Faculty Publications
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Item Single step synthesis of rGO, copper oxide and polyaniline nanocomposites for high energy supercapacitors(Elsevier Ltd, 2018) Viswanathan, A.; Nityananda Shetty, A.N.Reduced graphene oxide, copper oxide and polyaniline (GCP) nanocomposites possessing energy densities close to many of Li-ion batteries are synthesized by facile in-situ single step chemical method by varying the weight percentage of each of the constituent materials. Of all the composites synthesized, the one with weight percentage of G12%: Cu2O/CuO40%: P48% (G12CP) exhibits the maximum specific capacitance of 684.93 F g?1, specific capacity of 821.91 C g?1, energy density of 136.98 W h kg?1, and power density of 1315.76 W kg?1 at the current density of 0.25 A g?1. The composite shows the retention of 84% of its initial capacitance up to 5000 cycles at a scan rate of 700 mV s?1. The electrochemical performance of G12CP is superior to the performances of other ternary composites and those of binary composites synthesized with respective weight ratios as that of G12CP composite. The potential of G12CP to act as a secondary power backup device is successfully demonstrated and the performance obtained is comparable with some of the previously reported similar works, and even superior to some others. © 2018 Elsevier LtdItem High energy reduced graphene oxide/vanadium Pentoxide/polyaniline hybrid supercapacitor for power backup and switched capacitor converters(Academic Press Inc. apjcs@harcourt.com, 2019) Viswanathan, A.; Prakashaiah, B.G.; Subburaj, V.; Nityananda Shetty, A.N.The robust reduced graphene oxide (rGO)/vanadium pentoxide (V 2 O 5) /polyaniline (PANI) nanocomposite with a weight percentage of rGO – 5.88%: V 2 O 5 – 11.76%: PANI – 82.36%, was synthesized by facile insitu single step chemical method and fabricated into a supercapacitor device. The supercapacitor exhibited high energy density of 54.62 W h kg ?1 and an exceptionally high sustainability of its performance up to 13,000 rechargeable cycles at high charge/discharge rate. The high energy density was further confirmed when the supercapacitor containing the afore mentioned composite, acted as an excellent secondary power source to store and deliver energy for substantially long time when charged at an exceptionally high current using a commercial 9 V battery. Further, its energy storage and delivery capabilities were established by using it in a real time switched capacitor converter circuit and the obtained performance for potential step up and step-down purposes were gratifying. The obtained electrochemical parameters included a maximum specific capacitance of 273F g ?1 specific capacity of 327.6C g ?1 , energy density of 54.62 W h kg ?1 and a power density of 1636.5 W kg ?1 at a current density of 1 A g ?1 . © 2019 Elsevier Inc.Item Real time magnetic supercapacitor with antiferromagnetic nickel hydroxide based nanocomposite(Elsevier Ltd, 2019) Viswanathan, A.; Nityananda Shetty, A.N.An antiferromagnetic, semiconducting nickel hydroxide (Ni(OH) 2 ), with a good theoretical capacitance is composited with reduced graphene oxide and polyaniline to synthesize the electrode material for energy storage in supercapacitors. The composite overcomes the limitation of low conductivity of nickel hydroxide. The conductivity and antiferromagnetic nature of nickel hydroxide are altered by applying magnetic field, which in turn enhances its energy storing capacity. A ternary composite with the weight percentages of 4%: 48%: 48% of reduced graphene oxide/nickel hydroxide/polyaniline (GN48P), respectively, exhibits a magnetic susceptibility of 850. The application of a magnetic field of 625 ?T results in an enhancement of performance of the composite, exhibiting a specific capacitance of 19.14 F g ?1 , specific capacity of 22.97 C g ?1 , energy density of 0.6649 W h kg ?1 , a power density of 17.57 W kg ?1 at a current density of 0.25 A g ?1 and retention of 85.19% of its original capacitance up to 5000 cycles. This premier study on the effect of magnetic field, on the electrochemical performance of the supercapacitor in a