Faculty Publications
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Item The high energy supercapacitor from rGO/Ni(OH)2/PANI nanocomposite with methane sulfonic acid as dopant(Academic Press Inc. apjcs@harcourt.com, 2019) Viswanathan, A.; Nityananda Shetty, A.N.The low energy densities of supercapacitors limit their utilization as energy storage and energy conversion devices. To overcome this limitation, here we present a ternary nanocomposite of reduced graphene oxide (rGO)/nickel hydroxide (Ni(OH)2/polyaniline (PANI), with methane sulfonic acid as dopant, having weight percentages of 14%:14%:72% (G14NP), respectively, as an electrode material for supercapacitor. With 1 M sulfuric acid (H2SO4) as the electrolyte, the supercapacitor yields a high energy density of 120.48 W h kg?1, comparable with those of Li-ion batteries. The G14NP also exhibits good electrochemical performance with a specific capacitance of 602.40 F g?1 and a power density of 2584.83 W kg?1, at a current density of 1 A g?1. The G14NP also exhibits a promising stability of its electrochemical performances even after 16,500 cycles at a potential scan of 400 mV s?1. Remarkably, the composite performs exceptionally well at a potential window available in an aqueous electrolyte. The sustainability to high current loading while charging and its power backup application is satisfactorily demonstrated, by charging with a commercial 9 V battery. © 2019 Elsevier Inc.Item Enhancement of supercapacitance of reduced graphene oxide, copper oxide and polyaniline using the mixture of methane sulphonic acid and sulphuric acid as electrolyte(Elsevier Ltd, 2021) Viswanathan, A.; Nityananda Shetty, A.N.The mixture of mineral acid and organic acid as aqueous electrolyte for the rGO12%: Cu2O/CuO40%: PANI48% (G12CP) nanocomposite, exhibited superior energy storage performance. The acid mixture electrolyte used is 0.4 M H2SO4 + 0.4 M CH3SO3H (1:1) (SA + MSA) and it exhibited enhanced diffusion and kinetic features in comparison with the bare 0.4 M H2SO4 (SA) and 0.4 M CH3SO3H (MSA). SA + MSA provided 16.8% higher energy storage than the SA and the performance obtained after 5000 charge/discharge cycles is 276.98% higher than the performance obtained before the cyclic stability test using the same acid mixture electrolyte. The G12CP provided a specific capacitance (Cs) of 490.19 F g?1, an energy density (E) of 98.0392 W h kg--1 and a power density (P) of 1.500l kW kg?1 at 1 A g?1 in the presence of SA + MSA. The obtained E is comparable with E of Li-ion batteries, Ni-metal hydride batteries, Na-S batteries, and Na-metal chloride batteries. © 2020 Elsevier LtdItem Superior supercapacitance exhibited by acid insoluble Ni(OH)2 in the form of its nanocomposite with rGO(Elsevier Ltd, 2022) Viswanathan, A.; Acharya, M.G.; Prakashaiaha, B.G.; Nityananda Shetty, A.N.The solubility of Ni(OH)2 in acids was been the major impediment that has been preventing the usage of acid electrolytes like 1 M H2SO4 in supercapacitors and batteries that contain Ni(OH)2 as electrode material. This impediment is successfully removed and impressive energy storage characters were achieved from an electrode made up of Ni(OH)2 in the presence of acid electrolyte of 1 M H2SO4. This acid insoluble form of Ni(OH)2 was achieved by synthesizing it in situ in the presence of graphene oxide by chemical reduction method to produce the stable nanocomposite of reduced graphene oxide (rGO) and Ni(OH)2. The insolubility of Ni(OH)2 in 1 M H2SO4 was carefully studied for nearly six months and proved to be a factual observation. Remarkably, the rGO/Ni(OH)2 composite exhibited the better energy storage performance in the presence of 1 M H2SO4 in relation with conventional methods that involve basic electrolytes like NaOH and KOH for Ni(OH)2. The supercapacitor containing rGO/Ni(OH)2 