Browsing by Author "Sukumaran, Gopukumar"

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BI2S3 NANORODS DEPOSITED ON REDUCED GRAPHENE OXIDE FOR POTASSIUM-ION BATTERIES
(ACS Publications, 2023-03-21) Chandrasekaran, Nithya; Jeevan Kumar, Reddy Modigunta; Insik, In; Soye, Kim; Sukumaran, Gopukumar
Hierarchical nanocomposites with surface active bonding features serve as an efficient electrode material for high-performance Li-/Na-/K-ion batteries. Tuning the physiochemical properties of these hierarchical nanocomposites has a great impact on the extremely improved electrochemical performance, and it is attributed to the synergistic effect of heterogeneous components. Herein, we report a hydrothermally synthesized bismuth sulfide (Bi2S3) nanorod bonding on the surface of the reduced graphene oxide (rGO) matrix and investigate it as an anode material for potassium-ion batteries. This hierarchical nanocomposite anode exhibits a high initial reversible capacity (586 mA h g–1 at 100 mA g–1), long-term cycling stability (410 mA h g–1 after 1000 cycles, 70% capacity retention), and an outstanding rate capability (140 mA h g–1 at 3 A g–1). This excellent electrochemical performance of the Bi2S3/rGO nanocomposite is attributed to the presence of active sites in rGO nanosheets that not only enhances the electrical conductivity of Bi2S3 nanorods but also prevents the shuttle effect of polysulfide through the formation of the in-built C–S bond, which is confirmed by X-ray photoelectron spectroscopy. Through the ex-situ X-ray diffraction patterns analysis at different voltage regions, a phase transformation mechanism has been proposed for K-ion storage in Bi2S3 nanorods. An ex-situ high-resolution transmission electron microscopy analysis reveals the structural and morphological stability of Bi2S3 nanorods. Further, the kinetic studies confirmed that the surface dominated pseudocapacitive K-ion storage also plays a major role in improving the electrochemical performance of the Bi2S3 nanorods/rGO nanocomposite. The K-ion full cell is successfully assembled, which exhibits stable cycling performance after 100 cycles at 1 C rate.
BI2S3 NANORODS DEPOSITED ON REDUCED GRAPHENE OXIDE FOR POTASSIUM-ION BATTERIES
(2023-03-21) Chandrasekaran, Nithya; Jeevan, Kumar Reddy Modigunta; Insik, In; Soye, Kim; Sukumaran, Gopukumar
Hierarchical nanocomposites with surface active bonding features serve as an efficient electrode material for high-performance Li-/Na-/K-ion batteries. Tuning the physiochemical properties of these hierarchical nanocomposites has a great impact on the extremely improved electrochemical performance, and it is attributed to the synergistic effect of heterogeneous components. Herein, we report a hydrothermally synthesized bismuth sulfide (Bi2S3) nanorod bonding on the surface of the reduced graphene oxide (rGO) matrix and investigate it as an anode material for potassium-ion batteries. This hierarchical nanocomposite anode exhibits a high initial reversible capacity (586 mA h g–1 at 100 mA g–1), long-term cycling stability (410 mA h g–1 after 1000 cycles, 70% capacity retention), and an outstanding rate capability (140 mA h g–1 at 3 A g–1). This excellent electrochemical performance of the Bi2S3/rGO nanocomposite is attributed to the presence of active sites in rGO nanosheets that not only enhances the electrical conductivity of Bi2S3 nanorods but also prevents the shuttle effect of polysulfide through the formation of the in-built C–S bond, which is confirmed by X-ray photoelectron spectroscopy. Through the ex-situ X-ray diffraction patterns analysis at different voltage regions, a phase transformation mechanism has been proposed for K-ion storage in Bi2S3 nanorods. An ex-situ high-resolution transmission electron microscopy analysis reveals the structural and morphological stability of Bi2S3 nanorods. Further, the kinetic studies confirmed that the surface dominated pseudocapacitive K-ion storage also plays a major role in improving the electrochemical performance of the Bi2S3 nanorods/rGO nanocomposite. The K-ion full cell is successfully assembled, which exhibits stable cycling performance after 100 cycles at 1 C rate.
HIGH-PERFORMING LIMGXCUYCO1−X−YO2 CATHODE MATERIAL FOR LITHIUM RECHARGEABLE BATTERIES
(American Chemical Society, 2012-08-22) Chandrasekaran, Nithya; Ramasamy, Thirunakaran; Arumugam, Sivashanmugam; Sukumaran, Gopukumar
Sustainable power requirements of multifarious portable electronic applications demand the development of high energy and high power density cathode materials for lithium ion batteries. This paper reports a method for rapid synthesis of a cobalt based layered cathode material doped with mixed dopants Cu and Mg. The cathode material exhibits ordered layered structure and delivers discharge capacity of ∼200 mA h g–1 at 0.2C rate with high capacity retention of 88% over the investigated 100 cycles.
