26 research outputs found
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No full textVersion: 1.0.0
Imports: utils, minimalRSD, stats
Published:2017-03-21
Author: Shwetank Lall [aut, cre], Arpan Bhowmik [ctb], Eldho Varghese [aut], Seema Jaggi [ctb], Cini Varghese [ctb]
Maintainer: Shwetank Lall
License: GPL-2 | GPL-3 [expanded from: GPL (≥ 2)]
NeedsCompilation: no
Citation: FMC citation info
In views: ExperimentalDesignAn R package to generate cost effective minimally changed run sequences for symmetrical as well as asymmetrical factorial designsNot Availabl
Investigation of tin and antimony based anodes with enhanced cycle life for sodium-ion batteries
No full textSodium-ion batteries (SIBs) are proposed as a low-cost alternative to the existing lithium-ion batteries (LIBs) in view of the abundance and wide distribution of the sodium reserves.
To realize the practical deployment of the SIBs, however, it is crucial to develop high capacity sodium-storage materials. In this thesis, Sn and Sb based materials have been
explored considering their high capacity, low cost, environmental benignity and safety
aspects. Various scalable, high-throughput and industrially viable synthetic methodologies
including melt-spinning and high-energy ball milling techniques have been employed to
synthesize the active materials. The sodium-storage mechanism, structural and
morphological evolution and transformations in the active materials were probed. The
various strategies adopted in the study could significantly improve the cycle life of the
anodes, which is considered as the Achilles’ heel of alloying and conversion anodes.
Additionally, preliminary full-cell investigations were carried out to gauge the practical
implications and utility of the synthesized anode materials for sodium-ion batteries.
Various novel synthetic methodologies and scientific and technological findings aiding
high energy density sodium-ion batteries based on alloying and conversion anodes were
achieved. The novel insights from the study as well as the proposed future works could
guide and spawn further research and technological advancements towards the practical
deployment of SIBs.Doctor of Philosoph
Melt-spun Fe–Sb intermetallic alloy anode for performance enhanced sodium-ion batteries
No full textOwing to the high theoretical sodiation capacities, intermetallic alloy anodes have attracted considerable interest as electrodes for next-generation sodium-ion batteries (SIBs). Here, we demonstrate the fabrication of intermetallic Fe–Sb alloy anode for SIBs via a high-throughput and industrially viable melt-spinning process. The earth-abundant and low-cost Fe–Sb-based alloy anode exhibits excellent cycling stability with nearly 466 mAh g–1 sodiation capacity at a specific current of 50 mA g–1 with 95% capacity retention after 80 cycles. Moreover, the alloy anode displayed outstanding rate performance with ∼300 mAh g–1 sodiation capacity at 1 A g–1. The crystalline features of the melt-spun fibers aid in the exceptional electrochemical performance of the alloy anode. Further, the feasibility of the alloy anode for real-life applications was demonstrated in a sodium-ion full-cell configuration which could deliver a sodiation capacity of over 300 mAh g–1 (based on anode) at 50 mA g–1 with more than 99% Coulombic efficiency. The results further exhort the prospects of melt-spun alloy anodes to realize fully functional sodium-ion batteries.Accepted versio
Amorphous Vanadium Oxide Thin Films as Stable Performing Cathodes of Lithium and Sodium-Ion Batteries
No full textAbstract Herein, we report additive- and binder-free pristine amorphous vanadium oxide (a-VOx) for Li- and Na-ion battery application. Thin films of a-VOx with a thickness of about 650 nm are grown onto stainless steel substrate from crystalline V2O5 target using pulsed laser deposition (PLD) technique. Under varying oxygen partial pressure (pO2) environment of 0, 6, 13 and 30 Pa, films bear O/V atomic ratios 0.76, 2.13, 2.25 and 2.0, respectively. The films deposited at 6‑30 Pa have a more atomic percentage of V5+ than that of V4+ with a tendency of later state increased as pO2 rises. Amorphous VOx films obtained at moderate pO2 levels are found superior to other counterparts for cathode application in Li- and Na-ion batteries with reversible capacities as high as 300 and 164 mAh g−1 at 0.1 C current rate, respectively. At the end of the 100th cycle, 90% capacity retention is noticed in both cases. The observed cycling trend suggests that more is the (V5+) stoichiometric nature of a-VOx better is the electrochemistry
