Faculty Publications

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Author: search.filters.author.Viswanathan, A.Subject: search.filters.subject.Specific capacitance

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    Electrochemical comparison of nickel and nickel hydroxide nanoparticles composited with reduced graphene oxide and polyaniline for their supercapacitor application
    (American Institute of Physics Inc. subs@aip.org, 2018) Viswanathan, A.; Nityananda Shetty, A.
    The reduced graphene oxide/polyaniline/Ni(OH)2 (GP-Ni(OH)2) and reduced graphene oxide/polyaniline/Ni (GP-Ni) nanocomposites were synthesized by facile in situ single step chemical method. The constituents were confirmed by powder-XRD, and the electrochemical characterizations were carried out using cyclic voltammetry(CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS). The electrochemical contribution of Ni(OH)2 and Ni to their supercapacitance along with reduced graphene oxide and polyaniline was compared. The GP-Ni nanocomposite exhibited a specific capacitance of 266.66 F g-1, energy density of 53.33 W h kg-1 and power density of 1385 W kg-1 at a current density of 0.25 A g-1 and the results were enhanced to 21% and more promising than that of nanocomposite GP-Ni(OH)2. © 2018 Author(s).
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    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 Ltd
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    Reduced graphene oxide/vanadium pentoxide nanocomposite as electrode material for highly rate capable and durable supercapacitors
    (Elsevier Ltd, 2020) Viswanathan, A.; Nityananda Shetty, A.N.
    The nanocomposite from reduced graphene oxide (rGO) and vanadium pentoxide (V2O5) was synthesized by the chemical method to obtain a nanocomposite of rGO 7.69% /V2O5 92.31% (GV). The role of faradaic V2O5 in storing high energy, in combination with rGO was studied and the energy storing parameters were determined from the liner discharge (from the slope of the discharge curve) approach and the non-linear discharge approach (from the integrated area of the discharge curve). The appropriateness of these methods is a matter of diverse views among the researchers when the specific capacitance (Cs) of the composite electrode material, comprising of both non-faradaic and faradic material, has to be determined. The energy storage parameters obtained from these two different approaches are found to be differing to a large extent. The energy storage parameters obtained from linear discharge approach are, a high specific capacitance (Cs) of 120.62 F g?1, a specific capacity (Q) of 144.74 C g?1, an energy density (E) of 24.12 W h kg?1 a power density (P) of 2.647 kW kg?1 and a columbic efficiency (?) of 79.22% at a current density of 2 A g?1. The nanocomposite retained 100% of its initial Cs up to 5000 cycles. Also retained 38% of its initial Cs, after 10,600 cycles at a potential scan of 400 mV s?1. © 2019
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    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.
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    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 Ltd
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    Quick responsive and durable supercapacitive performance of rGO/Zn(OH)2/PANI nanocomposites
    (Springer, 2021) Viswanathan, A.; Nityananda Shetty, A.; Bharath, S.P.; Mahendra, K.
    The quick responsive and durable supercapacitive performance was achieved from reduced graphene oxide/zinc hydroxide/polyaniline (rGO5.88%/Zn(OH)211.77%/PANI82.35%) (GZnP82) nanocomposite, synthesized by in-situ single step. The GZnP82 provided a specific capacitance (Cs) of 173.60 F g?1, a specific capacity (Q) of 208.32 C g?1, a specific energy of 34.7220 W h kg?1 and a specific power of 1516.8 W kg?1 at 0.25 A g?1. The GZnP82 exhibits only 28% decay of its initial Cs up to 12500 cycles at 2 A g?1. The GZnP82 is fast in response with the relaxation time (?) of 1.52 s. The capacitance of GZnP82 device obtained from impedance spectroscopy is 1.29 F. The comparison of electrochemical performance of GZnP82 measured from both chronopotentiometry and impedance spectroscopy, with similar reported energy storage materials, apprises that the achieved performances are of similar order; and better than, the reported materials. Most importantly, the addition of Zn(OH)2 has rendered the negative contribution to the GZnP82, as the binary combination of it, the rGO/PANI furnished higher performances than the GZnP82. © 2021, Indian Academy of Sciences.
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    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.