Professor Palani Balaya received the injection certificate as Academician by the World Academy of Ceramics (WAC) from the President of WAC, Dr. Mrityunjay Singh from NASA Glenn Research Centre, USA during CIMTEC2022 Conference at Perugia, Italy on 21 June 2022.
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An article titled ” Introducing Na-sufficient P3-Na0.9Fe0.5Mn0.5O2 as cathode material for Na-ion batteries ” authored by Abhinav Tripathi, Shibo Xi, Satyanarayana Reddy Gajjela and Palani Balaya has been accepted for publication in Chemical Communications. [DOI:10.1039/D0CC03701J]
Abstract
P3-Na0.9Fe0.5Mn0.5O2 is reported as a new P-type cathode material for Na-ion batteries. P3 structure can accommodate 0.9 mole of Na-ions leading to high discharge capacity of 155 mAh/g and does not require sacrificial salts for full cell operation. Operando X-ray diffraction studies and ex-situ X-ray absorption studies are also reported.
An article titled ”Analysis of Heat Generation and Impedance Characteristics of Prussian Blue Analogue Cathode-based 18650-type Sodium-ion Cells” authored by L.U. Subasinghe, S.R. Gajjela, A. Rudola, and P. Balaya has been accepted for publication in Journal of The Electrochemical Society. [DOI:10.1149/1945-7111/ab9ee9]
Abstract
We report here 18650-type sodium-ion battery (NIB) with Prussian Blue Analogue Na2Fe2(CN)6 in both monoclinic and rhombohedral phases as the cathode and hard carbon (HC) as the anode using the glyme-based non-flammable 1 mol dm-3 NaBF4 electrolyte. Rhombohedral-Na2Fe2(CN)6 (RPB) vs. HC 18650-type cell delivered an energy density of 43 Wh kg-1, achieving good high rate response up to 4.0 C, stable cycling over 100 cycles with 99.99% average coulombic efficiency and 94.8% average round-trip-energy-efficiency. A comparison of the calorimetric studies performed on 18650-type cells revealed lower heat generation in RPB vs. HC compared to monoclinic-Na2Fe2(CN)6.2H2O (MPB) vs. HC counterpart. Moreover, the RPB vs. HC cell demonstrated lower heat generation than commercial NMC vs. graphite 18650-type lithium-ion cells. Internal resistance, which is the major contributor to heat generation, is assessed by analysing the impedance spectra of the cells. Furthermore, variation in subcomponents of internal resistance across different depths of discharge determined by fitting impedance data using an equivalent circuit model and analysis using distribution of relaxation times (DRT) method is presented for 18650-type sodium-ion cells for the first time. The obtained results indicate that these efficient and safe 18650-type NIBs open-up new opportunities for exploring innovative storage systems for stationary applications.
An article titled ”A Comprehensive Study on the Electrolyte, Anode and Cathode for Developing Commercial Type Non-flammable Sodium-ion Battery” authored by K. Du, C. Wang, L.U. Subasinghe, S.R. Gajjela, M. Law, A. Rudola, and P. Balaya has been accepted for publication in Energy Storage Materials. [DOI: 10.1016/j.ensm.2020.04.021]
Abstract
Here, we present a comprehensive study of choice of electrolyte, anode and cathode to develop commercially viable non-flammable sodium-ion battery. We report hard carbon (HC) vs. Na using ether-based non-flammable electrolyte: 1 M NaBF4 in tetraglyme and compare storage performance, thermal stability and SEI formation with those obtained using carbonate-based electrolyte: 1 M NaClO4 in EC:PC (v:v=1:1). The results shows that 1 M NaBF4 in tetraglyme works as a better electrolyte than carbonate-based electrolyte for HC anode. We present and compare storage performances of pristine and aliovalent-doped Na3V2(PO4)3 (NVP) vs. Na. Doped-NVP outperforms pristine cathode in terms of specific capacity and rate capability. 18650-type non-flammable sodium-ion cells fabricated using modified NVP vs. HC exhibits energy density of 60 Wh kg−1. When discharged at a high rate close to 5 C, the cell successfully retains 83% of its storage capacity obtained at low rate. When cycled at C/5, doped NVP vs. HC 18650 cell retains 90% of its initial capacity after 200 cycles.
An article titled”Developing O3 type layered oxide cathode and its application in 18650 commercial type Na-ion batteries” authored by A. Tripathi, A. Rudola, S.R. Gajjela, S. Xi and P. Balaya, has been accepted for publication in Journal of Materials Chemistry A. [DOI: 10.1039/c9ta08991h]
Abstract
A novel, water-stable and high energy density cathode material Na0.9Cu0.12Ni0.10Fe0.30Mn0.43Ti0.05O2 (NCNFMT) is reported here along with a thorough understanding of structural events during battery operation. Systematic substitutions are carried out, which lead to increase in specific energy densities of this family of cathodes from 274.6 W h kgcathode−1 (NCFM – Na0.9Cu0.22Fe0.30Mn0.48O2) to 304.2 W h kgcathode−1 (NCFMT – Na0.9Cu0.22Fe0.30Mn0.43Ti0.05O2) and finally to 350.7 W h kgcathode−1 (NCNFMT – Na0.9Cu0.12Ni0.10Fe0.30Mn0.43Ti0.05O2). Operando X-ray diffraction reveals phase transformations and ex situ EXAFS shows the evolution of local environments around transition metals during charge/discharge. Monoclinic distortions in the NCFM material during O3–P3 phase transformations are suppressed by Ti4+ substitution leading to improvements in the cycling performance of NCFMT. Cu–O octahedral sites exhibit huge Jahn–Teller distortion: Ni2+ substitution in place of Cu2+ not only leads to more ordered Ni–O, but it also helps extract more Na ions from the O3 cathode structure, thus boosting the capacity while also showing good cycling stability due to the highly reversible bond-length and local environmental changes as revealed by EXAFS analyses. X-ray photoelectron spectroscopy shows a titanium-rich surface for NCFMT and NCNFMT which helps improve water-stability. The capacity retention after 200 cycles at 0.2C is 84%, 96% and 90% for NCFM, NCFMT and NCNFMT respectively. The delivered storage capacities of NCFM, NCFMT and NCNFMT are 21 mA h g−1, 47 mA h g−1 and 60 mA h g−1 respectively at 3C. 18650 type Na-ion batteries using the NCNFMT cathode material against a hard carbon anode are also reported to demonstrate potential scalability of the NCNFMT cathode and efficacy of a 1 M NaBF4 tetraglyme electrolyte system for the first time. 18650 cells deliver a specific energy density of 62 W h kgtotal_18650_weight−1 with 90% energy efficiency, thus being suitable for large scale energy storage applications.
