MoS2 nanoflower decorated bio-derived chitosan nanocomposites for sustainable energy storage: Structural, optical and electrochemical studies.

Bio-derived chitosan-molybdenum di sulfide (Cs-MoS2) nanocomposites are prepared by a simple and economical aqueous casting method with varying concentrations of MoS2. The structural, surface morphological, optical, and electrochemical properties of the nanocomposites were studied. FTIR analysis reveals the strong interaction between Cs and MoS2. FESEM micrograph showed an increment of the surface roughness due to the incorporation of MoS2 layers into Cs. The surface wettability of the nanocomposites was found to be decreased from 73° to 33° due to the incorporation of MoS2 into the chitosan. UV-vis spectroscopy study demonstrates a reduction of optical bandgap from 4.29 to 3.44 eV as the nanofiller, MoS2, introduces localized states within the forbidden energy bandgap. The incorporation of MoS2 was found to increase the specific capacitance of Cs from 421 mFg-1 to 1589 mFg-1 at a current density of 100 µAg-1. The EIS analysis revealed an increase in the pseudo-capacitance from 0.09 µF to 4.13 µF and a reduction of charge transfer resistance that comes from the nanofiller contribution. MoS2 nanoflower introduces more active sites and expands the electroactive zone, thus improving the charge storage property of Cs. The Cs-MoS2 may offer a new route for the synthesis of eco-friendly, biodegradable, and electrical storage devices.

Improved electrochemical performance of multi-walled carbon nanotube reinforced gelatin biopolymer for transient energy storage applications.

Multi-walled carbon nanotube (MWCNT) incorporated biodegradable gelatin nanocomposites (Gel/MWCNT) have been prepared following a facile solution processing method. The Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electronic microscopy (FESEM), and water contact angle (WCA) measurements revealed improved structural properties and surface morphological features of the nanocomposite films due to the incorporation of MWCNT. A four-fold decrease in the DC resistivity was obtained due to the addition of MWCNTs. The specific capacitance of the nanocomposite increased from 0.12 F/g to 12.7 F/g at a current density of 0.3 µA/cm2 due to the incorporation of 0.05 wt.% MWCNT. EIS analysis and the corresponding Nyquist plots demonstrated the contributions of the different electrical components responsible for the improved electrochemical performance were evaluated using an equivalent AC circuit. The incorporation of MWCNTs was found to reduce the charge-transfer resistance from 127 Ω to 75 Ω and increase the double-layer capacitance from 4 nF to 9 nF. The Gel/MWCNT nanocomposite demonstrated improved cyclic stability with a retention of 95% of the initial capacitance even after 5000 charging/discharging cycles. The biodegradability test showed that the nanocomposite degraded completely after 30 hours of immersion in water. This fully biocompatible nature of the nanocomposites with high specific capacitance and low charge transfer resistance may offer a promising route to fabricate a nature-friendly electrode material for energy storage applications.

Effect of MWCNT nanofiller on the dielectric performance of bio-inspired gelatin based nanocomposites.

In this work, multi wall carbon nanotube (MWCNT) reinforced bio-derived gelatin-based polymer nanocomposites were synthesized following an easy and affordable solution-casting method. The effects of different concentrations of MWCNTs on the structural, surface morphological, and dielectric properties of the nanocomposites were studied. A four-fold increase in the dielectric constant is observed due to the incorporation of just 0.02 wt% of MWCNT nanofiller into the polymer matrix. The modified Cole-Cole model was used to analyze the effect of nanofiller concentrations on the different dielectric parameters of the nanocomposite. The incorporation of MWCNTs was found to increase the dielectric strength and reduce the relaxation time of the nanocomposite. The AC conductivity of the nanocomposites was found to be improved due to the incorporation of the MWCNT nanofiller. A quantitative study based on the simulation of the complex impedance spectra demonstrates that the addition of MWCNTs into the nanocomposite decreases the grain barrier resistance from 5935 kΩ to 261 kΩ and increases the capacitive component from 0 to 23.25 µF. The improved dielectric performance of the nanocomposites can be attributed to the space charge polarization effect and is illustrated with a charge transport mechanism model. This biopolymer-based nanocomposite material with a large dielectric constant together with a small loss tangent may offer a potential route for the fabrication of fully biocompatible electrostatic capacitors and energy storage devices.

Bio-inspired gelatin/single-walled carbon nanotube nanocomposite for transient electrochemical energy storage: An approach towards eco-friendly and sustainable energy system.

Wide-scale production of non-biodegradable e-waste from electrical appliances are causing great harm to the environment. The use of bio-polymer based nanomaterials may offer a promising approach for the fabrication of eco-friendly sustainable devices. In this work, gelatin/single walled carbon nanotube (Gel/SWCNT) nanocomposites were prepared by a simple and economic aqueous casting method. The effect of SWCNT on the structural, surface-morphological, electrical, and electrochemical properties of the nanocomposite was studied. Fourier transform infrared spectroscopy (FTIR) and field emission scanning electron microscope (FESEM) showed an improved degree of interaction between the SWCNTs and Gel matrix. The surface wettability of the nanocomposites was found to be changed from hydrophilic to hydrophobic in nature due to the incorporation of SWCNTs into the Gel matrix. The incorporation of SWCNTs was also found to reduce the DC resistivity of the nanocomposite by 4 orders of magnitude. SWCNTs also increase the specific capacitance of the nanocomposite from 124 mF/g to 467 mF/g at a current density of 0.3 mA/g. The electrochemical impedance spectroscopy analysis revealed an increase of the pseudo-capacitance increased from 9.4 µF to 31 µF due to the incorporation of SWCNT. The Gel/SWCNT nanocomposite showed cyclic stability with capacitive retention of about 98% of its initial capacitance after completing 2000 charging/discharging cycles at a current density of 100 mA/g. The nanocomposite completely dissolves in water within 12 h, demonstrates it as a promising candidate for transient energy storage applications. The Gel/SWCNT nanocomposite may offer a new route for the synthesis of eco-friendly, biodegradable, and transient devices.