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]
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.
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]
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.
Welcome to Dr. Vijaikumar Sakthivel who joined as a Research Fellow in AESL.
An article titled “Communication—Mg(TFSI)2-Based Hybrid Magnesium-Sodium Electrolyte: Case Study with NaTi2(PO4)3//Mg Cell” authored by A. Rudola, S.A.B. Azmansah, and P. Balaya, has been accepted for publication in Journal of The Electrochemical Society. [DOI: 10.1149/2.1091805jes]
Currently, only two types of hybrid Mg-Na electrolytes are known. Herein, we report a new hybrid Mg-Na electrolyte, based on Mg(TFSI)2 and NaBF4 salts in diglyme solvent, which engenders non-dendritic cycling of Mg metal when used in hybrid Mg-Na cells. Using NaTi2(PO4)3 as sodium intercalation-type cathode, NaTi2(PO4)3/C vs Mg cell delivered discharge capacity approaching 120 mAh/g with flat plateau at 1.25 V vs Mg/Mg2+, along with relatively good rate performance and cycling stability.
An article titled “NASICON-type La3+substituted LiZr2(PO4)3 with improved ionic conductivity as solid electrolyte” authored by V. Ramar, S. Kumar, S.R. Sivakkumar and P. Balaya, has been accepted for publication in Electrochimica Acta. [DOI: 10.1016/j.electacta.2018.03.115]
NASICON-structured Li1+xZr2-xLax(PO4)3 (x = 0–0.2) solid electrolytes are prepared by sol-gel method. The influence of substitution of La3+ for Zr4+ on the ionic conductivity, morphology, and structure of the parent compound LiZr2(PO4)3 (LZP) is investigated. Rietveld refinement of powder x-ray diffraction data reveals that the La3+ substitution stabilizes the LZP in the highly conducting rhombohedral Rc phase at room temperature. La3+ substituted LZP display enhanced ionic conductivity, showing the highest ionic conductivity of 0.72 × 10−4 S/cm at room temperature for the composition Li1.1Zr1.9La0.1(PO4)3. The improvement in conductivity of LZP with another aliovalent substituent, Mg2+, whose ionic radii is similar to Zr4+ (0.72 Å) is also investigated. Further, the activation energy decreases from 0.53 eV for the parent LZP to 0.42 eV for x = 0.1 La3+ substituted LZP. Lithium-ion transference number obtained by direct current polarization for Li1.1Zr1.9La0.1(PO4)3 is 0.99, confirming the high ionic conducting nature of the solid electrolyte. Cyclic voltammetry recorded for Li1.1Zr1.9La0.1(PO4)3 shows electrochemical stability window up to ∼4.0 V vs. Li. In particular, La3+ substituted NASICON-type LZP (x = 0.1) exhibits good chemical and structural stability after exposing to air, water, Li metal, acidic and basic solutions.
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