composite and 1 M H2SO4, was stable in storing and delivering the energy without deterioration up to 31,500 cycles, with an uniqueness of increase in energy storage with increase in cycles of energy storage and delivery. Remarkably, two type of faradaic processes are observed to be contributing to the total energy storage of Ni(OH)2, of which one is unprecedented. The superior specific energy (E) and specific capacitance (Cs) achieved are 130.7175 W h kg−1 (comparable with Li-ion batteries of 3 V) and 653.5947 F g−1 at 1 A g−1. This superior Cs is higher than the theoretical Cs expected from this composite for this specific composition (rGO33.33 % and Ni(OH)2 66.66 %) (1571 F g−1) and higher than the theoretical Cs of Ni(OH)2 (2082 F g−1). It is expected that this study would be an inevitable attraction and take the applicability of Ni(OH)2 to higher level and make it one of the meritorious materials for future energy storage. © 2022 Elsevier LtdItem Supporting electrolyte enhanced supercapacitance of acetic acid doped reduced graphene oxide/nickel hydroxide/polyaniline nanocomposites(Elsevier Ltd, 2023) Viswanathan, A.; Nityananda Shetty, A.N.The rapidly enhanced electrolytic intercalation bringing about 101 % higher energy storage in rGO, Ni(OH)2 and PANI (GNP) nanocomposite in comparison with 1 M H2SO4 is achieved using the 0.4 M CH3SO3H (MSA) as supporting electrolyte for 0.4 M H2SO4 (SA). Ensuing the established fact of acid insoluble Ni(OH)2 in our earlier study, the further work on Ni(OH)2 containing composites in the presence of acid electroytes has proven its stability in MSA as well. The GNP exhibited increase in specific capacitance (Cs) on increasing the cycles of energy storage and delivery in different acid electrolytes but the enhancement in the presence of MSA is higher. The superior results were achieved from the supercapacitor device containing GN51P (rGO 3.70 %: Ni(OH)2 51.86 %: PANI44.44 %) and SA + MSA, which are, Cs of 381.67 F g−1, specific capacity (Q) of 458.01 C g−1, E of 76.33 W h kg−1 and a specific power of 3.3109 kW kg−1 at 1 A g−1. The GN51P exhibited increasing Cs even after 10,000 cycles at 400 mV s−1. The real time applications of the GNP composites are also experimented satisfactorily. © 2023 Elsevier LtdItem Durable and high energy yielding PANI/Ni(OH)2 nanocomposites and its supporting electrolyte improved supercapacitance(Elsevier Ltd, 2024) Viswanathan, A.; Nityananda Shetty, A.N.The driving force behind supercapacitor research is to enhance the energy density (E) to the level of Li-ion batteries, and achieving high power density (P). This task is accomplished by using nanocomposites of polyaniline (PANI) and Ni(OH)2 (PN) as the electrode material for supercapacitors. These nanocomposites were synthesized using acetic acid (PN - AA) (PANI 75% and Ni(OH)2 25%) and methane sulphonic acid (PN - MSA) (PANI 83.33% and Ni(OH)2 16.67%) as dopants for PANI through an in-situ single-step method. The PN – MSA exhibited higher energy storage characters than PN – AA with 1 M H2SO4 (SA) as electrolyte. PN - MSA exhibited high-energy characteristics, including a specific capacitance (Cs) of 735.29 F g‒1, an energy density (E) of 147.05 W h kg‒1 (comparable to Li-ion batteries), and a power density (P) of 2.3466 kW kg‒1 at 1 A g‒1. In addition, it also exhibited an exceptional cyclic stability up to 58,800 cycles at 0.4 V s‒1. The energy characters of PN-AA are also substantially high and are a Cs of 641.02 F g‒1, an E of 128.20 W h kg‒1 (in the same order of Li-ion batteries), a P of 2.0385 kW kg‒1 at 1 A g‒1 and a cyclic stability up to 18,400 cycles was also obtained at 0.4 V s‒1. Both PN - AA and PN - MSA demonstrated an impressive feature of an increase in energy storage with an increase in the number of charge/discharge cycles. PN - MSA exhibited an improvement