Prospects and Design Insights of Neat Ionic Liquids as Supercapacitor Electrolytes

Ionic liquids present an opportunity to design efficient electrolytes for supercapacitors, which are among the most extensively studied electrochemical energy storage systems. Ionic liquids are promising candidates for supercapacitor electrolytes because they can eliminate issues associated with aqueous and organic solvent-based electrolytes, such as narrow operating potential windows, safety, and performance. The full potential of ionic liquids as electrolytes in supercapacitors need to be further explored due to promising previous efforts invested in ionic liquid-based electrolyte systems for supercapacitor. This review aims to provide an outlook on neat (pure) ionic liquids applied as supercapacitor electrolytes to isolate the prospects and influences of ionic liquids in supercapacitor electrolyte systems. This work primarily focuses on ionic liquid chemistry links to their performance in supercapacitor electrolytes. Deduced features of importance to supercapacitor performance include the presence of functional groups in the ionic liquids, the ionic liquids physicochemical and electrochemical properties. With the different classes of ionic liquids evaluated, ion size-pore size matching of ionic liquid electrolytes and electrode materials, respectively, affect resulting capacitances and energy densities. Several design strategies to enhance supercapacitor performance by improving ionic liquid transport and electrochemical properties are proposed. The proposed strategies and obtained insights consequently informed further discussions on challenges associated with the commercialization of ionic liquids electrolytes.

Application of Ferrites as Electrodes for Supercapacitor

Apart from the magnetic properties, ferrites have been considered as efficient electrodes for next generation energy storage devices. This chapter will include applications of spinel ferrites such as MnFe2O4, CoFe2O4, ZnFe2O4 and NiFe2O4 in supercapacitor. In ferrites, the charge storage arises from the fast-reversible surface redox reactions at the electrode/electrolyte interface. In particular, the electrode material with high specific capacitance, wide range of operating potential, low synthesis cost and its availability on the earth are highly desirable to fabricate a supercapacitor. Ferrites with mixed oxidation states have proved as promising electrodes in supercapacitors. In this chapter, we summarize the different synthesis methods of ferrites based nanocomposites and their electrochemical properties for supercapacitor application.

A meta-review using the ROBIS tool of effective doses in dental and maxillofacial cone beam CT

Objectives: To apply the ROBIS tool for assessment of risk of bias (RoB) in systematic reviews (SRs) in a meta-review on effective doses (EDs) in dental and maxillofacial cone beam CT. Methods: Three electronic databases and reference lists of included SRs were searched. Eligible SRs were classified as having low, high or unclear RoB. Findings of SRs were synthesised and data from primary studies combined to relate ED to field of view (FOV) and operating potential (kV). Results: Seven SRs were included: three displayed low RoB, three high and one had unclear RoB. Only one SR related ED to image quality. Deficiencies in reporting of eligibility criteria, study selection and synthesis of results in SRs were identified. Median ED for three FOV categories differed significantly (p < 0.001) but there was no significant difference in median ED between three operating potential groups. Conclusion: The ROBIS tool should have a role for meta-reviews of different aspects of radiology. The disappointing results for RoB might be remedied by developing standards to improve the quality of reporting of primary dosimetry studies and of SRs. There is a continuing need to perform dosimetry studies, although relating ED to image quality or diagnostic accuracy would add value. Advances in knowledge: This meta-review is the first in radiology to implement ROBIS to assess RoB in SRs of ED and identified that the trustworthiness of some SRs is questionable. The results underpin the importance of FOV dimensions as a determinant of ED in CBCT.

In Situ Fabrication of Activated Carbon from a Bio-Waste Desmostachya bipinnata for the Improved Supercapacitor Performance

