Hyeon Jeong Lee

The oxygen evolution reaction (OER) constitutes the key limiting process in water electrolysis, and various catalysts have recently been introduced to improve OER efficiency. Vacancy engineering in the crystal lattice is particularly promising in catalyst design, as vacancies could perturb the electronic properties of adjacent atoms to make them catalytically active. Noting that one of the well-adopted approaches to induce vacancies in a crystal structure is the mixing of elements with different

Abstract The intrinsic limitations of lithium‐ion batteries (LIBs) with regard to safety, cost, and the availability of raw materials have promoted research on so‐called “post‐LIBs”. The recent intense research of post‐LIBs provides an invaluable lesson that existing electrode materials used in LIBs may not perform as well in post‐LIBs, calling for new material designs compliant with emerging batteries based on new chemistries. One promising approach in this direction is the development of mater

Li 2 OHCl 0.9 Br 0.1 exhibits the highest Li-ion conductivity in Li 2 OHCl 1− x Br x material system due to the combined effect of its defective structure and reduced grain boundary resistance.

Solid-state batteries (SSBs) have received attention as a next-generation energy storage technology due to their potential to superior deliver energy density and safety compared to commercial Li-ion batteries. One of the main challenges limiting their practical implementation is the rapid capacity decay caused by the loss of contact between the cathode active material and the solid electrolyte upon cycling. Here, we use the promising high-voltage, low-cost LiNi_0.5Mn_1.5O<sub

The high-voltage (4.7 V vs Li+/Li) spinel lithium nickel manganese oxide (LiNi0.5Mn1.5O4, LNMO) is a promising candidate for the next generation of lithium-ion batteries due to its high energy density, low cost, and low environmental impact. However, poor cycling performance at high cutoff potentials limits its commercialization. Herein, hollow-structured LNMO is synergistically paired with an ionic liquid electrolyte, 1 M lithium bis(fluorosulfonyl)imide (LiFSI) in N-propyl-N-methylpyrrolidiniu

Anomalously high pseudocapacitance of a metal oxide was observed when Ni, Co, and Mn were mixed in a solid solution. Analysis by X-ray absorption near-edge spectroscopy (XANES) identified a wider redox swing of Ni as the origin of the enlarged pseudocapacitance. Ab initio DFT calculations revealed that aliovalent species resulting from the copresence of multiple transition metals can generate permanent local distortions of [NiO6] octahedra. As this type of distortion breaks the degenerate eg lev

Transition metal (TM) based Prussian whites, comprising a cyanide anion ((C≡N) − ) and TM cations in an alternative manner, have been widely adopted as cathode materials for rechargeable batteries. Prussian whites are characterized by the TM electronic states that exclusively adopt low spin (LS) toward the C atom and high spin (HS) toward the N atom through the hybridized covalent bonding in the TM─C≡N─TM unit with the average oxidation states of the TM ions being 2+, considerably affecting the

, LCO), which serves as a structural motif for the widely adopted layered cathodes in lithium-ion batteries, has a long history, and its unstable phase transition during high-voltage operation (∼4.5 V) remains an intractable problem. Many research strategies, such as surface coating and immobile ion doping, have been proposed to address this issue, but a clear understanding of the effects has not been demonstrated because of various potential parameters (e.g., particle size, shape, and dopant co

Abstract Single‐crystal cathodes have been investigated for their inherent resistance to intergranular cracking due to the absence of grain boundaries. However, these materials exhibit significant intragranular cracking, and the underlying mechanisms remain unclear. In this study, we examined the impact of extended solid‐solution reactions on mitigating crack formation in magnesium‐doped single‐crystal LiNi 0.5 Mn 1.5 O 4 (Mg‐SC‐LNMO) cathodes. With Mg acting as a structural pillar, the overall

In situ X-ray characterization and DFT calculations reveal that Ni configuration and N-coordination modulate the binding energies of *COOH and *H intermediates, with their difference being key to predicting CO 2 RR activity on Ni single atomic sites.

High-voltage spinel-type lithium nickel manganese oxide (LiNi 0.5 Mn 1.5 O 4, LNMO) is considered a promising cathode material for lithium-ion batteries due to its high operating voltage (∼4.7 V vs Li/Li + ) and cobalt-free composition, which enables it to deliver approximately 1.5 times higher energy-to-cost efficiency compared to lithium nickel cobalt manganese oxides (NCM). Although LNMO was among the earliest high-voltage cathode materials studied, it has attracted less commercial attention

One-pot synthesized Berlin green cubes exhibit enhanced rate capability and cycle life when employed as a lithium-ion battery cathode.

Abstract Intercalation and deintercalation are fundamental processes in battery electrodes that involve the reversible addition and extraction of carrier ions such as lithium (Li) and sodium (Na) into a host framework made of transition metal (TM) ions and ligands. Although TM–ligand interactions are known to primarily determine intercalation potentials, a comprehensive understanding of their interactions involving the carrier ions still remains elusive. This study investigates the complex inter