High-energy green supercapacitor driven by ionic liquid electrolytes as an ultra-high stable next-generation energy storage device

Thangavel, Ranjith,Kannan, Aravindaraj G.,Ponraj, Rubha,Thangavel, Vigneysh,Kim, Dong-Won,Lee, Yun-Sung Elsevier 2018 Journal of Power Sources Vol.383 No.-

<P><B>Abstract</B></P> <P>Development of supercapacitors with high energy density and long cycle life using sustainable materials for next-generation applications is of paramount importance. The ongoing challenge is to elevate the energy density of supercapacitors on par with batteries, while upholding the power and cyclability. In addition, attaining such superior performance with green and sustainable bio-mass derived compounds is very crucial to address the rising environmental concerns. Herein, we demonstrate the use of watermelon rind, a bio-waste from watermelons, towards high energy, and ultra-stable high temperature green supercapacitors with a high-voltage ionic liquid electrolyte. Supercapacitors assembled with ultra-high surface area, hierarchically porous carbon exhibits a remarkable performance both at room temperature and at high temperature (60 °C) with maximum energy densities of ∼174 Wh kg<SUP>−1</SUP> (25 °C), and 177 Wh kg<SUP>−1</SUP> (60 °C) – based on active mass of both electrodes. Furthermore, an ultra-high specific power of ∼20 kW kg<SUP>−1</SUP> along with an ultra-stable cycling performance with 90% retention over 150,000 cycles has been achieved even at 60 °C, outperforming supercapacitors assembled with other carbon based materials. These results demonstrate the potential to develop high-performing, green energy storage devices using eco-friendly materials for next generation electric vehicles and other advanced energy storage systems.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hierarchal porous carbon is obtained from waste watermelon rind. </LI> <LI> The biomass carbon exhibits high surface area along with micro and mesopores. </LI> <LI> A high voltage supercapacitor is constructed with ionic liquid electrolyte. </LI> <LI> The supercapacitor delivers high energy (174 Wh kg<SUP>−1</SUP>) and high power (20 kW kg<SUP>−1</SUP>). </LI> <LI> The supercapacitor exhibits remarkable stability (150,000 cycles) at 60 °C. </LI> </UL> </P>

Nitrogen- and sulfur-enriched porous carbon from waste watermelon seeds for high-energy, high-temperature green ultracapacitors

Thangavel, Ranjith,Kannan, Aravindaraj G.,Ponraj, Rubha,Thangavel, Vigneysh,Kim, Dong-Won,Lee, Yun-Sung The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.36

<P>Electrochemical ultracapacitors exhibiting high energy output and an ultra-long cycle life, utilizing green and sustainable materials, are of paramount importance for next-generation applications. Developing an ultracapacitor that has high output energy under high power conditions in a high-voltage non-aqueous electrolyte and maintaining a long cycle life is an ongoing challenge. Herein, we utilize watermelon seeds, a bio-waste from watermelons, for use in high-voltage, high-energy, and high-power ultracapacitors in a sodium ion-based non-aqueous electrolyte. The as-synthesized hierarchically porous, high surface area carbon is surface-engineered with a large quantity of nitrogen and sulfur heteroatoms to give a high specific capacitance of ∼252 F g<SUP>−1</SUP> at 0.5 A g<SUP>−1</SUP> and 90 F g<SUP>−1</SUP> at 30 A g<SUP>−1</SUP>. An ultra-high stability of ∼90% even after 150 000 cycles (10 A g<SUP>−1</SUP>) with 100% coulombic efficiency is achieved at room temperature (25 °C), equivalent to an ultra-low energy loss of ∼0.0667% per 1000 cycles. Furthermore, the porous carbon demonstrates remarkable stability even at high temperature (55 °C) for 100 000 cycles (10 A g<SUP>−1</SUP>), ensuring the safety of the device and enabling it to outperform graphene-based materials. A maximum energy of ∼79 W h kg<SUP>−1</SUP> and a maximum power of 22.5 kW kg<SUP>−1</SUP> with an energy retention of ∼28.2 W h kg<SUP>−1</SUP> was attained. The results provide new insights that will be of use in the development of high-performance, green ultracapacitors for advanced energy storage systems.</P>

Synthesis and characterization of kaempferol-based ruthenium (II) complex: A facile approach for superior anticancer application

Thangavel, Prakash,Viswanath, Buddolla,Kim, Sanghyo Elsevier 2018 Materials Science and Engineering C Vol.89 No.-

