Hongkyung Lee

A modified Prussian blue analogue, Na(2)Zn(3)[Fe(CN)(6)](2)·xH(2)O, was investigated as a positive electrode material. Utilizing a well-defined channel structure, the compound exhibits a clear electrochemical activity at around 3.5 V vs. Na/Na(+) with a reversible capacity of 56.4 mA h g(-1) and good cycle life.

Abstract Lithium (Li) metal is one of the most promising candidates for the anode in high‐energy‐density batteries. However, Li dendrite growth induces a significant safety concerns in these batteries. Here, a multifunctional separator through coating a thin electronic conductive film on one side of the conventional polymer separator facing the Li anode is proposed for the purpose of Li dendrite suppression and cycling stability improvement. The ultrathin Cu film on one side of the polyethylene

Abstract Ionic liquid (IL) electrolytes with concentrated Li salt can ensure safe, high‐performance Li metal batteries (LMBs) but suffer from high viscosity and poor ionic transport. A locally concentrated IL (LCIL) electrolyte with a non‐solvating, fire‐retardant hydrofluoroether (HFE) is presented. This rationally designed electrolyte employs lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 1‐methyl‐1‐propyl pyrrolidinium bis(fluorosulfonyl)imide (P13FSI) and 1,1,2,2‐tetrafluoroethyl 2,2,3

Interfacial stability is one of the crucial factors for long-term cyclability of lithium (Li) metal batteries (LMBs). While cross-contamination phenomena have been well-studied in Li-ion batteries (LIBs), similar phenomena have rarely been reported in LMBs. Here, we investigated cathode failure triggered by chemical crossover from the anode in LMBs. In contrast to LIBs, the cathode in LMBs suffers more significant capacity fading, and its capacity cannot be fully recovered by replacing the Li an

Abstract Making Li metal batteries (LMBs) with thinner Li is necessary to improve the cell energy density in practice. Li metal powders (LMPs) are beneficial for the facile manufacturing of thin Li, flexible cell design, and the 3D control of Li plating/stripping. However, the inhomogeneous surfaces of commercial LMPs limit their practical use in LMBs. Herein, a 20 µm‐thick, LiNO 3 preplanted LMP (LN‐LMP) composite electrode, rationally designed for LMP surface stabilization, is presented. The a

The problem of carbon and binder decomposition, degrading the performance levels of the cathodes used in lithium–oxygen (Li–O2) batteries, remains unsolved. For this reason, using carbon and binder-free cathodes may be an ideal approach to remedy this problem. Here, we have developed a carbon free- and binder-free cathode for Li–O2 batteries based on vertically grown Co3O4 nanowire (NW) arrays on Ni-foam and demonstrated the suppression of this type of decomposition. The highly organized texture

The use of lithium (Li) metal anodes has been reconsidered because of the necessity for a higher energy density in secondary batteries. However, Li metal anodes suffer from 'dead' Li formation and surface deactivation which consequently form a porous layer of redundant Li aggregates. In this work, a fibrous metal felt (FMF) as a three-dimensional conductive interlayer was introduced between the separator and the Li metal anode to improve the reversibility of the Li metal anode. The FMF can facil

Developing a safe and long-lasting lithium (Li) metal battery is crucial for high-energy applications. However, its poor cycling stability due to Li dendrite formation and excessive Li pulverization is the major hurdle for its practical applications. Here, we present a silica (SiO₂) nanoparticle-dispersed colloidal electrolyte (NDCE) and its design principle for suppressing Li dendrite formation. SiO₂ nanoclusters in the NDCE play roles in enhancing the Li⁺ trans

Abstract The very high specific capacity of Li metal makes it an ideal anode for high‐energy batteries. However, Li dendrite growth and the formation of isolated (or “dead”) Li during repeated Li plating/stripping processes leads to a low coulombic efficiency (CE). In this work, we discovered, for the first time, that electrode edge effects play an important role in the failure of Li‐metal batteries. The dead Li formed on the edge of Cu substrate was systematically investigated through SEM, ener

Abstract Despite the promises in high‐energy‐density batteries, Li‐metal anodes (LMAs) have suffered from extensive electrolyte decomposition and unlimited volume expansion owing to thick, porous layer buildup during cycling. It mainly originates from a ceaseless reiteration of the formation and collapse of solid‐electrolyte interphase (SEI). This study reveals the structural and chemical evolutions of the reacted Li layer after different cycles and investigates its detrimental effects on the cy

We present a synergistic strategy to boost the cycling performance of Li-metal batteries. The strategy is based on the combined use of a micropattern (MP) on the surface of the Li-metal electrode and an advanced dual-salt electrolyte (DSE) system to more efficiently control undesired Li-metal deposition at higher current density (∼3 mA cm^-2). The MP-Li electrode induces a spatially uniform current distribution to achieve dendrite-free Li-metal deposition beneath the surface layer form