LICOXMN1-XPO4/C – A HIGH PERFORMING NANO COMPOSITE CATHODE MATERIAL FOR LITHIUM RECHARGEABLE BATTERIES
(WILEY‐VCH Verlag, 2012-12-01) Chandrasekaran, Nithya; Ramasamy, Thirunakaran; Arumugam, Sivashanmugam; Sukumaran, Gopukumar
Pristine and Co‐doped LiMnPO4 have been synthesized by the sol‐gel method using glycine as a chelating agent and the carbon composites were obtained by the wet ball mill method. The advantage of this method is that it does not require an inert atmosphere (economically viable) and facilitates a shorter time for synthesis. The LiCo0.09Mn0.91PO4/C nanocomposites exhibit the highest coulombic efficiency of 99 %, delivering a capacity of approximately 160 mAhg−1 and retain a capacity of 96.3 % over the investigated 50 cycles when cycled between 3–4.9 V at a charge/discharge rate of 0.1 C.
LICOXMN1-XPO4/C: A HIGH PERFORMING NANOCOMPOSITE CATHODE MATERIAL FOR LITHIUM RECHARGEABLE BATTERIES
(An Asian Journal, 2011-10-14) Chandrasekaran, Nithya; Ramasamy, Thirunakaran; Arumugam, Sivashanmugam; Sukumaran, Gopukumar
Pristine and Co-doped LiMnPO4 have been synthesized by the sol-gel method using glycine as a chelating agent and the carbon composites were obtained by the wet ball mill method. The advantage of this method is that it does not require an inert atmosphere (economically viable) and facilitates a shorter time for synthesis. The LiCo0.09Mn0.91PO4/C nanocomposites exhibit the highest coulombic efficiency of 99 %, delivering a capacity of approximately 160 mAhg−1 and retain a capacity of 96.3 % over the investigated 50 cycles when cycled between 3–4.9 V at a charge/discharge rate of 0.1 C.
A MN3O4 NANOSPHERES@RGO ARCHITECTURE WITH CAPACITIVE EFFECTS ON HIGH POTASSIUM STORAGE CAPABILITY
(Royal Society of Chemistry, 2019-09-10) Chandrasekaran, Nithya; Palanivelu, Vishnuprakash; Sukumaran, Gopukumar
A two dimensional (2D) Mn3O4@rGO architecture has been investigated as an anode material for potassium-ion secondary batteries. Herein, we report the synthesis of a Mn3O4@rGO nanocomposite and its potassium storage properties. The strong synergistic interaction between high surface area reduced graphene oxide (rGO) sheets and Mn3O4 nanospheres not only enhances the potassium storage capacity but also improves the reaction kinetics by offering an increased electrode/electrolyte contact area and consequently reduces the ion/electron transport resistance. Spherical Mn3O4 nanospheres with a size of 30–60 nm anchored on the surface of rGO sheets deliver a high potassium storage capacity of 802 mA h g−1 at a current density of 0.1 A g−1 along with superior rate capability even at 10 A g−1 (delivers 95 mA h g−1) and cycling stability. A reversible potassium storage capacity of 635 mA h g−1 is retained (90%) after 500 cycles even at a high current density of 0.5 A g−1. Moreover, the spherical Mn3O4@rGO architecture not only offers facile potassium ion diffusion into the bulk but also contributes surface K+ ion storage. The obtained results demonstrate that the 2D spherical Mn3O4@rGO nanocomposite is a promising anode architecture for high performance KIBs.
A MN3O4 NANOSPHERES@RGO ARCHITECTURE WITH CAPACITIVE EFFECTS ON HIGH POTASSIUM STORAGE CAPABILITY
(The Royal Society of Chemistry, 2019-11) Chandrasekaran, Nithya; Palanivelu, Vishnuprakash; Sukumaran, Gopukumar
A two dimensional (2D) Mn3O4@rGO architecture has been investigated as an anode material for potassium-ion secondary batteries. Herein, we report the synthesis of a Mn3O4@rGO nanocomposite and its potassium storage properties. The strong synergistic interaction between high surface area reduced graphene oxide (rGO) sheets and Mn3O4 nanospheres not only enhances the potassium storage capacity but also improves the reaction kinetics by offering an increased electrode/electrolyte contact area and consequently reduces the ion/electron transport resistance. Spherical Mn3O4 nanospheres with a size of 30-60 nm anchored on the surface of rGO sheets deliver a high potassium storage capacity of 802 mA h g-1 at a current density of 0.1 A g-1 along with superior rate capability even at 10 A g-1 (delivers 95 mA h g-1) and cycling stability. A reversible potassium storage capacity of 635 mA h g-1 is retained (90%) after 500 cycles even at a high current density of 0.5 A g-1. Moreover, the spherical Mn3O4@rGO architecture not only offers facile potassium ion diffusion into the bulk but also contributes surface K+ ion storage. The obtained results demonstrate that the 2D spherical Mn3O4@rGO nanocomposite is a promising anode architecture for high performance KIBs.
