이현욱 교수

Ultrathin LiMn(2)O(4) nanowires with cubic spinel structure were synthesized by using a solvothermal reaction to produce α-MnO(2) nanowire followed by solid-state lithiation. LiMn(2)O(4) nanowires have diameters less than 10 nm and lengths of several micrometers. Galvanostatic battery testing showed that LiMn(2)O(4) nanowires deliver 100 and 78 mAh/g at very high rate (60C and 150C, respectively) in a larger potential window with very good capacity retention and outstanding structural stability.

Abstract The propensity of lithium dendrite formation during the charging process of lithium metal batteries is linked to inhomogeneity on the lithium surface layer. The high reactivity of lithium and the complex surface structure of the native layer create “hot spots” for fast dendritic growth. Here, it is demonstrated that a fundamental restructuring of the lithium surface in the form of lithium silicide (Li x Si) can effectively eliminate the surface inhomogeneity on the lithium surface. In s

Abstract A significant volume expansion exhibited by high‐capacity active materials upon lithiation has hindered their application as Li‐ion battery anode materials. Although tremendous progress has been made in the development of coating methods that improve the stability of high‐capacity active materials, suitable coating sources that are both strong and economical to use are yet to be discovered. Pitch is reported here as a promising coating source for high‐capacity anodes owing to the high m

Sodium (Na) metal anodes with stable electrochemical cycling have attracted widespread attention because of their highest specific capacity and lowest potential among anode materials for Na batteries. The main challenges associated with Na metal anodes are dendritic formation and the low density of deposited Na during electrochemical plating. Here, we demonstrate a fluoroethylene carbonate (FEC)-based electrolyte with 1 M sodium bis(fluorosulfonyl)imide (NaFSI) salt for the stable and dense depo

Metallic lithium (Li) and sodium (Na) anodes have received great attention as ideal anodes to meet the needs for high energy density batteries due to their highest theoretical capacities. Although many approaches have successfully improved the performances of Li or Na metal anodes, many of these methods are difficult to scale up and thus cannot be applied in the production of batteries in practice. In this work, we introduce nanocrevasses in a carbon fiber scaffold which can facilitate the penet

Although solid-state batteries with lithium metal could enable higher energy density and better safety characteristics than Li-ion batteries, the complex electro-chemo-mechanical evolution of the Li–solid-state electrolyte interface can diminish performance. Here, we measure the stack pressure in real time to provide new insights into the effects of applied stack pressure and electrolyte processing on the interfacial behavior of two representative solid-state electrolytes, Li10SnP2S12 and Li6PS5

Nanostructural design renders several breakthroughs for the construction of high-performance materials and devices including energy-storage systems. Although attempts made toward electrode engineering have improved the existing drawbacks, nanoengineering is still hindered by some issues. To achieve practical applications of lithium–sulfur (Li–S) batteries, it is difficult to attain a high areal capacity with stable cycling. Physical encapsulation via nanostructural design not only can resolve th

Sulfur is an attractive cathode material for next-generation lithium batteries due to its high theoretical capacity and low cost. However, dissolution of its lithiated product (lithium polysulfides) into the electrolyte limits the practical application of lithium sulfur batteries. Here we demonstrate that sulfur particles can be hermetically encapsulated by leveraging on the unique properties of two-dimensional materials such as molybdenum disulfide (MoS 2 ). The high flexibility and strong van

This work presents that Cu with atomic-scale spacings ( d s ) efficiently catalyses the electrochemical co-reduction of CO 2 and NO 3 − to urea. Specifically, Cu with d s near 6 Å (6 Å-Cu) produces urea with a high yield rate and partial current density.

A facile synthetic strategy was implemented to obtain nanosized barium titanate ( BaTiO 3 ) powders with tetragonal structure. The nanoparticles were synthesized using solvothermal process employing diethanolamine and triethanolamine to suppress the particle growth and the as‐prepared nanopowders were characterized using X‐ray diffraction, scanning electron microscopy, and high‐resolution dispersive R aman spectroscopy. It was found that the particle size can be easily tuned by adjusting the exp

Abstract The inability to guide the nucleation locations of electrochemically deposited Li has long been considered the main factor limiting the utilization of high‐energy‐density Li‐metal batteries. In this study, an electrical conductivity gradient interfacial host comprising 1D high conductivity copper nanowires and nanocellulose insulating layers is used in stable Li‐metal anodes. The conductivity gradient system guides the nucleation sites of Li‐metal to be directed during electrochemical p

Nitrogen (N) and sulfur (S) co-doped porous carbon materials (NSPCs) have been prepared by the two-dimensional interlayer confinement effect of a layered double hydroxide (LDH).

High Resolution Image Download MS PowerPoint Slide It is crucial to comprehend the effect of the solid electrolyte interphase (SEI) on battery performance to develop stable Li metal batteries. Nonetheless, the exact nanostructure and working mechanisms of the SEI remain obscure. Here, we have investigated the relationship between electrolyte components and the structural configuration of interfacial layers using an optimized cryogenic transmission electron microscopy (Cryo-TEM) analysis and theo