Beyond intercalation based sodium-ion batteries : role of alloying anodes, efficient sodiation mechanisms and recent progress
No full textSodium-ion batteries (SIBs) have received renewed interest in recent years and are projected as an alternative to the existing lithium-ion battery (LIB) system. Research on SIBs is impelled by the low cost and abundant supply of sodium resources, the similar electrochemistry of SIBs and LIBs and the competing electrochemical performance achieved in recent years. Significant progress has been made in the development of alloying anodes for SIBs which offer high gravimetric and volumetric energy densities when compared to the conventional intercalation based anodes. Recent progress in the field of advanced operando and ex situ characterization techniques as well as theoretical computational studies has shed light on the sodiation mechanism of these alloying anodes. Herein, we review the recent developments in alloying anodes for SIBs. Primarily Sn, Sb, and P based alloying anodes are focused on and the progress in Bi, Ge and Si is also discussed. We focus on the sodiation mechanism of these alloying anodes, recently revealed by means of advanced experimental and computational tools, to enable the design of efficient strategies for enhanced electrochemical performance. We also discuss synthetic methodologies and novel approaches adopted for alloying anodes to mitigate the challenges faced during the (de)sodiation cycles. The future outlook and issues to be addressed to realize the practical implementation of alloying anodes are also discussed.NRF (Natl Research Foundation, S’pore)Accepted versio
Design, Simulation and Comparison of Mixing Schemes for DC, AC and Bidirectional Data through Coaxial Cable
No full textAbstractThis paper deals with the design and simulation of mixing scheme for remote system operation connected through long coaxial cable. The remote system requires mixing of DC, high power AC and high speed data, which enables a cost effective interconnections through a single coaxial cable. Two schemes are proposed for the mixing, one with a relay based switching, in which the high power AC is in short pulsed form and other with passive filters. Simulation study using Multisim and Matlab was carried out for both the schemes. A comparison of these two schemes is also discussed
Highly Stable Intermetallic FeSn<sub>2</sub> -Graphite Composite Anode for Sodium-Ion Batteries
No full textComputational Study of Hypersonic Flow Past Spiked Blunt Body Using RANS and DSMC Method
No full textAbstractHypersonic vehicles when moving at very high speeds experience the problem of drag and heating. One of the ways to reduce this drag and heating is by the use of an aerospike. In the present study, the flow around a blunted body fitted with an aerospike is analyzed using a commercial software ANSYS Fluent and an open source Direct Simulation Monte Carlo (DSMC) code, called as dsmcFoam in OpenFOAM, at a high Mach number (M=6) at different length to diameter ratios (L/D = 1.5, 2) at an angle of attack 0o. The aerospike placed in front of the body replaces the strong detached shock wave ahead of the body with a system of weaker oblique shock waves. A recirculation region is developed between the shock and the blunt body, which acts like a streamlined profile, thus reducing the drag and wall heat flux
Additional file 1: of Amorphous Vanadium Oxide Thin Films as Stable Performing Cathodes of Lithium and Sodium-Ion Batteries
No full textFigure S11. SEM images of bare 304 SS. Figure S12. XRD patterns of a-VOx films deposited under different pO2 conditions in comparison with 304 SS. Figure S13. GC profiles of a-VOx-13Pa (a, b) and a-VOx-30Pa (c, d) at 0.1 C. Figure S14. Li-ion battery CV profile of bare 304 SS at 0.1 mV s−1. Figure S15. Li-ion battery CV (a and c) at 0.1 mV s−1 and GC at 0.1 C profiles of crystalline V2O5 (b and d). Figure S16. Na-ion battery CV profiles about 10 cycles of a-VOx films at 0.1 mV s−1 after 100th GC cycling. (DOCX 1728 kb