typical two electrode system showed 69.4% increase in its specific capacitance. © 2019 Elsevier LtdItem High rate capable and high energy supercapacitor performance of reduced graphene oxide/Al(OH)3/polyaniline nanocomposite(Academic Press Inc., 2020) Viswanathan, A.; Gururaj Acharya, M.; Nityananda Shetty, A.N.The high rate capable, high energy (higher than the lead acid batteries & Nickel-cadmium batteries and comparable with Li-ion batteries) and long lasting supercapacitive performance was achieved from a ternary nanocomposite of rGO/Al(OH)3/PANI (5.88%:11.77%:82.85%) (GAlP82). The GAlP82 exhibited high cyclic stability till 47,500 cycles at 400 mV s?1, with increasing trend of specific capacitance (Cs) with increase in No. of energy storage/delivery cycles. After 41,500 cycles the GAlP82 exhibited a Cs of 490.19 F g?1, an energy density (E) of 98.03 W h kg?1 and a power density (P) of 2.2829 kW kg?1 at 1 A g?1. The GAlP82 exhibited a good rate capability by retaining 73% of Cs up to 10 A g?1 before cyclic stability study and 33% of Cs up to 23 A g?1 after 41,500 cycles; and all these impressive performances are achieved from the symmetric supercapacitor cell of GAlP82. © 2020 Elsevier Inc.Item 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 Reduced graphene oxide/polyaniline/vanadium pentoxide/stannic oxide quaternary nanocomposite, its high energy supercapacitance and green electrolyte(Springer, 2024) Viswanathan, A.; Nityananda Shetty, A.N.Challenge of achieving high energy density (E) comparable with Li-ion batteries in supercapacitors, with low potential window offering aqueous electrolytes (1.2 V) has been overcome by using the electrode material composed of rGO 3.70%:PANI 51.86%:V2O5 33.33%:SnO2 11.11% (GPVS). The GPVS exhibited different extents of energy storage in the presence of 1 M sulphuric acid (H2SO4) and acidified supernatant liquid (ASL), a green electrolyte. Here, the ASL is the by-product, which is obtained as supernatant liquid after the synthesis of GPVS composites in an in situ synthetic method, and acidified using conc. H2SO4. The energy storage obtained in the presence of ASL is 38% higher than the energy storage obtained in the presence of H2SO4. The GPVS exhibited a remarkable feature of amelioration of energy storage with increase in CV cycles in the presence of H2SO4. The GPVS exhibited an extraordinary cyclic stability up to 41,300 cycles. The energy storage parameters achieved in the presence of H2SO4 after 33,800 cycles are, a specific capacitance (Cs) of 694.44 F g?1, an E of 138.88 W h kg?1 (comparable with E of Li-ion batteries) and a power density (P) of 2.1020 kW kg?1 at 1 A g?1. The energy storage parameters achieved in the presence of ASL are, a Cs of 212.31 F g?1, an E of 42.46 W h kg?1 (comparable with E of Ni–Cd batteries) and a P of 3.1583 kW kg?1 at 2 A g?1. It is satisfying that all these high energy characters are achieved with the real two electrodes–supercapacitor cell step up. The green supercapacitors are made by using the by-product, which is obtained as supernatant liquid after the synthesis of GPVS as its electrolytes. © Indian Academy of Sciences 2024.Item Energy density comparable with Li-ion batteries from aqueous supercapatteries of PANI/V2O5/SnO2 nanocomposite and its green electrolytes(Elsevier B.V., 2025) Viswanathan, A.; Ramesh, T.P.; Naik, M.; Nityananda Shetty, A.N.The PANI53.85 %: V2O534.62 %: SnO211.53 % (PVS) ternary nanocomposite synthesized by insitu synthesis as supercapattery electrode material has exhibited energy density (E) equivalent to that of Li-ion batteries as the PVS furnishes an impressive E of 114.13 W h kg–1 with a high power density (P) of 2.400 kW kg–1 at 2 A g–1 in real 2 EL-supercapattery cell set up with low potential window (1.2 V) provided by 1 M H2SO4. The energy storage performance resulted by PVS is, a specific capacity (Q) of 684.8 C g–1, at 2 A g–1. The PVS is robust to withstand its energy storage characters up to 13600 cycles at 0.4 V s–1. The Li-ion supercapattery device of PVS made with a green electrolyte exhibited a Q of 672.0 C g–1, E of 112.0 W h kg–1 and P of 1.200 kW kg–1 at 1 A g–1. © 2025 The Authors