서동화 교수

Abstract Designing highly conductive and (electro)chemical stable inorganic solid electrolytes using cost-effective materials is crucial for developing all-solid-state batteries. Here, we report halide nanocomposite solid electrolytes (HNSEs) ZrO 2 (-ACl)-A 2 ZrCl 6 (A = Li or Na) that demonstrate improved ionic conductivities at 30 °C, from 0.40 to 1.3 mS cm −1 and from 0.011 to 0.11 mS cm −1 for Li + and Na + , respectively, compared to A 2 ZrCl 6 , and improved compatibility with sulfide soli

Transition-metal (TM) oxides play an increasingly important role in technology today, including applications such as catalysis, solar energy harvesting, and energy storage. In many of these applications, the details of their electronic structure near the Fermi level are critically important for their properties. We propose a first-principles--based computational methodology for the accurate prediction of oxygen charge transfer in TM oxides and lithium TM (Li-TM) oxides. To obtain accurate electr

The in-depth study of the multicomponent effect on the structural and electrochemical properties of olivine cathodes is conducted using state-of-the-art first-principles calculations. The distribution of multiple transition metals in olivine structure alters local crystal structure and electronic structure, affecting its kinetic and thermodynamic properties. We find that local structure change, such as the reduced Jahn−Teller effect of Mn, significantly enhances both Li mobility and electron (po

Abstract Anode‐free Li metal batteries are one of the finest prospects for increasing energy density beyond that of standard lithium‐ion batteries. Conversely, the absence of Li reservoir generates unwarranted volume expansion, permitting electrolyte depletion and rapid cathode capacity consumption. To address this issue, an anode‐free Li metal battery with an ion‐conductive layer coated Cu current collector Ag/L in typical carbonate‐based electrolytes is presented. The ion‐conducting layer caus

A computational study of the electrochemical properties of three isotopic LiMBO${}_{3}$ compounds (M $=$ Mn, Fe, and Co) as cathode materials is conducted using state-of-the-art first-principles calculations. The calculation of the Li intercalation potentials of LiMBO${}_{3}$ predicts that the theoretical energy density (660--860 Wh kg${}^{\ensuremath{-}1}$) can be comparable to or even higher than the corresponding olivine phosphates (595 Wh kg${}^{\ensuremath{-}1}$ for LiFePO${}_{4}$). In addi

Abstract The development of Li‐excess disordered‐rocksalt (DRX) cathodes for Li‐ion batteries and interpretation through the framework of percolation theory of Li diffusion have steered researchers to consider “Li‐excess” ( x > 1.1 in Li x TM 2− x O 2 ; TM = transition metal) as being critical to achieving high performance. It is shown that this is not necessary for Mn‐rich DRX‐cathodes demonstrated by Li 1.05 Mn 0.90 Nb 0.05 O 2 and Li 1.20 Mn 0.60 Nb 0.20 O 2 , which both deliver high capac

Abstract In recent years, Li‐ and Mn‐rich layered oxides (LMRs) have been vigorously explored as promising cathodes for next‐generation, Li‐ion batteries due to their high specific energy. Nevertheless, their actual implementation is still far from a reality since the trade‐off relationship between the particle size and chemical reversibility prevents LMRs from achieving a satisfactory, industrial energy density. To solve this material dilemma, herein, a novel morphological and structural design

Abstract Despite intensive studies over decades, the development of electrocatalysts for acidic water splitting still relies on platinum group metals, especially Pt and Ir, which are scarce, expensive, and poorly sustainable. Because such problems can be alleviated, Ru‐based bifunctional catalysts such as rutile RuO 2 have recently emerged. However, RuO 2 has a relatively low activity for hydrogen evolution reactions (HER) and low stability for oxygen evolution reactions (OER) under acidic condi

Abstract Mixed ionic–electronic conductors (MIECs) can play a pivotal role in achieving high energies and power densities in rechargeable batteries owing to their ability to simultaneously conduct ions and electrons. Herein, a new strategy is proposed wherein late 3d transition metals (TMs) are substituted into a perovskite Li‐ion conductor to transform it into a Li‐containing MIEC. First‐principles calculations show that perovskite Li x La y MO 3 with late 3d TMs have a low oxygen vacancy forma

Concurrent modification of linear carbonates combining alkyl-chain extension and alkoxy substitution enables thermally stable high-performance batteries by decreasing volatility and increasing solvation ability simultaneously.

Abstract Aqueous redox flow batteries (RFBs) have attracted significant attention as energy storage systems by virtue of their inexpensive nature and long‐lasting features. Although all‐vanadium RFBs exhibit long lifetimes, the cost of vanadium resources fluctuates considerably, and is generally expensive. Iron–chromium RFBs take advantage of utilizing a low‐cost and large abundance of iron and chromite ore; however, the redox chemistry of Cr II/III generally involves strong Jahn–Teller effects.

Abstract Understanding the local cation order in the crystal structure and its correlation with electrochemical performances has advanced the development of high‐energy Mn‐rich cathode materials for Li‐ion batteries, notably Li‐ and Mn‐rich layered cathodes (LMR, e.g., Li 1.2 Ni 0.13 Mn 0.54 Co 0.13 O 2 ) that are considered as nanocomposite layered materials with C2/m Li 2 MnO 3 ‐type medium‐range order (MRO). Moreover, the Li‐transport rate in high‐capacity Mn‐based disordered rock‐salt (DRX)

In this communication, we use first-principles based multi-level computational methods to predict the crystal structure of Li4C6O6, the key intermediate material that can be oxidized to Li2C6O6 or reduced to Li6C6O6. This predicted structure leads to an X-ray diffraction (XRD) pattern in good agreement with experiment, validating the predicted structure. With this structure in hand one can proceed to determine details for the electrochemical properties of these organic electrodes (chemical poten