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Nickel-titanium oxide as a novel anode material for rechargeable sodium-ion batteries
Kalubarme, R.,Inamdar, A.,Bhange, D. S.,Im, H.,Gosavi, S.,Park, C. J. Royal Society of Chemistry 2016 Journal of Materials Chemistry A Vol.4 No.44
<P>Nickel-titanium oxide (NiTiO3; NTO) of an ilmenite structure that comprises a layered transition-metal octahedral structure, wherein the zigzag open tunnels are possible routes for Na intercalation, can be a potential anode material for sodium (Na) ion batteries (SIBs). In this study, nanocrystalline NTO particles that are of sizes 3 to 5 nm were prepared using a simple hydrothermal process followed by annealing, and the particles were then tested for SIB applications. The pure-NTO electrode that comprises a hexagonal crystal structure and mesoporous morphology demonstrated a reversible capacity of approximately 521 mA h g(-1) that corresponds to a coulombic efficiency of 67% in the first cycle, which further improved to similar to 98% in the following cycles, at an applied specific current of 50 mA g(-1), and stable cycling performance for 200 cycles. Further, due to the synergetic effect of the porous network structure and high surface area, the NTO electrode exhibited an exceptional rate capability, delivering a capacity of 192 mA h g(-1) at a high specific current of 4000 mA g(-1). The excellent cyclability and rate capability of the NTO electrode are attributed to the improved electronic conductivity and highly porous microstructure of the NTO material, whereby fast charge transfer and facile diffusion of the Na-ions to the active sites are enabled.</P>
Kalubarme, Ramchandra S.,Park, Ga-Eun,Jung, Kyu-Nam,Shin, Kyoung-Hee,Ryu, Won-Hee,Park, Chan-Jin The Electrochemical Society 2014 Journal of the Electrochemical Society Vol.161 No.6
<P>The oxygen electrode is a vital element in developing lithium-oxygen batteries, because it provides the active sites for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In addition, the performance of the oxygen electrode strongly depends on the activity and architecture of materials employed. Perovskite oxide nanostructures of nickel-doped lanthanum cobaltite were prepared by a very simple and cost-effective solution combustion synthesis. The oxygen electrode containing a carbon-supported perovskite oxide catalyst with oxygen vacancies exhibited reduced polarization and improved discharge capacity compared with that containing only bare carbon without a catalyst. In particular, the LaNi<SUB>0.25</SUB>Co<SUB>0.75</SUB>O<SUB>3-δ</SUB> catalyst showed the best catalytic activity for OER by achieving the oxidation of Li<SUB>2</SUB>O<SUB>2</SUB> at 3.8 V. The widespread dispersion and mesoporous design of perovskite facilitates the diffusion of electrolyte and oxygen into the inner electrode to demonstrate cyclability for 49 cycles while maintaining a moderate specific capacity of 1000 mAh g<SUP>−1</SUP>. Further, the synergistic effect of the fast kinetics of electron transport provided by the carbon support and the high electro-catalytic activity of the perovskite oxide resulted in excellent performance of the oxygen electrode for Li-O<SUB>2</SUB> batteries.</P>
Kalubarme, Ramchandra S,Kim, Yong-Han,Park, Chan-Jin IOP Pub 2013 Nanotechnology Vol.24 No.36
<P>A carbon nanotube (CNT)/cerium oxide composite was prepared by a one-pot hydrothermal reaction in the presence of KOH and capping agent polyvinylpyrrolidone. The nanocomposite displayed pronounced capacitive behaviour with very small diffusion resistance. The electrochemical performance of the composite electrode in a symmetric supercapacitor displayed a high energy density of 35.9 Wh kg<SUP>−1</SUP> corresponding to a specific capacitance of 289 F g<SUP>−1</SUP>. These composite electrodes also demonstrated a long cycle life with better capacity retention.</P>
Kalubarme, Ramchandra S.,Lee, Jae-Young,Park, Chan-Jin American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.31
<P>The major obstacle in realizing sodium (Na)-ion batteries (NIBs) is the absence of suitable negative electrodes. This is because graphite, a commercially well known anode material for lithium-ion batteries, cannot be utilized as an insertion host for Na ions due to its large ionic size. In this study, a simple and cost-effective hydrothermal method to prepare carbon coated tin oxide (SnO<SUB>2</SUB>) nanostructures as an efficient anode material for NIBs was reported as a function of the solvent used. A single phase SnO<SUB>2</SUB> resulted for the ethanol solvent, while a blend of SnO and SnO<SUB>2</SUB> resulted for the DI water and ethylene glycol solvents. The elemental mapping in the transmission electron microscopy confirmed the presence of carbon coating on the SnO<SUB>2</SUB> nanoparticles. In cell tests, the anodes of carbon coated SnO<SUB>2</SUB> prepared in ethanol solvent exhibited stable cycling performance and attained a capacity of about 514 mAh g<SUP>–1</SUP> on the first charge. With the help of the conductive carbon coating, the SnO<SUB>2</SUB> delivers more capacity at high rates: 304 mAh g<SUP>–1</SUP> at the 1 C rate, 213 mAh g<SUP>–1</SUP> at the 2 C rate and 133 mAh g<SUP>–1</SUP> at the 5 C rate. The excellent cyclability and high rate capability are the result of the formation of a mixed conducting network and uniform carbon coating on the SnO<SUB>2</SUB> nanoparticles.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-31/acsami.5b04178/production/images/medium/am-2015-04178y_0017.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b04178'>ACS Electronic Supporting Info</A></P>