Herein, we demonstrate the fabrication of highly capacitive activated carbon (AC) using a bio-waste Kusha grass (Desmostachya bipinnata), by employing a chemical process followed by activation through KOH. The as-synthesized few-layered activated carbon has been confirmed through X-ray powder diffraction, transmission electron microscopy, and Raman spectroscopy techniques. The chemical environment of the as-prepared sample has been accessed through FTIR and UV–visible spectroscopy. The surface area and porosity of the as-synthesized material have been accessed through the Brunauer–Emmett–Teller method. All the electrochemical measurements have been performed through cyclic voltammetry and galvanometric charging/discharging (GCD) method, but primarily, we focus on GCD due to the accuracy of the technique. Moreover, the as-synthesized AC material shows a maximum specific capacitance as 218 F g−1 in the potential window ranging from − 0.35 to + 0.45 V. Also, the AC exhibits an excellent energy density of ~ 19.3 Wh kg−1 and power density of ~ 277.92 W kg−1, respectively, in the same operating potential window. It has also shown very good capacitance retention capability even after 5000th cycles. The fabricated supercapacitor shows a good energy density and power density, respectively, and good retention in capacitance at remarkably higher charging/discharging rates with excellent cycling stability. Henceforth, bio-waste Kusha grass-derived activated carbon (DP-AC) shows good promise and can be applied in supercapacitor applications due to its outstanding electrochemical properties. Herein, we envision that our results illustrate a simple and innovative approach to synthesize a bio-waste Kusha grass-derived activated carbon (DP-AC) as an emerging supercapacitor electrode material and widen its practical application in electrochemical energy storage fields.

Electrochemical Double-Layer Capacitor Containing Mixtures of Ionic Liquid, Lithium Salt, and Organic Solvent as an Electrolyte

A modified ionic liquid (IL)-based electrolyte, with conventional carbonates as the support solvent and lithium salt as the additive, was designed for a high-voltage electrochemical double-layer capacitor (EDLC). It is found that the employment of carbonate solvents enhances the ionic conductivity and decreases the viscosity of the electrolyte. At the same time, the addition of lithium salt plays a key role in the stabilization of the operating potential window and the modification of the passivation layer on the electrode. As a result, increased specific capacitance, improved cycle stability, and rate capability are demonstrated in the EDLC with an EMI-BF4/LiPF6/PC/DMC electrolyte at the upper voltage of 3 V, in contrast to that with pure IL and IL/carbonate mixture. This study primarily stresses the combination effect of Li salt and organic solvent in an IL electrolyte system for constructing advanced 3 V-class EDLC with excellent overall performance.

Coulomb Blockade Effects by Single Electron Tunneling Methods in Cylindrical Dual Gate OLET Configuration

In the field of nano electronics some nano-structure applications such as quantum dots (QDs), wires, wells and bulks must have distinctive potentials. These crystal structures emerged by an inorganic organic hybrid halide materials which processes in tremendous optoelectronic applications like electroluminescence, photoluminescence quantum yield (93.2%). There is a need of coupling to their surroundings by these structures which can either add or subtract electrons from the electrodes. As per state of the art the significant research efforts in about an isolated quantum dot coupling through tunneling of two leads that is source lead for supply of electrons and a drain lead for removes of electrons and their performances will be offered and discussed in the view for the realization of possible between Dual Gate Cylindrical Organic Light Emitting Transistor (OLET) architectures. In this article we examined the optical as well as electrical characteristics operation of cylindrical Dual Gate OLET (CDGOLET). Last year perovskite quantum dot (PQD) most preferred for the purpose of light-emitting transistors with high brightness of up to 1.432× 104 cd m− 2, high electron mobility’s of up to 14.052 cm2 v− 1 s− 1, and their external quantum efficiencies (EQE) of up to 1.85% operating at a source drain operating potential of 50 V.

Supercapacitor electrode materials: addressing challenges in mechanism and charge storage

In recent years, rapid technological advances have required the development of energy-related devices. In this regard, Supercapacitors (SCs) have been reported to be one of the most potential candidates to meet the demands of human’s sustainable development owing to their unique properties such as outstanding cycling life, safe operation, low processing cost, and high power density compared to the batteries. This review describes the concise aspects of SCs including charge-storage mechanisms and scientific principles design of SCs as well as energy-related performance. In addition, the most important performance parameters of SCs, such as the operating potential window, electrolyte, and full cell voltage, are reviewed. Researches on electrode materials are crucial to SCs because they play a pivotal role in the performance of SCs. This review outlines recent research progress of carbon-based materials, transition metal oxides, sulfides, hydroxides, MXenes, and metal nitrides. Finally, we give a brief outline of SCs’ strategic direction for future growth.