Browsing by Author "Viswanathan, A."

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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.
Amelioration of supercapacitance of mixed metal oxide dispersed reduced graphene oxide and polyaniline nanocomposites using Ch3SO3H as supporting electrolyte in H2SO4
(2019) Viswanathan, A.; Nityananda, Shetty, A.
Reduced graphene oxide/polyaniline/ Cu2O-SnO2 (5:2) nanocomposite was synthesised by facile in-situ one step chemical method. Its composition and structural morphology were characterized using powder-XRD, energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The capacitive performances were evaluated using cyclic voltammetry (CV), galvanostatic charge � discharge(GCD), and electrochemical impedance spectroscopy (EIS) with 0.4 M H2SO4 and a mixture of 0.4 M H2SO4 and 0.4 M CH3SO3H (1:1) as electrolytes. The amelioration of electrochemical parameters was observed in the mixture of electrolytes. The specific capacitance of 230.41 F g�1, energy density of 46.08 W h kg�1, and power density of 1530.39 W kg�1 were obtained. The enhancement of the electrochemical properties was found to be about 20 % with the mixture of 0.4 M H2SO4 and 0.4 M CH3SO3H (1:1) over bare 0.4 M H2SO4. � 2019 Elsevier Ltd. All rights reserved.
Amelioration of supercapacitance of mixed metal oxide dispersed reduced graphene oxide and polyaniline nanocomposites using Ch3SO3H as supporting electrolyte in H2SO4
(Elsevier Ltd, 2019) Viswanathan, A.; Nityananda Shetty, A.
Reduced graphene oxide/polyaniline/ Cu2O-SnO2 (5:2) nanocomposite was synthesised by facile in-situ one step chemical method. Its composition and structural morphology were characterized using powder-XRD, energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). The capacitive performances were evaluated using cyclic voltammetry (CV), galvanostatic charge â€“ discharge(GCD), and electrochemical impedance spectroscopy (EIS) with 0.4 M H2SO4 and a mixture of 0.4 M H2SO4 and 0.4 M CH3SO3H (1:1) as electrolytes. The amelioration of electrochemical parameters was observed in the mixture of electrolytes. The specific capacitance of 230.41 F gâ€“1, energy density of 46.08 W h kgâ€“1, and power density of 1530.39 W kgâ€“1 were obtained. The enhancement of the electrochemical properties was found to be about 20 % with the mixture of 0.4 M H2SO4 and 0.4 M CH3SO3H (1:1) over bare 0.4 M H2SO4. Â© 2019 Elsevier Ltd. All rights reserved.
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 Ltd
Effect of dopants on the energy storage performance of reduced graphene oxide/polyaniline nanocomposite
(Elsevier Ltd, 2019) Viswanathan, A.; Nityananda Shetty, A.N.
The nanocomposites comprising of reduced graphene oxide (rGO) and polyaniline (PANI) were synthesized by facile insitu single step chemical methods, with glacial acetic acid (AA) and methane sulphonic acid (MSA) as dopants for PANI. The rGO/PANI nanocomposites synthesized with the similar weight percentages of constituents exhibited better electrochemical performance in the presence of MSA than in the presence of AA, in the real two-electrode supercapacitor cell system. The nanocomposite of weight percentages of rGO-6.7%, and PANI-93.33% (GP93MSA), with MSA as dopant exhibited a remarkable feature of increase in energy storage when the number of cycles was increased. It exhibited a maximum enhancement of 237.44% in its energy storage performance, after 13600 cycles as compared to the performance before the onset of cyclic test. The high performances obtained with GP93MSA include high specific capacitance of 512.82 F g?1, specific capacity of 615.38 C g?1, energy density of 102.56 W h kg?1 and a power density of 1.8954 kW kg?1 at 1 A g?1. The energy density of the supercapacitor with GP93MSA as the electrode material, is of the same order as that of Li-ion batteries. Also, GP93MSA showcased good cyclic stability up to 23000 cycles. © 2019 Elsevier Ltd
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. Â© 2018 Author(s).
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
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
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.
High energy supercapacitance of magnetic PANI/Ni2O3 nanocomposite and its magnetic structural repair
(Elsevier Ltd, 2024) Viswanathan, A.; Nityananda Shetty, A.N.
A magnetically auto healable and robust supercapacitor from a nanocomposite of PANI68.1 %: Ni2O331.9 % (PNi) synthesized in an in situ single step method, is achieved. PNi provided an exceptional character of healing the structural damage of PANI by the magneticity of Ni2O3 nanoparticles and showed a feature of increase in energy storage with increase in No. of charge/discharge cycles. The PNi exhibited a cyclic stability up to 16,800 cycles without significant reduction in initial Cs. The energy storage parameters achieved after 10,000 cycles are specific capacitance (Cs) of 347.6 F g−1, specific energy (E) of 69.52 W h kg−1, which is in the regime of E of Ni-metal hydride batteries of 0.9–1.3 V potential range, and specific power (P) of 8.571 kW kg−1 at 3 A g−1. Therefore, the PNi would be of a potential electrode material for the fabrication of long withstanding, robust and self - magnetically healable supercapacitor that delivers high energy. © 2024 Elsevier Ltd
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 Ltd
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.
Influence of different dopants and redox forms of PANI in its crystal structure, morphology, electrochemical energy storage to variable extent, unique properties and kinetics
(Springer, 2022) Viswanathan, A.; Nityananda Shetty, A.N.
The influences of base and salt forms, dopants used for protonation and different oxidation states of polyaniline (PANI) on its crystal structure, morphology, electrochemical stability, electrical conductivity and different potential-dependent energy storage by electrochemical processes were investigated by synthesizing PANI with two different acid dopants and in two different redox forms. The results reveal that, the methane sulphonic acid (MSA) causes more storage of energy in PANI. The reduced form of PANI furnishes high surface area and stores more energy than the respective oxidized form. The MSA-doped PANI exhibits an inimitable property of increase of specific capacitance (Cs) with increase in number of charge/discharge cycles in both oxidized and reduced forms. The structural changes of PANI after 25600 cycles were determined by IR spectroscopy, which confirmed that the irreversible formation of pernigraniline causes property degradation of PANI. The maximum energy storage parameters obtained from oxidized form of PANI doped with MSA (PANIMSA-Ox) are a Cs of 458 F g−1, a specific energy (Es) of 91 W h kg−1 and a specific power (Ps) of 2.0983 kW kg−1 at 1 A g−1. In addition, the PANIMSA-Ox exhibits an exceptional cyclic stability up to 25600 at 0.4 V s−1. The theoretical capacitance of PANI (2000 F g−1) is nearly reached with PANIMSA-Ox as it provided the Cs of an electrode of 1834.84 F g−1 at 1 A g−1. Most significantly, the PANIMSA-Ox presents the maximum of four faradaic couples and exceptional energy storage without using any redox supporting electrolytes. Graphical abstract: [Figure not available: see fulltext.] © 2022, Indian Academy of Sciences.
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.
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.
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
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.
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
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 Ltd
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 Ltd