P VISHNU KAMATH
Articles written in Bulletin of Materials Science
Volume 40 Issue 3 June 2017 pp 427-434
G K KIRAN TIRUPATHI RAO PENKI N MUNICHANDRAIAH P VISHNU KAMATH
Electrodeposited ZnO coatings suffer severe capacity fading when used as conversion anodes in sealed Li cells. Capacity fading is attributed to (i) the large charge transfer resistance, $R_{\rm ct}$ (300–700 $\Omega$) and (ii) the low Li$^+$ ion diffusion coefficient, D$^+_{\rm Li}$ (10$^{−15}$ to 10$^{−13}$ cm$^2$ s$^{−1}$). The measured value of R$_{\rm ct}$ is nearly 10 times higher and D$^+_{\rm Li}$ 10–100 times lower than the corresponding values for Cu$_2$O, which delivers a stable reversible capacity.
Volume 41 Issue 1 February 2018 Article ID 0026
SHIVANNA MARAPPA P VISHNU KAMATH
NO$^−_2$ and SCN$^−$ are two common small inorganic anions. The former is a common industrial pollutant. Thelatter is linear and is a good mimic for the toxic CN$^−$ ion. The structures of these two anions are refined within the gallery ofthe [Zn–Al]-layered double hydroxide (LDH). Both LDHs crystallize as mixed anion phases. The nitrite is found to co-existwith the nitrate ion. The nitrite ion is intercalated with its molecular plane inclined to the metal hydroxide layer. In the caseof the SCN$^−$ intercalated LDH, no other anion was detected by ion chromatography, suggesting that the SCN$^−$ deficiencyis compensated by intercalated hydroxyl ions. In this case, the SCN$^−$ ion is found to be intercalated with its molecular axisinclined to the metal hydroxide layer.
Volume 43 All articles Published: 15 June 2020 Article ID 0141
LATHA PACHAYAPPAN P VISHNU KAMATH
Imbibition of lithium sulphate into aluminium hydroxide is known to result in a sulphate-intercalated layered double hydroxide (LDH) of Li and Al. The perchlorate ion has the same size and molecular symmetry as the sulphate ion,but only half its charge. Consequently, twice the number of ClO$^−_4$ ions is needed to balance LDHs the charge on the metal hydroxide layer, compared to the SO$^{2−}_4$ ions. In this work, the ClO$^−_4$-intercalated LDHs were obtained from both the bayerite and gibbsite precursors. Inclusion of the hydration sphere along with the ClO$^−_4$ anion, induced turbostratic disorder in the stacking of the metal hydroxide layers. Temperature-induced dehydration ($T \sim 100$–140$^{\circ}$C) brought about a partial ordering in the interlayer region and the ClO$^−_4$ ion oriented itself with one of its $C_2$-axes parallel to the metal hydroxide layer. The close packing of ClO$^−_4$ ions could be realized by the complete dehydration of LDH and the distribution of the ClO$^−_4$ ions in all the available interlayer sites. In contrast, within the crystal of the sulphate analogue, the sulphate ions occupy only half the number of interlayer sites. The other half is occupied by the residual water molecules, as the sulphate analogue does not fully dehydrate even at elevated temperatures. This difference in the behaviour of the two LDHs has its origin in the largedifference in the hydration enthalpies of the two anions.
Volume 43, 2020
All articles
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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