강병우 교수

All-Solid-State Batteries (ASSBs) that use oxide-based solid electrolytes (SEs) have been considered as a promising energy-storage platform to meet an increasing demand for Li-ion batteries (LIBs) with improved energy density and superior safety. However, high interfacial resistance between particles in the composite electrode and between electrodes and the use of Li metal in the ASBS hinder their practical utilization. Here, we review recent research progress on oxide-based SEs for the ASSBs wi

LiMnPO 4 was synthesized from an off-stoichiometric mix of starting materials with nominal composition LiMn 0.9 P 0.95 O 4- . Stoichiometric LiMnPO 4 with particle size 50 nm was found with X-ray diffraction even with the large overall deviation from stoichiometry in the sample, indicating that other noncrystalline compounds are present. The off-stoichiometric sample had a discharge capacity of 145 mAh/g at C/10 and 100 mAh/g at 2C after a constant current constant voltage charge. Capacity reten

We tried to understand the reversible capacity of SiO during the first cycle and its effect on the poor initial Coulombic efficiency (ICE). Several SiO samples that have slightly different microstructures were prepared by a solid-state reaction. They have similar irreversible capacities but have different reversible capacities during the first cycle. As a result, the ICEs of the samples increase as their reversible capacities increase. The limited reversible capacity in SiO originates from the d

Co-free Mn-based Li-rich layered materials have been attracting a lot of attention due to their high capacity via the additional oxygen redox reaction and their low cost. However, their poor capacity retention and voltage fade upon cycling remains a problem for practical applications. Herein, we report on long-term cyclability of a Co-free Mn-based Li-rich layered material with superior voltage retention for 490 cycles. The developed one-step solid-state reaction, which comprises a thorough mixi

In this study, electrochemical behaviors of Li2S such as a large potential barrier at the beginning of the 1st charging process and a continuous increase in potential to ∼4 V during the rest of this process were understood through X-ray photoelectron spectroscopy measurements and electrochemical evaluations for a full utilization of Li2S. The large potential barrier to the 1st charge in Li2S can be caused by the presence of insulating oxidized products (Li2SO3 or Li2SO4-like structures) on the s

We report a new triplite-type iron fluoro-sulfate compound, a cation-disordered NaFeSO4F that has redox potential of ∼3.7 V versus Na+/Na0 and can have 138 mA·h/g of theoretical capacity. This compound shows practical energy density (∼430 W·h/kg) comparable to that of several Li-ion battery positive electrode materials such as LiMn2O4 (430 W·h/kg). Therefore, triplite NaFeSO4F is a candidate positive electrode material which can meet the requirements for high energy density Na-ion batteries. Fur

A LISICON-type oxide solid electrolyte has superior chemical/electrochemical compatibilities with high capacity Ni-rich layered oxides and Li metal. LISICON based solid-state battery via co-sintering process operates well at room temperature.

Abstract The quest for high energy density and high power density electrode materials for lithium‐ion batteries has been intensified to meet strongly growing demand for powering electric vehicles. Conventional layered oxides such as Co‐rich LiCoO 2 and Ni‐rich Li(Ni x Mn y Co z )O 2 that rely on only transition metal redox reaction have been faced with growing constraints due to soaring price on cobalt. Therefore, Mn‐rich electrode materials excluding cobalt would be desirable with respect to av

To meet the growing demand for global electrical energy storage, high-energy-density electrode materials are required for Li-ion batteries. To overcome the limit of the theoretical energy density in conventional electrode materials based solely on the transition metal redox reaction, the oxygen redox reaction in electrode materials has become an essential component because it can further increase the energy density by providing additional available electrons. However, the increase in the contrib

Ni-rich layered electrode materials have attracted great attention as a promising cathode candidate for high-energy-density lithium-ion batteries because of their high capacity and relatively low cost. However, they have been suffering from severe capacity fading for cycles, which can originate from several factors such as the phase transition at the end of charge and disintegration of the particles. Herein, a simple and novel sublimation-induced gas-reacting (SIGR) process has been developed by