Professor Palani Balaya elected as Fellow of American Ceramic Society (ACerS) in March 2019. Click here for more information.
A/P Palani Balaya gave a keynote speech on “Developing Safe Sodium-Ion Battery Technology for Stationary Storage Applications” in International Battery Association (IBA) 2019 meeting, which was held during 03-08 March 2019, at La Jolla, San Diego, CA.
An article titled “Experimental and theoretical studies of trisodium-1,3,5- benzene tricarboxylate as a low voltage anode material for sodium ion batteries” authored by A. Tripathi, Y. Chen, H. Padhy, S. Manzhos and P. Balaya, has been accepted for publication in Energy Technology. [DOI: 10.1002/ente.201801030]
Abstract
We report a tricarboxylate based organic compound for Na storage at low voltage, trisodium‐1,3,5‐benzene tricarboxylate (Na3BTC). We explore the effect of increasing the number of carboxyl redox active groups on the aromatic system versus previously reported dicarboxylate‐based Na electrodes. Sodiation and de‐sodiation of this material occur at average voltages of 0.4 V and 0.5 V, respectively, suitable for anode application. The galvanostatic profile of de‐sodiation consists of two plateaus at 0.5 V and 0.2 V. The material delivers a capacity of 250 mAh g‐1 at C/5 rate, with retention of 80% after 100 cycles. It also has an excellent rate capability delivering 100 mAh g‐1 with 75% retention after 1,500 cycles at 10 C rate. Ex‐situ ATR‐FTIR, ex‐situ 1H NMR studies as well as first principles calculations are performed to understand the sodium storage mechanism. The mechanism is found to be different from those previously observed in lithium dicarboxylates and sodium dicarboxylates in that there is apparently almost no charge donation from the inserted Na to the organic moiety.
An article titled “Tuning the Capacitance Properties of Nanocrystalline MnCO3 by the Effect of a Carbonizing Agent” authored by P. Vishnu Vardhan, M.B. Idris, H.Y. Liu, S.R. Sivakkumar, P. Balaya, and S. Devaraj, has been accepted for publication in Journal of The Electrochemical Society.
Abstract
Nanocrystalline MnCO3 is synthesized by hydrothermal reduction of KMnO4 using different amounts of pyrrole. The effect of molar ratio of KMnO4:pyrrole on the phase purity, size of the particle, textural and capacitance properties of MnCO3 is studied systematically using various physico-chemical and electrochemical techniques. While X-ray diffraction studies confirm decline in the phase purity of MnCO3, FTIR, Raman spectroscopic and thermogravimetric studies reveal an increase in the amount of adsorbed water and residual carbon content on increasing the pyrrole concentration during the synthesis. An increase in the size of the particles and reduction in the number of mesopores are observed from the morphological and sorption studies on increasing the pyrrole concentration during the synthesis. A highest specific capacitance value of 296 F g−1 is obtained at a current density of 0.16 A g−1 for the nanocrystalline MnCO3, and this capacitance value found to decrease on increasing the concentration of pyrrole during the synthesis of nanocrystalline MnCO3 (166 and 140 F g−1 for the KMnO4:pyrrole ratio of 1:1 and 1:2, respectively).
An article titled “Enhanced electrochemical performance of W incorporated VO2 nanocomposite cathode material for lithium battery application” authored by S.A. Syed Nizar, V .Ramar, T. Venkatesan, P. Balaya, and S. Valiyaveettil, has been accepted for publication in Electrochimica Acta. [DOI: 10.1016/j.electacta.2018.06.076]
Abstract
We report the synthesis, characterization, and performance evaluation of tungsten (W) incorporated vanadium oxide (VO2) nanocomposite cathode material for improved lithium storage performance. VO2 nanorods, 100–200 nm in diameter and 1–3 μm in length are synthesized using a hydrothermal method. W incorporation at different weight percent results in the VO2 morphology shifting from rods to a sheet type structure. The lithium storage performance of VO2 has improved remarkably by increasing the loading of W to an optimal level, which influence the intercalation/ deintercalation of lithium ions into the expanded lattices of VO2. The maximum specific capacity observed for the optimal VO2/W4 composite was 381 mAh/g at a current density of 0.1 C. Cyclic voltammetry measurements showed the presence of an electroactive V3+/V4+ redox couple, leading to lower peak separation and voltage polarization differences. Superior charge storage performance was observed with the VO2/W4 composite as compared to the VO2 based devices.
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