김웅 교수

All-solid-state flexible supercapacitors were fabricated using carbon nanotubes (CNTs), regular office papers, and ionic-liquid-based gel electrolytes. Flexible electrodes were made by coating CNTs on office papers by a drop-dry method. The gel electrolyte was prepared by mixing fumed silica nanopowders with ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf(2)]). This supercapacitor showed high power and energy performance as a solid-state flexible supercapa

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ~75 F g(-1), ~987 kW kg(-1) and ~27 W h kg(-1), respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidati

We demonstrate 2.5 V AC-line-filtering supercapacitors with unprecedentedly high volumetric energy density based on ultrathin carbon nanotube films.

CMK-3/CNT supercapacitors exhibit sufficiently fast response speed and high areal capacitance for AC line filtering.

Water-in-salt electrolytes (WiSEs) are a promising candidate for use in energy storage devices because of their wide electrochemical stability window (ESW) that overcomes the thermodynamic limit of water electrolysis (1.23 V). Despite the high energy density arising from the wide ESW, it is assumed that the power density of WiSE-based energy storage devices will always be less than those that operate with dilute electrolytes because of the higher viscosity of WiSEs. However, the present study de

In view of the need for environmental friendliness and cost effectiveness, the enhancement of the energy density of the aqueous supercapacitor is in high demand. Recently, concentrated aqueous electrolytes known as water-in-salt electrolytes (WiSEs) have attracted much attention due to their broad electrochemical stability window (2–3 V) relative to that of conventional dilute aqueous electrolytes (∼1 V). Meanwhile, the development of redox-active electrolytes has provided a great opportunity to

Abstract Supercapacitors (SCs) are considered to be a promising energy storage device owing to their high‐power characteristics and long‐term cycling stabilities. Recently, ultrafast SCs have been extensively studied in the context of replacing the aluminum electrolytic capacitors (AECs) that are currently used for alternating current (AC) line filtering applications. Since the ultrafast SCs are generally more compact owing to their higher energy density, as compared to the AECs, replacement of

Mass spectrometry is the enabling technology for proteomics. To fully realize the enormous potential of lab-on-a-chip in proteomics, a major advance in interfacing microfluidics with mass spectrometry is needed. Here, we report the first demonstration of monolithic integration of multinozzle electrospray emitters with a microfluidic channel via a novel silicon microfabrication process. These microfabricated monolithic multinozzle emitters (M3 emitters) can be readily mass-produced from silicon w

A redox-active electrolyte supercapacitor (RAES) is a promising system that increases the energy density of a supercapacitor by providing additional pseudocapacitance, which arises from an inserted redox couple in an electrolyte. However, the energy density of RAESs is still considerably low for practical applications, and enhancing the operating voltage window as well as the capacitance of RAESs is very necessary. In this study, we rationally designed a nonaqueous redox-active electrolyte mainl

The development of synthetic methods for monodisperse nanomaterial is of great importance in science and technology related to nanomaterials. The strong demands to prepare exceptionally monodisperse nanocrystals have made digestive-ripening one of the most sought-after size-focusing processes. Although digestive-ripening processes have been demonstrated to produce various metals and semiconductors, their applicability to oxides has rarely been studied despite various unique properties and applic

Among the various upconversion (UC) materials, sodium yttrium fluoride doped with ytterbium and erbium (NaYF₄:Yb³⁺,Er³⁺) is the most widely studied owing to its high UC efficiency. Nonetheless, UC mechanisms are not yet fully understood and, in particular, near-infrared-to-red UC mechanisms are still under debate. Herein, we examine UC mechanisms in Er³⁺-based UC materials. Most importantly, the ⁴F_3/2 and ⁴F<sub>5/2</su