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C. K. Subramaniam

Bio: C. K. Subramaniam is an academic researcher from VIT University. The author has contributed to research in topics: Seebeck coefficient & Superconductivity. The author has an hindex of 14, co-authored 48 publications receiving 552 citations. Previous affiliations of C. K. Subramaniam include Victoria University of Wellington & Victoria University, Australia.

Papers
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TL;DR: In this paper, conductivity and thermopower data for polyaniline (PANI) blends with non-conducting polymers, making a comparison with polyacetylene and discussing general models for conduction.

76 citations

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TL;DR: In this article, the temperature dependence of the conductivity and thermoelectric power of conducting polyaniline (PAni) dispersed in PETG copolyester and in poly(methylmethacrylate) (PMMA) was measured.

58 citations

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TL;DR: In this article, the main RandD activities are: (i) to develop a method for the electrode preparation (ii) to enhance platinum utilisation using low platinum loading and (iii) to design multicell stacks.

58 citations

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TL;DR: In this article, composite membranes were prepared by impregnation of porous PTFE membrane with 2.5% Nafion® solution prepared in various solvents, based on their solubility parameters to effectively wet the substrate for obtaining membranes with lower resistances.

47 citations

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TL;DR: In this article, the electrical conductivity and thermoelectric power of polyaniline/PVC blends were measured, and it was shown that the conductivity of the blends is greater at low temperatures than that of the pure polyaniniline sample.
Abstract: The electrical conductivity and thermoelectric power of polyaniline/PVC blends was measured. Surprisingly, the conductivity of the blends is greater at low temperatures than that of the pure polyaniline sample. The conductivity follows approximately an exp(-T -1/2 ) law over a considerable range of temperature, with deviations from this law observed at high temperatures. The thermoelectric power has metallic magnitude, and increases as temperature increases (with positive sign) except at very low temperatures, where negative peaks are observed. Possible models to interpret these observations are mentioned

47 citations


Cited by
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TL;DR: The principles and methods of designing and optimizing electrolytes for ES performance and application are highlighted through a comprehensive analysis of the literature, and challenges in producing high-performing electrolytes are analyzed.
Abstract: Electrolytes have been identified as some of the most influential components in the performance of electrochemical supercapacitors (ESs), which include: electrical double-layer capacitors, pseudocapacitors and hybrid supercapacitors. This paper reviews recent progress in the research and development of ES electrolytes. The electrolytes are classified into several categories, including: aqueous, organic, ionic liquids, solid-state or quasi-solid-state, as well as redox-active electrolytes. Effects of electrolyte properties on ES performance are discussed in detail. The principles and methods of designing and optimizing electrolytes for ES performance and application are highlighted through a comprehensive analysis of the literature. Interaction among the electrolytes, electro-active materials and inactive components (current collectors, binders, and separators) is discussed. The challenges in producing high-performing electrolytes are analyzed. Several possible research directions to overcome these challenges are proposed for future efforts, with the main aim of improving ESs' energy density without sacrificing existing advantages (e.g., a high power density and a long cycle-life) (507 references).

2,480 citations

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TL;DR: In this article, the authors present a review of the current literature concerning the high temperature polymer electrolylyte membrane (PEM) fuel cell, ranging from cell materials to stack and stack testing, and show that only acid doped PBI membranes meet the US DOE (US Department of Energy) targets for high temperature membranes operating under no humidification on both anode and cathode sides.

725 citations

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TL;DR: In this paper, a review of recent theoretical advances in the study of granular metals is presented, emphasizing the interplay of disorder, quantum effects, fluctuations, and effects of confinement.
Abstract: Granular metals are arrays of metallic particles of a size ranging usually from a few to hundreds of nanometers embedded into an insulating matrix. Metallic granules are often viewed as artificial atoms. Accordingly, granular arrays can be treated as artificial solids with programmable electronic properties. The ease of adjusting electronic properties of granular metals assures them an important role for nanotechnological applications and makes them most suitable for fundamental studies of disordered solids. This review discusses recent theoretical advances in the study of granular metals, emphasizing the interplay of disorder, quantum effects, fluctuations, and effects of confinement. These key elements are quantified by the tunneling conductance between granules $g$, the charging energy of a single granule ${E}_{c}$, the mean level spacing within a granule $\ensuremath{\delta}$, and the mean electronic lifetime within the granule $\ensuremath{\hbar}∕g\ensuremath{\delta}$. By tuning the coupling between granules the system can be made either a good metal for $gg{g}_{c}=(1∕2\ensuremath{\pi}d)\mathrm{ln}({E}_{c}∕\ensuremath{\delta})$ ($d$ is the system dimensionality), or an insulator for $gl{g}_{c}$. The metallic phase in its turn is governed by the characteristic energy $\ensuremath{\Gamma}=g\ensuremath{\delta}$: at high temperatures $Tg\ensuremath{\Gamma}$ the resistivity exhibits universal logarithmic temperature behavior specific to granular materials, while at $Tl\ensuremath{\Gamma}$ the transport properties are those generic for all disordered metals. In the insulator phase the transport exhibits a variety of activation behaviors including the long-puzzling $\ensuremath{\sigma}\ensuremath{\sim}\mathrm{exp}[\ensuremath{-}({T}_{0}∕T{)}^{1∕2}]$ hopping conductivity. Superconductivity adds to the richness of the observed phases via one more energy parameter $\ensuremath{\Delta}$. Using a wide range of recently developed theoretical approaches, it is possible to obtain a detailed understanding of the electronic transport and thermodynamic properties of granular materials, as is required for their applications.

544 citations

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TL;DR: This review reviews existing and emerging binders, binding technology used in energy-storage devices, and state-of-the-art mechanical characterization and computational methods for binder research, and proposes prospective next-generation binders for energy- storage devices from the molecular level to the macro level.
Abstract: Tremendous efforts have been devoted to the development of electrode materials, electrolytes, and separators of energy-storage devices to address the fundamental needs of emerging technologies such as electric vehicles, artificial intelligence, and virtual reality. However, binders, as an important component of energy-storage devices, are yet to receive similar attention. Polyvinylidene fluoride (PVDF) has been the dominant binder in the battery industry for decades despite several well-recognized drawbacks, i.e., limited binding strength due to the lack of chemical bonds with electroactive materials, insufficient mechanical properties, and low electronic and lithium-ion conductivities. The limited binding function cannot meet inherent demands of emerging electrode materials with high capacities such as silicon anodes and sulfur cathodes. To address these concerns, in this review we divide the binding between active materials and binders into two major mechanisms: mechanical interlocking and interfacial b...

505 citations

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TL;DR: In this paper, generalized approaches for the preparation of polyaniline materials are reviewed, focusing on features that determine properties of the final composites/blends, and two distinct groups of synthetic methods based on aniline polymerization either (1) in the presence of or inside a matrix polymer or (2) the blending of a previously prepared PANI with a matrix polymers.

398 citations