Kothandaraman Ramanujam

Bio: Kothandaraman Ramanujam is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Catalysis & Chemistry. The author has an hindex of 12, co-authored 67 publications receiving 544 citations. Previous affiliations of Kothandaraman Ramanujam include Michigan State University.

The combined impact of trimethyloctadecylammonium chloride and sodium fluoride on cycle life and energy efficiency of soluble lead-acid flow battery

Abstract: The development and commercialization of SLRFB is obstructed due to its limited cycle life. The cycle life is prevented due to the formation of Pb dendrites, sluggish kinetics of Pb +2 /PbO 2 redox species, partial reversibility of PbO 2 , and O 2 evolution during charging. SLRFB has common electrolyte reservoir, therefore, it is desirable to add both anode and cathode benefitting additives together in the electrolyte. But, such kind of study is very limited in the literature. By considering this, first time, the present work demonstrates the combined effect of trimethyloctadecylammonium chloride and NaF/LiF as electrolyte additives on the electrochemical performance and cycle life of SLRFB. Compared with the pristine electrolyte, the kinetics and reversibility of Pb 2+ /PbO 2 redox couple are improved in the presence of additives. Both Pb and PbO 2 electrodeposits are smooth, compact and uniform in the presence of additives. The lifespan of SLRFB without any additive is limited to 45 charge/discharge cycles due to shorting of the electrodes. The CE has been decreased from 93 % to 74 % in 46th cycles at a charging current density of 20 mA cm 2 . However, in the presence of additives, the cell has been successfully cycled for over 500 cycles with an average CE, VE and EE of 94 %, 78 % and 74 % respectively. The cell also showed the maximum specific capacity 50 mAh cm −2 over 100 cycles when cycled at 50 mA cm 2 current density for 1 h, such high current density operation is very scarce in the literature. • The effect of TMOAC and NaF/LiF on the SLRFB’s performance has been studied first time. • Additives improve the kinetics and influences the Pb and PbO 2 electroplating. • Cycle life of SLRFB extended >500 charge/discharge cycles without requiring maintenance. • The average coulombic and energy efficiency of the cell is 94%, and 74% respectively. • Cell showed the highest areal capacity of 50 mAh cm -2 for >50 cycles @ 50 mA cm 2 current density.

Machine Learning enabled High-Throughput Screening of Inorganic Solid Electrolytes for Regulating Dendritic Growth in Lithium Metal Anodes

Abstract: The Li-S secondary battery system has gained popularity owing to their advantage of higher specific energy compared to the Li ion battery. However, it suffers majorly due to the Li...

Investigation of Alkyl Amine Substituted Quinone Derivatives for the Redox Flow Battery Applications in Acidic Medium

Abstract: 2,5-bis((dimethylamino)methyl)benzene-1,4-diol (H2QDMA), a redox-active molecule and its derivatives are synthesised by a one-step chemical method using Mannich reaction and studied as a potential catholyte with vanadium (V2+/V3+) anolyte for aqueous redox flow battery applications. The solubility of H2QDMA was ~ 0.75 M in 3 M H2SO4. H2QDMA showed one sharp redox peak at the formal potential 0.6 V ± vs Ag/AgCl, and it was stable for 100 continuous CV cycles without any appreciable change in color. The battery delivered a discharge capacity of ~ 2 Ah L-1, which faded with cycles. We have carried out a post cycle analysis of catholyte and anolyte to understand the origin of the capacity fading. Toward this end, the oxidized form of H2QDMA, i.e., QDMA, was synthesized. The stability of QDMA in acidic solution was low, and the color of the solution changed to intense brown with time. The UV-Visible spectrum and CV curves of the QDMA reflects the same behavior as observed with the catholyte solution obtained post galvanostatic charge-discharge analysis. This study concluded that the QDMA undergoes faster chemical transformation, presumably through the Michael addition reaction process, compared to its participation in the desired electrochemical process.

Recent Advances in Electrocatalysts for Oxygen Reduction Reaction

Abstract: The recent advances in electrocatalysis for oxygen reduction reaction (ORR) for proton exchange membrane fuel cells (PEMFCs) are thoroughly reviewed. This comprehensive Review focuses on the low- and non-platinum electrocatalysts including advanced platinum alloys, core–shell structures, palladium-based catalysts, metal oxides and chalcogenides, carbon-based non-noble metal catalysts, and metal-free catalysts. The recent development of ORR electrocatalysts with novel structures and compositions is highlighted. The understandings of the correlation between the activity and the shape, size, composition, and synthesis method are summarized. For the carbon-based materials, their performance and stability in fuel cells and comparisons with those of platinum are documented. The research directions as well as perspectives on the further development of more active and less expensive electrocatalysts are provided.

Metal–Organic Frameworks in Heterogeneous Catalysis: Recent Progress, New Trends, and Future Perspectives

Abstract: More than 95% (in volume) of all of today’s chemical products are manufactured through catalytic processes, making research into more efficient catalytic materials a thrilling and very dynamic rese...

Molecularly Imprinted Polymers

Abstract: Molecularly imprinted polymers are synthetic receptors for a targeted molecule. As such, they are analogues of the natural antibody–antigen systems. In this review, after a recounting of the early history of the general field, we specifically focus on the application of these polymers as sensors. In these applications, the polymers are paired with a reporting system, which may be electrical, electrochemical, optical, or gravimetric. The presence of the targeted molecule effects a change in the reporting agent, and a calibrated quantity of the target is recorded. In this review, we describe the imprinted polymer production processes, the techniques used for reporting, and the applications of the reported sensors. A brief survey of recent applications to gas-phase sensing is included, but the focus is primarily on the development of sensors for targets in solution. Included among the applications are those designed to detect toxic chemicals, toxins in foods, drugs, explosives, and pathogens. The application...

Nonprecious Metal Catalysts for Oxygen Reduction in Heterogeneous Aqueous Systems

Abstract: A comprehensive review of recent advances in the field of oxygen reduction electrocatalysis utilizing nonprecious metal (NPM) catalysts is presented Progress in the synthesis and characterization of pyrolyzed catalysts, based primarily on the transition metals Fe and Co with sources of N and C, is summarized Several synthetic strategies to improve the catalytic activity for the oxygen reduction reaction (ORR) are highlighted Recent work to explain the active-site structures and the ORR mechanism on pyrolyzed NPM catalysts is discussed Additionally, the recent application of Cu-based catalysts for the ORR is reviewed Suggestions and direction for future research to develop and understand NPM catalysts with enhanced ORR activity are provided

Durability Investigation of Carbon Nanotube as Catalyst Support for Proton Exchange Membrane Fuel Cell Electrode

Abstract: Abstract Electrochemical surface oxidation of carbon black Vulcan XC-72 and multiwalled carbon nanotube (MWNT) has been compared following potentiostatic treatments up to 168 h under condition simulating PEMFC cathode environment (60 °C, N2 purged 0.5 M H2SO4, and a constant potential of 0.9 V). The subsequent electrochemical characterization at different treatment time intervals suggests that MWNT is electrochemically more stable than Vulcan XC-72 with less surface oxide formation and 30% lower corrosion current under the investigated condition. As a result of high corrosion resistance, MWNT shows lower loss of Pt surface area and oxygen reduction reaction activity when used as fuel cell catalyst support.