ORCID Profile
0000-0001-5905-2997
Current Organisation
UNSW Sydney
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Publisher: American Chemical Society (ACS)
Date: 13-02-2023
Publisher: IOP Publishing
Date: 05-10-2020
Abstract: Innovative applications based on two-dimensional solids require cost-effective fabrication processes resulting in large areas of high quality materials. Chemical vapour deposition is among the most promising methods to fulfill these requirements. However, for 2D materials prepared in this way it is generally assumed that they are of inferior quality in comparison to the exfoliated 2D materials commonly used in basic research. In this work we challenge this assumption and aim to quantify the differences in quality for the prototypical transition metal dichalcogenide MoS 2 . To this end single layers of MoS 2 prepared by different techniques (exfoliation, grown by different chemical vapour deposition methods, transfer techniques and as vertical heterostructure with graphene) are studied by Raman and photoluminescence spectroscopy, complemented by atomic force microscopy. We demonstrate that as-prepared MoS 2 , directly grown on SiO 2 , differs from exfoliated MoS 2 in terms of higher photoluminescence, lower electron concentration and increased strain. As soon as a water film is intercalated (e.g. by transfer) underneath the grown MoS 2 , in particular the (opto)electronic properties become practically identical to those of exfoliated MoS 2 . A comparison of the two most common precursors shows that the growth with MoO 3 causes greater strain and/or defect density deviations than growth with ammonium heptamolybdate. As part of a heterostructure directly grown MoS 2 interacts much stronger with the substrate and in this case an intercalated water film does not lead to the complete decoupling, which is typical for exfoliation or transfer. Our work shows that the supposedly poorer quality of grown 2D transition metal dichalcogenides is indeed a misconception.
Publisher: Elsevier BV
Date: 08-2018
Publisher: The Electrochemical Society
Date: 2023
Abstract: Carbon-based cathode materials play a crucial role in the development of alternative battery technologies. For lithium-sulfur batteries, carbonaceous S-hosts and carbon-sulfur copolymers have been reliably used as cathode materials to improve battery cyclability and working lifetimes. Characterizing these carbon-based materials in their as-prepared state, when fabricated into cathodes, and during electrochemical function requires the use of multiple complementary techniques probing various length scales, e.g., atomic, nanometer, micrometer. Appropriate coupling of characterization techniques and interpretation of data allows researchers to accurately establish the relationship between composition, structure, and property, which in turn facilitates rational design of complex materials. These combined strategies have provided some of the most detailed insights surrounding the role and design of carbon-based materials to date. This review covers some of the ways both conventional and emerging analytical techniques have been used by researchers to investigate carbon-based cathode materials for Li-S batteries.
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3CP02030D
Abstract: Batteries play an increasingly critical role in the functioning of contemporary society. This work illustrates a new family of electrode materials and an alternative method to produce the electrode for applications.
Publisher: American Chemical Society (ACS)
Date: 14-05-2019
Publisher: American Chemical Society (ACS)
Date: 04-01-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8RA03156H
Abstract: This review article outlines a comparison of GO and r-GO membranes for separation and purification applications.
Publisher: Wiley
Date: 06-11-2021
Abstract: Since the commercialization of lithium‐ion batteries, graphite has been the uncontested material of choice as the negative electrode host structure, and it has therefore been pivotal for their ubiquitous adoption and implementation. Despite extensive research efforts dedicated to discovering and developing alternative anode material candidates, no commercially viable successor has so‐far been identified. Simultaneously, the understanding of graphite electrode function is continuously expanding, and new strategies for rationally improving performance are being explored. Here, the key challenges lie in examining the graphitic material, not only in the pure as‐prepared state, but also when formed into an electrode and during electrochemical cycling, i.e., in situ/operando. A multiscale approach is necessary to accurately relate the (de)lithiation/(de)intercalation mechanisms involved to the observed performance. The present review summarizes conventional techniques and highlights recent advances in the analytical methods used for the characterization of graphite‐based electrode structure and function. The discussion is based on ex les from key recent work using innovative analytical strategies to obtain novel insight into the evolution in structure, microstructure, electronic structure, surface chemistry/composition, etc. The deeper understanding of material function gained from these innovative approaches may hold the key for the rational design of next‐generation graphite‐based or ‐inspired electrodes.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Elsevier BV
Date: 08-2017
Publisher: American Chemical Society (ACS)
Date: 16-08-2018
Publisher: American Chemical Society (ACS)
Date: 02-11-2022
Abstract: Liquid metals can be surface activated to generate a controlled galvanic potential by immersing them in aqueous solutions. This creates energized liquid-liquid interfaces that can promote interfacial chemical reactions. Here we utilize this interfacial phenomenon of liquid metals to deposit thin films of tin-doped tellurium onto rigid and flexible substrates. This is accomplished by exposing liquid metals to a precursor solution of Sn
Publisher: Elsevier BV
Date: 08-2018
Publisher: American Chemical Society (ACS)
Date: 07-11-2017
Publisher: IOP Publishing
Date: 16-09-2022
Abstract: Practical utilisation of renewable energy from intermittent sustainable sources such as solar and wind relies on safe, reliable, cost-effective, and high-capacity energy storage systems to be incorporated into the grid. Among the most promising technologies aimed towards this application are sodium-ion batteries(SIBs). Currently, hard carbon is the leading negative electrode material for SIBs given its relatively good electrochemical performance and low cost. Furthermore, hard carbon can be produced from a erse range of readily available waste and renewable biomass sources making this an ideal material for the circular economy. In facilitating future developments on the use of hard carbon-based electrode materials for SIBs, this review curates several analytical techniques that have been useful in providing structure-property insight and stresses the need for overall assessment to be based on a combination of complementary techniques. It also emphasises several key challenges in the characterisation of hard carbons and how various in situ and operando techniques can help unravel those challenges by providing us with a better understanding of these systems during operation thereby allowing us to design high-performance hard carbon materials for next-generation batteries.
Publisher: Springer International Publishing
Date: 2016
Publisher: Springer International Publishing
Date: 2016
No related grants have been discovered for Uttam Mittal.