<P><B>Abstract</B></P> <P>In this study, we synthesized a novel metal flavonoid complex and investigated its effects on the non-small cell lung cancer cell lines, A549 and toxicity on the human dermal fibroblast cell lines, HDFa. <SUP>1</SUP>H, <SUP>13</SUP>C NMR, single crystal X-ray diffraction and elemental micro analysis (C,H,N,S/O) were used to characterize the synthesized kaempferol-based Ru (II) complex. Cell toxicity was studied using MTT assay and electric cell substrate impedance sensing (ECIS). It was evident from the MTT results that no significant cytotoxicity in HDFa cells occurs with the synthesized complex, but in case of A549 cells, significant cytotoxicity was observed even at low concentrations (10-20 μm). In addition, the effect of the newly synthesized complex on the A549 cell line was studied by investigating the cellular damage via atomic force microscopy and DNA fragmentation assay. The obtained results revealed that the synthesized complex was able to inhibit the cancer cells and have shown moderate anticancer activity against A549 cancer cell lines. In addition, it was evident that the complex was more active than kaempferol and well tolerated by normal cell lines.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Successfully synthesized a kaempferol-based ruthenium (II) complex </LI> <LI> <SUP>1</SUP>H, <SUP>13</SUP>C NMR, single crystal XRD and elemental micro analysis were used to characterize the complex. </LI> <LI> The synthesized complex strongly inhibited the growth of non-small cell lung cancer cell lines (A549) </LI> <LI> The synthesized complex is less active toward the human dermal fibroblast cell lines (HDFa). </LI> </UL> </P>

All-Organic Sodium Hybrid Capacitor: A New, High-Energy, High-Power Energy Storage System Bridging Batteries and Capacitors

Thangavel, Ranjith,Kaliyappan, Karthikeyan,Kim, Dae-Ung,Sun, Xueliang,Lee, Yun-Sung American Chemical Society 2017 Chemistry of materials Vol.29 No.17

<P>The development of hybrid capacitors (HCs) has become essential for meeting the rising demand for devices that simultaneously deliver high energy with high power. Although the challenge to develop high-performance HCs remains great, it is also simultaneously essential to develop an eco-friendly and cleaner energy storage system for sustainable future use. To date, hybrid capacitors utilize heavily toxic inorganic insertion electrodes and hazardous coke-derived porous carbon adsorption electrodes to host ions. Herein, we present a conceptually novel all-organic sodium hybrid capacitor (OHC), rationally designed by replacing the conventional electrodes with clean, green, and metal free organic molecules, to host ions. A high energy density of similar to 95 Wh kg(-1) and an ultrahigh power density of 7 kW kg(-1) (based on active mass in both electrodes) are achieved with a low energy loss of similar to 0.22% per 100 cycles (similar to 89% retention after 5000 cycles), outperforming conventional HCs. The outstanding energy-power behavior of OHC bridges the performance gap between batteries and capacitors. This research holds great promise for the development of next-generation eco-friendly, clean, green, and safer high-energy, high-power devices.</P>

Investigation of the Mechanical Behaviour of Nylon 6 – Silicon Carbide (SiC) – Mica Polymer Matrix Composites

Thangavel Anand 한국고분자학회 2023 폴리머 Vol.47 No.6

The interest in nylon composites is growing as a result of their high strength, high toughness, and low coef-ficient of friction. For a while, researchers have used a variety of fillers to improve the mechanical and tribological char-acteristics of nylons. Despite extensive research, the current study is being carried out to explore the various mechanical behaviors of a nylon 6 hybrid polymer matrix composite due to its strength, stiffness, and lightness. In this work, silicon carbide and mica were used as fillers, and nylon 6 was used as the matrix. Mica was taken at 2.5, 5, and 7.5 wt%, and silicon carbide was taken at 2 wt%. After the ingredients were combined in a twin screw extruder, the samples were made using an injection moulding procedure. According to ASTM D256, D790, and D638, the specimens for the impact, flex-ural, and tensile tests were prepared. Tests and analyses were done on the impact, flexural, and tensile strengths. In tensile and flexural testing, the strength of the nylon 6 composite with 2 wt% silicon and 7.5 wt% mica was higher than that of pure nylon 6 by 19.48% and 17.65%, respectively. The reduction in the impact strength was 24.7%. The composites' surface morphology was investigated using a scanning electron microscope.

Pushing the Energy Output and Cyclability of Sodium Hybrid Capacitors at High Power to New Limits

Thangavel, Ranjith,Moorthy, Brindha,Kim, Do Kyung,Lee, Yun-Sung Wiley Blackwell (John Wiley Sons) 2017 Advanced energy materials Vol.7 No.14

<P>Hybrid capacitors, especially sodium hybrid capacitors (NHCs), have continued to gain importance and are extensively studied based on their excellent potential to serve as advanced devices for fulfilling high energy and high power requirements at a low cost. To achieve remarkable performance in hybrid capacitors, the two electrodes employed must be superior with enhanced charge storage capability and fast kinetics. In this study, a new sodium hybrid capacitor system with a sodium super ionic conductor NaTi2(PO4)(3) grown on graphene nanosheets as an intercalation electrode and 2D graphene nanosheets as an adsorption electrode is reported for the first time. This new system delivers a high energy density of approximate to 80 W h kg(-1) and a high specific power of 8 kW kg(-1). An ultralow performance fading of approximate to 0.13% per 1000 cycles (90%-75 000 cycles) outperforms previously reported sodium ion capacitors. The enhanced charge transfer kinetics and reduced interfacial resistance at high current rates deliver a high specific energy without compromising the high specific power along with high durability, and thereby bridge batteries and capacitors. This new research on kinetically enhanced NHCs can be a trendsetter for the development of advanced energy storage devices requiring high energy-high power.</P>