Ceria based catalyst for cathode in non-aqueous electrolyte based Li/O<sub>2</sub> batteries
Kalubarme, Ramchandra S,Cho, Min-Seung,Kim, Jae-Kook,Park, Chan-Jin IOP Pub 2012 Nanotechnology Vol.23 No.43
<P>This study suggests combustion synthesized Ce<SUB>1−x</SUB>Zr<SUB>x</SUB>O<SUB>2</SUB> (CZO; x = 0.1–0.5) as a new catalyst for the cathode in non-aqueous electrolyte based Li/O<SUB>2</SUB> cells. The spherical catalysts have a fluorite structure with a mean diameter of 5–17 nm. Zr doping into the ceria lattice leads to the reduction of Ce<SUP>4+</SUP> to Ce<SUP>3+</SUP>, which further improves the catalyst performance. Electrochemical studies of CZO as a cathode catalyst in the Li/O<SUB>2</SUB> cell show that CZO follows a two-electron pathway for oxygen reduction. A maximum discharge capacity of 1620 mAh g<SUP>−1</SUP> is obtained for the Ce<SUB>0.8</SUB>Zr<SUB>0.2</SUB>O<SUB>2</SUB> catalyst due to its high surface area and porosity. A composite of CZO and MnO<SUB>2</SUB> shows even better performance as a cathode catalyst for the Li/O<SUB>2</SUB> cell. </P>
Inamdar, A.,Kalubarme, R.,Kim, J.,Jo, Y.,Woo, H.,Cho, S.,Pawar, S. M.,Park, C. J.,Lee, Y. W.,Sohn, J. Royal Society of Chemistry 2016 Journal of materials chemistry. A, Materials for e Vol.4 No.13
<P>We demonstrate the impressive performance of sparsely studied nickel titanate anode materials for Li-ion batteries (LIBs). The nickel titanate anode delivers a high reversible discharge capacity of 435 mA h g(-1) at a current density of 35 mA g(-1), high-rate performance and excellent cycling retention of 96% with a long-term cycling stability at 1500 mA g(-1) over 300 cycles. The coulombic efficiency is obtained as high as 98%. This superior nickel titanate electrode material could be used as a safe, low-cost, long cycle life anode material for next-generation LIBs with a high power capability.</P>
Ngo, Duc Tung,Kalubarme, Ramchandra S,Le, Hang T T,Park, Choong-Nyeon,Park, Chan-Jin RSC Pub 2015 Nanoscale Vol.7 No.6
<P>In this study, a novel method has been proposed for synthesizing amorphous GeO2/C composites. The amorphous GeO2/C composite without carbon black as an electrode for Li-ion batteries exhibited a high specific capacity of 914 mA h g(-1) at the rate of C/2 and enhanced rate capability. The amorphous GeO2/C electrode exhibited excellent electrochemical stability with a 95.3% charge capacity retention after 400 charge-discharge cycles, even at a high current charge-discharge of C/2. Furthermore, a full cell employing the GeO2/C anode and the LiCoO2 cathode displayed outstanding cycling performance. The superior performance of the GeO2/C electrode enables the amorphous GeO2/C to be a potential anode material for secondary Li-ion batteries.</P>
Kale, Sayali B.,Kalubarme, Ramchandra S.,Mahadadalkar, Manjiri A.,Jadhav, Harsharaj S.,Bhirud, Ashwini P.,Ambekar, Jalinder D.,Park, Chan-Jin,Kale, Bharat B. The Royal Society of Chemistry 2015 Physical Chemistry Chemical Physics Vol.17 No.47
<P>Hierarchical 3D ZnIn2S4/graphene (ZnIn2S4/Gr) nano-heterostructures were successfully synthesized using an in-situ hydrothermal method. The dual functionality of these nano-heterostructures i.e. for solar hydrogen production and lithium ion batteries has been demonstrated for the first time. The ZnIn2S4/Gr nano-heterostructures were optimized by varying the concentrations of graphene for utmost hydrogen production. An inspection of the structure shows the existence of layered hexagonal ZnIn2S4 wrapped in graphene. The reduction of graphene oxide (GO) to graphene was confirmed by Raman and XPS analyses. The morphological analysis demonstrated that ultrathin ZnIn2S4 nanopetals are dispersed on graphene sheets. The optical study reveals the extended absorption edge to the visible region due to the presence of graphene and hence is used as a photocatalyst to transform H2S into eco-friendly hydrogen using solar light. The ZnIn2S4/Gr nano-heterostructure that is comprised of graphene and ZnIn2S4 in a weight ratio of 1 : 99 exhibits enhanced photocatalytically stable hydrogen production i.e. B6365 mmole h(-1) under visible light irradiation using just 0.2 g of nano-heterostructure, which is much higher as compared to bare hierarchical 3D ZnIn2(S4). The heightened photocatalytic activity is attributed to the enhanced charge carrier separation due to graphene which acts as an excellent electron collector and transporter. Furthermore, the usage of nano-heterostructures and pristine ZnIn2S4 as anodes in lithium ion batteries confers the charge capacities of 590 and 320 mA h g(-1) after 220 cycles as compared to their initial reversible capacities of 645 and 523 mA h g(-1), respectively. These nano-heterostructures show high reversible capacity, excellent cycling stability, and high-rate capability indicating their potential as promising anode materials for LIBs. The excellent performance is due to the nanostructuring of ZnIn2S4 and the presence of a graphene layer, which works as a channel for the supply of electrons during the charge-discharge process. More significantly, their dual functionality in energy generation and storage is quite unique and commendable.</P>