Since the ability of ionic liquid (IL) was demonstrated to act as a solvent or an electrolyte, IL-based electrolytes have been widely used as a potential candidate for renewable energy storage devices, like lithium ion batteries (LIBs) and supercapacitors (SCs). In this review, we aimed to present the state-of-the-art of IL-based electrolytes electrochemical, cycling, and physicochemical properties, which are crucial for LIBs and SCs. ILs can also be regarded as designer solvents to replace the more flammable organic carbonates and improve the green credentials and performance of energy storage devices, especially LIBs and SCs. This review affords an outline of the progress of ILs in energy-related applications and provides essential ideas on the emerging challenges and openings that may motivate the scientific communities to move towards IL-based energy devices. Finally, the challenges in design of the new type of ILs structures for energy and environmental applications are also highlighted.

Transition metal oxides used as electrode materials for flexible supercapacitors have attracted huge attention due to their high specific capacitance and surface-to-volume ratio, specifically for cobalt oxide (Co₃O₄) nanoparticles.

We report a simple and mass-scalable approach for thin MoS₂ films via RF sputtering combined with the post-deposition annealing process. We have prepared as-sputtered film using a MoS₂ target in the sputtering system. The as-sputtered film was subjected to post-deposition annealing to improve crystalline quality at 700 °C in a sulfur and argon environment. The analysis confirmed the growth of continuous bilayer to few-layer MoS₂ film. The mobility value of ~29 cm²/Vs and current on/off ratio on the order of ~10⁴ were obtained for bilayer MoS₂. The mobility increased up to ~173–181 cm²/Vs, respectively, for few-layer MoS₂. The mobility of our bilayer MoS₂ FETs is larger than any previously reported values of single to bilayer MoS₂ grown on SiO₂/Si substrate with a SiO₂ gate oxide. Moreover, our few-layer MoS₂ FETs exhibited the highest mobility value ever reported for any MoS₂ FETs with a SiO₂ gate oxide. It is presumed that the high mobility behavior of our film could be attributed to low charged impurities of our film and dielectric screening effect by an interfacial MoO_xSi_y layer. The combined preparation route of RF sputtering and post-deposition annealing process opens up the novel possibility of mass and batch production of MoS₂ film.