Jang-soo Lee

• PostDoc Position at Stanford University

Owing to its high potential, Zn–air battery with a century old technology has been drawing attention recently. However, it is still under research and development stage so that its maximum application has been significantly limited to small portable devices such as just hearing aids. In this article, we briefly introduce possible degradation mechan...

The electrochemical performance of perovskite complex was found out to depend greatly on the different locations of the identical particle, which represent different surface charges accordingly. The surface charges were evaluated by Zeta potential (ζ) for the intrinsic BSCF5582 (Ba0.5Sr0.5Co0.8Fe0.2O3−δ: BSCF5582), ball-milled (BM-BSCF5582) and hea...

In article number 1601052, Yi Cui, Jaephil Cho, and co-workers report a facile and scalable strategy for synthesizing electrocatalysts for metal-air batteries. The obtained catalysts exhibit better performances in a Zn-air single cell at high current densities than a Pt/C electrode. The cover image shows the composites of the N-doped carbon sheets...

To date, most studies have focused only on the interaction between oxygen and the catalyst, with the intention of minimizing the mass-transfer resistance by using the rotating disk electrode (RDE) method, which is based on the forced-convection theory. To begin with, in order to increase the reaction rate, the oxygen should be able to reach the act...

Chemically prepared λ-MnO2 has not been intensively studied as a material for metal-air batteries, fuel cells, or supercapacitors because of their relatively poor electrochemical properties compared to α- and δ-MnO2 . Herein, through the electrochemical removal of lithium from LiMn2 O4 , highly crystalline λ-MnO2 was prepared as an efficient electr...

Chemically prepared λ-MnO2 has not been intensively studied as a material for metal–air batteries, fuel cells, or supercapacitors because of their relatively poor electrochemical properties compared to α- and δ-MnO2. Herein, through the electrochemical removal of lithium from LiMn2O4, highly crystalline λ-MnO2 was prepared as an efficient electroca...

Understanding the interaction between a catalyst and oxygen has been a key step in designing better electrocatalysts for the oxygen reduction reaction (ORR), as well as applying them in metal-air batteries and fuel cells. Alloying has been studied to finely tune the catalyst electronic structures, so as to afford proper binding affinities for oxyge...

A cable-type flexible Zn-air battery with a spiral zinc anode, gel polymer electrolyte (GPE), and air cathode coated on a nonprecious metal catalyst is designed in order to extend its application area toward wearable electronic devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

La0.3(Ba0.5Sr0.5)0.7Co 0.8Fe0.2O3-δ is a promising bifunctional perovskite catalyst for the oxygen reduction reaction and the oxygen evolution reaction. This catalyst has circa 10 nm-scale rhombohedral LaCoO3 cobaltite particles distributed on the surface. The dynamic microstructure phenomena are attributed to the charge imbalance from the replacem...

Electrocatalysts facilitating oxygen reduction reaction (ORR) are vital components in advanced fuel cells and metal-air batteries. Here we report ketjenblack incorporated nitrogen-doped carbon sheets derived from gelatine and apply these easily scalable materials as metal-free electrocatalysts for ORR. These carbon nanosheets demonstrate highly com...

Highly porous nitrogen doped carbon fibers like churros morphology are prepared from a simple and cost-effective fabrication process, electrospinning with bicomponent polymer consisting of polystyrene (PS) and polyacrylonitrile (PAN). From appropriate ratio of two polymer and pyrolysis at 1100oC, newly churros morphology with extremely high surface...

We report metal-free electrocatalysts to enhance utilization of dissolved and gaseous oxygen during oxygen reduction reaction (ORR). Proper balance between hydrophobicity and hydrophilicity is achieved using reduced graphene oxide (rGO) and polyelectrolyte functionalized multiwalled carbon nanotubes (pMWNTs). In this unique architecture, both two-...

Inspired by the tetrapod structures of a breakwater, a highly efficient electrocatalyst for oxygen reduction reaction (ORR) in alkaline solution has been created from low-cost, commercial melamine foam and ketjenblack. The unique porous architecture greatly facilitates rapid mass transport, while the N-doped ketjenblack and Fe/Fe(3) C-functionalize...

Non-precious catalysts for oxygen reduction reactions in the air electrode play a vital role in reducing polarization during cycling and therefore enhancing the performance of metal-air batteries which, among electrochemical energy-storage devices, have the potential to offer the highest energy density, representing the most promising systems for p...

A composite air electrode consisting of Ketjenblack carbon (KB) supported amorphous manganese oxide (MnOx) nanowires, synthesized via a polyol method, is highly efficient for the oxygen reduction reaction (ORR) in a Zn-air battery. The low-cost and highly conductive KB in this composite electrode overcomes the limitations due to low electrical cond...

Ionic liquid (IL) modified reduced graphene oxide (rGO-IL) nanosheets anchoring manganese oxide (Mn3O4) are synthesized via a facile solution-based growth mechanism and applied to a Zn-air battery as an effective electrocatalyst for the oxygen reduction reaction (ORR). In this study, the IL moiety in these composites increases not only the conducti...

In the past decade, there have been exciting developments in the field of lithium ion batteries as energy storage devices, resulting in the application of lithium ion batteries in areas ranging from small portable electric devices to large power systems such as hybrid electric vehicles. However, the maximum energy density of current lithium ion bat...

Optical activity is the result of chiral molecules interacting differently with left versus right circularly polarized light. Because of this intrinsic link to molecular structure, the determination of optical activity through circular dichroism (CD) spectroscopy has long served as a routine method for obtaining structural information about chemica...

Alanine dipeptide analog 1 backbone-caged with a photolabile linker, 4,5-dimethoxy-2-nitrobenzyl (DmNb), was synthesized. UV-pulse-induced photochemical reaction of 1 was monitored by Fourier transform IR absorption spectroscopy under a steady-state condition or in a fast-scan mode. Upon photolysis of 1, the amide I band is changed from a doublet t...