in energy storage characteristics of up to 44% when a mixture of sulphuric acid and methane sulphonic acid with concentrations of 1 M and 0.33 M, respectively, was used as an electrolyte. © 2024 Elsevier LtdItem Nanoporous PANI/ZnO/VO2 ternary nanocomposite and its electrolyte for green supercapacitance(Elsevier Ltd, 2024) Viswanathan, A.; Nityananda Shetty, A.N.The green process of energy storage by utilizing the by-product obtained after the synthesis of PANI54.69 %: ZnO7.81 %: VO237.50 % (PZnV) nanocomposite by insitu single step method, as its electrolyte is demonstrated herein. This green approach yields 23 % improvement in the energy storage compared to that in the presence of 1 M H2SO4. The enhanced energy storage obtained for PZnV nanocomposite in the presence of acidified by-product are a specific capacitance (Cs) of 177.3 F g−1, a specific capacity (Q) of 212.7 C g−1, an energy density (E) of 35.46 W h kg−1 (comparable with E of lead acid batteries), and a power density (P) of 1.632 kW kg−1 at 1 A g−1. The PZnV exhibited an unique feature of increase in energy storage with increase in No. of CV cycles in the presence of 1 M H2SO4, and the maximum energy storage was achieved after 12,312 cycles with a Cs of 440.5 F g−1, a Q of 528.6 C g−1, an E of 88.10 W h kg−1 (comparable with E of Li-ion batteries), and a P of 2.154 kW kg−1. A good cyclic stability up to 16,812 cycles was achieved at 0.4 V s−1. © 2024 Elsevier B.V.Item High energy supercapattery of polyaniline/cupric oxide/stannic oxide nanocomposite(Elsevier Ltd, 2024) Viswanathan, A.; Nityananda Shetty, A.N.The effects of different aqueous acid electrolytes in imparting different features of energy storage to the nanocomposite of PANI50 %: CuO41.7 %: SnO28.3 % (PCS) are studied with three different electrolytes 1 M H2SO4 (SA), 1 M H2SO4 + 1 M CH3SO3H (1:1) (SA + MSA) and acidified by-product (ABP). In the presence of SA, SA + MSA and ABP, the PCS produces, high energy density (E); high E & cyclic stability; and high E & rate capability, respectively. The maximum energy characters are achieved in the presence of SA + MSA. They are specific capacity (Q) of 301.6 C g−1, E of 50.26 W h kg−1 and power density (P) of 1.200 kW kg−1 at 1 A g−1. In the presence of SA + MSA the PCS nanocomposite exhibits 55.56 % retention of its initial Q up to 12500 cycles at 0.4 V s−1. This achieved high E is similar with E of Ni–Cd batteries. The use of by-product as electrolyte for supercapattery makes the process a green process. © 2024 Elsevier LtdItem A green approach to energy storage properties of polyaniline(Springer, 2024) Viswanathan, A.; Nityananda Shetty, A.N.The green energy storage of polyaniline, without major wastages excreted into the environment is effectively demonstrated by using the polyaniline as supercapacitor electrode and the by-product obtained during the synthesis of polyaniline as its electrolyte. This green approach to the energy storage properties of sulphuric acid doped polyaniline (H-PANI) exhibited a substantial improvement in its energy storage, compared to the conventional approach of using an ionically conducting liquid as electrolyte like 1 M H2SO4 (SA), separately. The amelioration of 40.44% was achieved when the by-product obtained as supernatant liquid (SL) was used as electrolyte compared to SA. The H-PANI provided a specific capacity (Q) of 146.4 C g?1, a specific energy (E) of 24.40 W h kg?1 and a specific power (P) of 1.200 kW kg?1 at 1 A g?1 in the presence of SA. The Q of 205.6 C g?1, E of 34.26 W h kg?1 (similar range of E of Pb-acid batteries), P of 1.200 kW kg?1 were achieved in the presence of SL at 1 A g?1 and a high rate capability of 29.18% retention of initial Q up to 25 A g?1 was also achieved. This approach is useful to harvest high energy characters from PANI. © Indian Academy of Sciences 2024.