Recent advances in 2D MXenes for enhanced cation intercalation in energy harvesting Applications: A review

Fuel cells offer the possibility of zero-emissions electricity generation and increased energy security. We review here the current status of solid oxide (SOFC) and polymer electrolyte membrane (PEMFC) fuel cells. Such solid electrolyte systems obviate the need to contain corrosive liquids and are thus preferred by many developers over alkali, phosphoric acid or molten carbonate fuel cells. Dramatic improvements in power densities have been achieved in both SOFC and PEMFC systems through reduction of the electrolyte thickness and architectural control of the composite electrodes. Current efforts are aimed at reducing SOFC costs by lowering operating temperatures to 500–800 °C, and reducing PEMFC system complexity be developing ‘water-free’ membranes which can also be operated at temperatures slightly above 100 °C.

Fuel cell materials and components

Graphene oxide is a rising star among 2D materials, yet its interaction with liquid water remains a fundamentally open question: experimental characterization at the atomic scale is difficult, and modelling by classical approaches cannot properly describe chemical reactivity. Here, we bridge the gap between simple computational models and complex experimental systems, by realistic first-principles molecular simulations of graphene oxide (GO) in liquid water. We construct chemically accurate GO models and study their behavior in water, showing that oxygen-bearing functional groups (hydroxyl and epoxides) are preferentially clustered on the graphene oxide layer. We demonstrated the specific properties of GO in water, an unusual combination of both hydrophilicity and fast water dynamics. Finally, we evidence that GO is chemically active in water, acquiring an average negative charge of the order of 10~mC m$^{-2}$. The ab initio modelling highlights the uniqueness of GO structures for applications as innovative membranes for desalination and water purification.

Structure and Chemistry of Graphene Oxide in Liquid Water from First Principles

https://onlinelibrary.wiley.com/doi/pdf/10.1002/ese3.833

Recent advances in graphene‐based materials for fuel cell applications

Biosensors are analytical devices which find extensive applications in fields such as the food industry, defense sector, environmental monitoring, and in clinical diagnosis. Similarly, intrinsically conducting polymers (ICPs) and their composites have lured immense interest in bio-sensing due to their various attributes like compatibility with biological molecules, efficient electron transfer upon biochemical reactions, loading of bio-reagent, and immobilization of biomolecules. Further, they are proficient in sensing diverse biological species and compounds like glucose (detection limit ≈0.18 nm), DNA (≈10 pm), cholesterol (≈1 µm), aptamer (≈0.8 pm), and also cancer cells (≈5 pm mL-1) making them a potential candidate for biological sensing functions. ICPs and their composites have been extensively exploited by researchers in the field of biosensors owing to these peculiarities; however, no consolidated literature on the usage of conducting polymer composites for biosensing functions is available. This review extensively elucidates on ICP composites and doped conjugated polymers for biosensing functions of copious biological species. In addition, a brief overview is provided on various forms of biosensors, their sensing mechanisms, and various methods of immobilizing biological species along with the life cycle assessment of biosensors for various biosensing applications, and their cost analysis.

Progress in the Development of Intrinsically Conducting Polymer Composites as Biosensors.

The proton exchange membrane fuel cell (PEMFC) converts chemical energy into electrical energy via electrochemical reaction between hydrogen and oxygen, with heat and water as byproducts. When a PEMFC is engineered with polymer electrolyte membrane, e.g., Nafion and polybenzimidazole (PBI), it helps to enhance the performance of the fuel cell under monitored environmental conditions, i.e., high proton conductivity, improved electrode kinetics, and tailoring of properties, along with low tolerance for carbon monoxide. Recently discovered “graphene” has enticed the scientific community, because of its exceptional properties. As per the literature, PEMFCs engineered with graphene can yield high power density, along with 38% enhanced current density, and 257% improved ionic conductivity. In this context, the present review gives the state-of-the-art and progress on polymer electrolyte membranes engineered using graphene and graphene oxide, as well as their synthesis routes and the influence on the performance...

Nikhil Chemmenchery

Papers

Graphene and Graphene Oxide for Fuel Cell Technology