Antimicrobial Efficacy of Leuconostoc spp. Isolated from Indian Meat against Escherichia coli and Listeria monocytogenesin Spinach Leaves

Thangavel, Gokila,Subramaniyam, Thiruvengadam Korean Society for Food Science of Animal Resource 2019 한국축산식품학회지 Vol.39 No.4

Five Leuconostoc strains (CM17, CM19, PM30, PM32, and PM36) previously isolated from Indian meat showed promising antimicrobial activity against food pathogens in screening assay. This study evaluates the efficacy of these isolates against Escherichia coli Microbial Type Culture Collection and Gene Bank (MTCC) 443 and Listeria monocytogenes (MTCC 657) in spinach leaves. Challenge studies were conducted by inoculating E. coli and L. monocytogenes at 6 to 7 $Log_{10}CFU/g$ of the leaves respectively and treating them with cell free supernatant (CFS) of 48 h cultures of the isolates. The samples were stored at $4^{\circ}C$ and analyzed over a period of 5 d. The study was conducted in triplicates and statistical analysis was carried out using one-way Anova. The counts of the pathogens did not increase over the 5 d period in the control samples, without any treatment. Whereas in the case of CFS treatments, significant reduction (p<0.05) was observed in both E. coli and L. monocytogenes from 1 to 5 d with all the 5 strains as compared to the control. The counts of Listeria dropped by 0.5 to 1 log by 5 d, with PM 36 showing the highest reduction (1 log). In the case of E. coli, 1.1 to 1.5 log reduction was observed by 5 d, with again PM 36 showing the highest reduction (1.5). The overall results indicate that the isolates (specifically PM36) not only showed efficacy in in vitro studies but are also proved to be effective in food matrix making them potential clean label antimicrobial alternatives for food application.

Designing ZnS decorated reduced graphene-oxide nanohybrid via microwave route and their application in photocatalysis

Thangavel, S.,Krishnamoorthy, K.,Kim, S.J.,Venugopal, G. Elsevier Sequoia 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.683 No.-

In this study, we demonstrated the facile design of zinc-sulphide decorated reduced graphene-oxide (ZnS-rGO) nanohybrid via microwave method and examined their photocatalytic properties. The physico-chemical properties of the ZnS-rGO were analysed using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, high resolution scanning electron microscopy, energy dispersive X-ray spectroscopy and laser Raman analyses, respectively. The photocatalytic activity of the prepared ZnS-rGO nanohybrid was examined by the degradation of two model dyes Methylene blue (MB) and Rhodamine-B (RhB). The experimental results suggested that the designed ZnS-rGO nanohybrid possess superior photocatalytic activity with 1.47 and 2.92 fold higher reaction rates for MB and RhB degradation than that of the pure ZnS nanoparticles. A plausible mechanism for the enhanced properties of ZnS-rGO nanohybrid was discussed using photoluminescence spectra. Further, the role of reactive oxygen species on the photocatalytic properties of ZnS-rGO nanohybrid was investigated using appropriate electron and hole scavengers.

Recent developments in the nanostructured materials functionalized with ruthenium complexes for targeted drug delivery to tumors

Thangavel, Prakash,Viswanath, Buddolla,Kim, Sanghyo DOVE MEDICAL PRESS 2017 INTERNATIONAL JOURNAL OF NANOMEDICINE Vol.12 No.-

<P>In recent years, the field of metal-based drugs has been dominated by other existing precious metal drugs, and many researchers have focused their attention on the synthesis of various ruthenium (Ru) complexes due to their potential medical and pharmaceutical applications. The beneficial properties of Ru, which make it a highly promising therapeutic agent, include its variable oxidation states, low toxicity, high selectivity for diseased cells, ligand exchange properties, and the ability to mimic iron binding to biomolecules. In addition, Ru complexes have favorable adsorption properties, along with excellent photochemical and photophysical properties, which make them promising tools for photodynamic therapy. At present, nanostructured materials functionalized with Ru complexes have become an efficient way to administer Ru-based anticancer drugs for cancer treatment. In this review, the recent developments in the nanostructured materials functionalized with Ru complexes for targeted drug delivery to tumors are discussed. In addition, information on “traditional” (ie, non-nanostructured) Ru-based cancer therapies is included in a precise manner.</P>

Engineering the Pores of Biomass-Derived Carbon: Insights for Achieving Ultrahigh Stability at High Power in High-Energy Supercapacitors

Thangavel, R.,Kaliyappan, K.,Ramasamy, H. V.,Sun, X.,Lee, Y. S. WILEY-VCH 2017 CHEM SUS CHEM Vol.10 No.13