The performance of electrochemical devices using ionic liquids (ILs) as electrolytes can be impaired by water uptake. This work investigates the influence of water on the behavior of hydrophilic and hydrophobic ILswith ethylsulfate and tris(perfluoroalkyl)trifluorophosphate or bis(trifluoromethyl sulfonyl)imide (TFSI) anions, respectivelyon electrified graphene, a promising electrode material. The results show that water uptake slightly reduces the IL electrochemical stability and significantly influences graphene’s potential of zero charge, which is justified by the extent of anion depletion from the surface. Experiments confirm the dominant contribution of graphene’s quantum capacitance (C Q ) to the total interfacial capacitance (C int ) near the PZC, as expected from theory. Combining theory and experiments reveals that the hydrophilic IL efficiently screens surface charge and exhibits the largest double layer capacitance (C IL ∼ 80 μF cm–2), so that C Q governs the charge stored. The hydrophobic ILs are less efficient in charge screening and thus exhibit a smaller capacitance (C IL ∼ 6–9 μF cm–2), which governs C int already at small potentials. An increase in the total interfacial capacitance is observed at positive voltages for humid TFSI-ILs relative to dry ones, consistent with the presence of a satellite peak. Short-range surface forces reveal the change of the interfacial layering with potential and water uptake owing to reorientation of counterions, counterion binding, co-ion repulsion, and water enrichment. These results are consistent with the charge being mainly stored in a ∼2 nm-thick double layer, which implies that ILs behave as highly concentrated electrolytes. This knowledge will advance the design of IL-graphene-based electrochemical devices.

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Research and development with regards to battery technologies have been evolving at a profitably good rate with an impressive amount of progress being made at different levels. Graphite has been continuously preferred as the anode material for lithium-ion batteries since its commercialization in 1991. The interlayer spacing of about 3.35 Å promotes the intercalation of guest ions, thereby resulting in what is called graphite intercalation compounds (GICs). Through such intercalation mechanisms, graphite can contribute to electrochemical charge transfer owing to its ionic and electronic conduction properties. The intercalation of alkali metal ions into graphite is considered the epitome of ion intercalation with regards to layered materials. Putting together various inferences made through the years, this review aims at establishing a foundational understanding of GICs and their applications in energy storage devices. A brief overview of graphite intercalation chemistry has been provided and discussions on the advancements in various GICs ranging from binary-GICs to ternary-GICs have been elaborated. Towards the end, this paper provides a comprehension of the specific strategies that might improve the performance of a GIC, following which the challenges and the future of GIC-based research have also been highlighted.

Identification of defense-related genes in the host is one of the most essential steps in understanding disease resistance mechanisms in plants. In this study, a suppression subtractive hybridization (SSH) library was constructed to study differential gene expression in banana plants mediated through a Fusarium wilt pathogen (Fusarium oxysporum f.sp cubense-Foc) and its interaction with the Foc effective biocontrol agent Trichoderma asperellum (prr2). Here cDNAs from the roots of banana cv. Grand Naine infected by Foc were used as the driver and cDNAs from Foc + T. asperellum inoculated banana plants as the tester population. After hybridization and cloning, an EST library of 300 nonredundant clones was obtained. Based on sequence analysis and a homology search in the NCBI database, the clones were assigned to different functional categories. The expression patterns of six selected defense-related genes, namely endochitinase, polyubiquitin, calmodulin binding protein, pleotropic drug resistant gene, isoflavone reductase, and mannose binding lectin, were analyzed through quantitative real-time PCR in Foc alone inoculated and Foc + T. asperellum inoculated banana plants. It was observed that the expression of these genes during initial progression of disease was higher in Foc + T. asperellum inoculated plants as compared to Foc alone inoculated plants. Our results constitute a step toward a better understanding of the role of mycoparasitic T. asperellum in plant defense during its interaction with Foc in the susceptible banana cultivar Grand Naine.

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