임종우 교수

Recent years have witnessed an upsurge in the development of non-precious catalysts (NPCs) for alkaline water electrolysis (AWE), especially with the strides made in experimental and computational techniques. In this contribution, the most recent advances in NPCs for AWE were systematically reviewed, emphasizing the application of in situ/operando experimental methods and density functional theory (DFT) calculations in their understanding and development. First, we briefly introduced the fundame

The kinetics and uniformity of ion insertion reactions at the solid-liquid interface govern the rate capability and lifetime, respectively, of electrochemical devices such as Li-ion batteries. Using an operando x-ray microscopy platform that maps the dynamics of the Li composition and insertion rate in Li(x)FePO4, we found that nanoscale spatial variations in rate and in composition control the lithiation pathway at the subparticle length scale. Specifically, spatial variations in the insertion

Although it has been qualitatively demonstrated that surface roughness can reduce the thermal conductivity of crystalline Si nanowires (SiNWs), the underlying reasons remain unknown and warrant quantitative studies and analysis. In this work, vapor-liquid-solid (VLS) grown SiNWs were controllably roughened and then thoroughly characterized with transmission electron microscopy to obtain detailed surface profiles. Once the roughness information (root-mean-square, σ, correlation length, L, and pow

The rampant generation of lithium hydroxide and carbonate impurities, commonly known as residual lithium, is a practical obstacle to the mass-scale synthesis and handling of high-nickel (>90 %) layered oxides and their use as high-energy-density cathodes for lithium-ion batteries. Herein, we suggest a simple in situ method to control the residual lithium chemistry of a high-nickel lithium layered oxide, Li(Ni_0.91 Co_0.06 Mn_0.03 )O₂ (NCM9163), with minim

The growth of dendrites on lithium metal electrodes is problematic because it causes irreversible capacity loss and safety hazards. Localised high-concentration electrolytes (LHCEs) can form a mechanically stable solid-electrolyte interphase and prevent uneven growth of lithium metal. However, the optimal physicochemical properties of LHCEs have not been clearly determined which limits the choice to fluorinated non-solvating cosolvents (FNSCs). Also, FNSCs in LHCEs raise environmental concerns,

Block copolymer patterned holey silicon (HS) was successfully integrated into a microdevice for simultaneous measurements of Seebeck coefficient, electrical conductivity, and thermal conductivity of the same HS microribbon. These fully integrated HS microdevices provided excellent platforms for the systematic investigation of thermoelectric transport properties tailored by the dimensions of the periodic hole array, that is, neck and pitch size, and the doping concentrations. Specifically, thermo

Abstract The development of sustainable energy conversion and storage devices, such as fuel cells, metal–air batteries, and electrolyzers is highly dependent on the catalytic oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), and carbon dioxide reduction reaction (CO 2 RR). Carbon‐supported nonprecious metals (C@NPMs) with variable metal sizes (single atom, cluster, and nanoparticle) are attracting significant interest for catalyzing these reacti

During solid-state calcination, with increasing temperature, materials undergo complex phase transitions with heterogeneous solid-state reactions and mass transport. Precise control of the calcination chemistry is therefore crucial for synthesizing state-of-the-art Ni-rich layered oxides (LiNi_1-x-y Co_x Mn_y O₂ , NRNCM) as cathode materials for lithium-ion batteries. Although the battery performance depends on the chemical heterogeneity during NRNCM calc

Systematic control of surface reconstruction during catalysis remains challenging. Particularly, inducing a surface structure reconstruction following the lattice oxygen oxidation mechanism (LOM), which can reduce the overpotential in oxygen evolution reaction (OER) catalysts, has not been extensively investigated. The mechanism of the OER of transition-metal-oxide-based catalysts can be facilitated by manipulating the local coordination structure to modulate the reactivity of lattice oxygen. He

The era of miniaturized and customized electronics requires scalable energy storage devices with versatile shapes. From the perspective of manufacturing, direct ink writing (DIW)-based 3D printing has attracted unprecedented interest, paving the way to demonstrate micro-batteries with design freedom and outstanding performance. Despite demands for all-printed Li-ion batteries with maskless processing, most of the efforts have been dedicated to developing printable active electrodes or building t

Silicon is an attractive anode material for all-solid-state batteries (ASSBs) because it has a high energy density and is safer than metallic lithium. Conventional silicon powder composite electrodes have significant internal voids and detrimental interfaces that suppress the lithium transport and lifetime. Here, we demonstrate that surface-treated thin silicon wafers could serve as monolithic additive-free, electrolyte-free, and void-free electrodes that can achieve high areal capacity at room

Understanding the cycling rate-dependent kinetics is crucial for managing the performance of batteries in high-power applications. Although high cycling rates may induce reaction heterogeneity and affect battery lifetime and capacity utilization, such phase transformation dynamics are poorly understood and uncontrollable. In this study, synchrotron-based operando X-ray diffraction is performed to monitor the high-current-induced phase transformation kinetics of LiNi_0.6 Co<sub>0.2</sub

Abstract The electrochemical reduction of carbon dioxide offers a sound and economically viable technology for the electrification and decarbonization of the chemical and fuel industries. In this technology, an electrocatalytic material and renewable energy‐generated electricity drive the conversion of carbon dioxide into high‐value chemicals and carbon‐neutral fuels. Over the past few years, single‐atom catalysts have been intensively studied as they could provide near‐unity atom utilization an