temperature dependence of the SBEs system is found to be governed by the Arrhenius rule. Through the IR deconvolution technique, the conductivity of CMC/PVA-NH4Cl SBEs system was shown to be primarily influenced by the ionic mobility and diffusion coefficient of the ions

Irregularities trend in electrical conductivity of CMC/PVA-NH4Cl based solid biopolymer electrolytes

n this present work, solid biopolymer electrolytes (SBEs) system consists of the blended polymer namely carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) doped ammonium chloride (NH4Cl) at different composition from 0 to 10 wt. % were successfully prepared by using casting technique. The electrical conductivity of solid biopolymer electrolytes (SBEs) system was investigated by using Electrical Impedance Spectroscopy (EIS). Electrical study shows the highest ionic conductivity in room temperature (303 K) was achieved at 8.86 × 10−5 Scm−1 for sample containing 6 wt. % of NH4Cl. The present system shown unexpected drop after different amount of NH4Cl (1-5 wt. %) were added into the CMC/PVA and its might attributed to the factor of composition of dopant. All SBEs systems were found to be obeys Arrhenius behaviour where the plots show close to unity (R2∼1) and thermally activated

Ionic conductiviy of Alginate-NH4Cl polymer electrolyte

This study aims to produce a solid biopolymer electrolyte (SBE) by doping ammonium chloride (NH4Cl) into alginate. Solution casting was used to prepare the alginate–NH4Cl SBE system. Electrical impedance spectroscopy was performed to analyze the electrical properties of the SBE under the applied frequency range of 50 Hz–1 MHz. The incorporation of 8 wt.% NH4Cl enhances the ionic conductivity of the SBE up to 3.18 × 10-7 S/cm at ambient room temperature. Fourier transform infrared spectroscopy shows that complexation occurs between the hydroxyl (-OH), carboxylate (COO-) and ether linkage (C-O-C) functional groups due to the formation of inter- and intra-molecular hydrogen bonds between the biopolymer and the ionic dopant. The dielectric constant and dielectric loss increase with increasing dopant composition, thereby increasing the number of charge carriers and ionic mobility

Involvement of ethylene carbonate on the enhancement H+ carriers in structural and ionic conduction performance on alginate bio-based polymer electrolytes

This study investigates the structural and ionic conduction performance with the involvement of ethylene carbonate (EC) in a bio-based polymer electrolytes (BBPEs) system, based on alginate doped glycolic acid (GA). The solution casting technique was used to successfully prepare the BBPEs which were characterized with various approaches to evaluate their ionic conduction performance. It was revealed that at ambient temperature, an optimum ionic conductivity of 9.06 × 10−4 S cm−1 was achieved after the addition of 6 wt% EC, with an observed improvement of the amorphous phase and thermal stability. The enhancement of ionic conduction properties is believed to be due to the protonation (H+) enhancement, as proven by FTIR and TNM studies. The findings show that the developed alginate-GA-EC is a promising candidate for use as electrolytes in electrochemical devices that are based on H+ carriers

Organic materials as polymer electrolytes for supercapacitor application

Supercapacitors inevitably attract much attention among the scientific community and the general public since they combine the desirable characteristics of batteries and capacitors. The successful development of environmentally friendly supercapacitors is possible thanks to the organic materials obtained from renewable sources that are considered viable alternative materials for a safer and higher energy polymer electrolytes (PE) system. These organic polymer electrolytes (OPEs) are generally materials consisting of carbon and other atoms, such as oxygen, nitrogen, and halogen. This system is supramolecular in nature and produces high ionic conductivity when doped with ions. There is a myriad of future supercapacitor applications, including their use as supplementary energy sources in the electric grid, electric and microhybrid vehicles, and cell phone base stations. This chapter specifically discusses the recent progress made in the application of OPEs, their performance, challenges, and future directions in the context of supercapacitors

Studies on the ions transportation behavior of alginate doped with H+ carrier-based polymer electrolytes

In the present work, amorphous bio-based polymer electrolytes (BBPEs) using alginate polymer as a matrix host and doped with varying amounts of ammonium iodide (NH4I) have been developed via the solution casting technique. The physicochemical properties of alginate-NH4I BBPEs were evaluated by using X-Ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), electrical impedance spectroscopy (EIS), and transference number measurement (TNM). The BBPEs film containing 25 wt % of NH4I possessed the highest ionic conductivity of 1.29 × 10−4 S cm−1, the highest amorphous phase, and good thermal stability of up to 234 °C. Based on the Nyquist fitting approaches, the ionic conductivity of the BBPEs was primarily influenced by the ion transportation, which was due to the interplay of segmental motion between the alginate and NH4I, and also the H+ hopping mechanism, as shown by FTIR. The proton transference number (tH+ = 0.41) suggests that alginate BBPEs are promising materials in electrochemical device applications

Electrical study on Carboxymethyl Cellulose-Polyvinyl alcohol based bio-polymer blend electrolytes

The present work deals with the formulation of bio-materials namely carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) for bio-polymer blend electrolytes (BBEs) system which was successfully carried out with different ratio of polymer blend. The biopolymer blend was prepared via economical & classical technique that is solution casting technique and was characterized by using impedance spectroscopy (EIS). The ionic conductivity was achieved to optimum value 9.12 x 10-6 S/cm at room temperature for sample containing ratio 80:20 of CMC:PVA. The highest conducting sample was found to obey the Arrhenius behaviour with a function of temperature. The electrical properties were analyzed using complex permittivity ε* and complex electrical modulus M* for BBEs system and it shows the non-Debye characteristics where no single relaxation time has observed