NOVEL LI4TI5O12/SN NANO-COMPOSITES AS ANODE MATERIAL FOR LITHIUM ION BATTERIES
(Elsevier, 2011-04) Arumugam, Sivashanmugam; Sukumaran, Gopukumar; Ramasamy, Thirunakaran; Chandrasekaran, Nithya; Shanmuga, Prema
Li4Ti5O12/Sn nano-composites have been prepared as anode material for lithium ion batteries by high-energy mechanical milling method. Structure of the samples has been characterized by X-ray diffraction (XRD), which reveals the formation of phase-pure materials. Scanning electron microscope (SEM) and transmission electron microscope (TEM) suggests that the primary particles are around 100 nm size. The local environment of the metal cations is confirmed by Fourier transform infrared (FT-IR) and the X-ray photoelectron spectroscopy (XPS) confirms that titanium is present in Ti4+ state. The electrochemical properties have been evaluated by galvanostatic charge/discharge studies. Li4Ti5O12/Sn–10% composite delivers stable and enhanced discharge capacity of 200 mAh g−1 indicates that the electrochemical performance of Li4Ti5O12/Sn nano-composites is associated with the size and distribution of the Sn particles in the Li4Ti5O12 matrix. The smaller the size and more homogeneous dispersion of Sn particles in the Li4Ti5O12 matrix exhibits better cycling performance of Li4Ti5O12/Sn composites as compared to bare Li4Ti5O12 and Sn particles. Further, Li4Ti5O12 provides a facile microstructure to fairly accommodate the volume expansion during the alloying and dealloying of Sn with lithium.
NOVEL LI4TI5O12/SNNANO-COMPOSITES AS ANODE MATERIAL FOR LITHIUM ION BATTERIES
(Elsevier, 2011-04-01) Arumugam, Sivashanmugam; Sukumaran, Gopukumar; Ramasamy, Thirunakaran; Chandrasekaran, Nithya; ShanmugaPrema
Li4Ti5O12/Snnano-composites have been prepared as anode material for lithium ion batteries by high-energy mechanical milling method. Structure of the samples has been characterized by X-ray diffraction (XRD), which reveals the formation of phase-pure materials. Scanning electron microscope (SEM) and transmission electron microscope (TEM) suggests that the primary particles are around 100 nm size. The local environment of the metal cations is confirmed by Fourier transform infrared (FT-IR) and the X-ray photoelectron spectroscopy (XPS) confirms that titanium is present in Ti4+ state. The electrochemical properties have been evaluated by galvanostatic charge/discharge studies. Li4Ti5O12/Sn–10% composite delivers stable and enhanced discharge capacity of 200 mAh g−1 indicates that the electrochemical performance of Li4Ti5O12/Snnano-composites is associated with the size and distribution of the Sn particles in the Li4Ti5O12 matrix. The smaller the size and more homogeneous dispersion of Sn particles in the Li4Ti5O12 matrix exhibits better cycling performance of Li4Ti5O12/Sn composites as compared to bare Li4Ti5O12 and Sn particles. Further, Li4Ti5O12 provides a facile microstructure to fairly accommodate the volume expansion during the alloying and dealloying of Sn with lithium.
REDUCED GRAPHITE OXIDE/NANO SN: A SUPERIOR COMPOSITE ANODE MATERIAL FOR RECHARGEABLE LITHIUM-ION BATTERIES
(European Chemical Society Publishing, 2013-03-19) Chandrasekaran, Nithya; Sukumaran, Gopukumar
The electrochemical performance of reduced graphite oxide (RGO) anchored with nano Sn particles, which are synthesized by a reduction method, is presented. The Sn nanoparticles are uniformly distributed on the surface of the RGO matrix and the size of the particles is approximately 5–10 nm. The uniform distribution effectively accommodates the volume expansion experienced by Sn particles during cycling. The observed electrochemical performance (97 % capacity retention) can be ascribed to the flexible RGO matrix with uniform distribution of Sn particles, which reduces the lithium-ion diffusion path lengths; therefore, the RGO matrix provides more stability to the Sn particles during cycling. Such studies on Sn nanoparticles anchored on RGO matrices have not been reported to date.