Uichan Hwang

Man Ho Han

Gwangbin Won

Seung-Hyeon Kim

Jina Lee

Ji Hyun Lee

Mi-Ju Kim

Hongju Lee

Seungyun Jeon

Min-Young Kim

Min-Ji Jeong

Min-Jeong Yi

Seong-Jun Kim

Eun-Bi Kim

Chanwoo Koo

Eun-Seo Lee

Mihyun Kim

A-Re Jeon

Minhyung Kwon

Seok Hyun Song

Jin Hwan Kwak

Ban Suk Lee

Ji Hyun Um

Aihua Jin

In-Hwan Ko

Hyejin Jung

Geon-Hee Yoon

The Rechargeable Battery Materials Laboratory focuses on the design and development of novel materials for rechargeable batteries, including Li-ion, Na-ion, Mg-ion, and Li-S batteries. Research emphasizes mechanistic studies of rechargeable battery electrodes utilizing synchrotron X-ray-based operando methods. Nanostructures are designed to achieve high electrochemical performance, capacity, and rate capability.

본 연구실에서는 리튬 이온, 나트륨 이온, 마그네슘 이온 및 리튬-황 배터리와 같은 충전식 배터리에 적용될 새로운 물질의 설계 및 개발에 중점을 둔다. 특히, 싱크로트론 X선 기반 작동법을 사용하여 충전식 배터리 전극의 메커니즘 연구를 수행한다. 나노 구조는 높은 전기화학적 성능, 용량 및 속도 기능을 발휘하도록 설계된다.

Weakly polar organic additive inducing capacity-dependent zinc growth transition via indirect solvation and adsorption engineering in aqueous electrolyte

Metal-organic framework-based ion diffusion regulation layer for aqueous electrolyte zinc metal batteries

Enable high-depth-of-discharge operation of Zn powder anode via conformal SnO2 coating

Degradation pathways of silicon-based anodes in lithium-ion batteries

Design principles for cation-disordered superionic thioantimonate argyrodite solid electrolytes

Reversible redistribution in Ag-Si electrodes for stable anode-free all-solid-state batteries

Redistributing cobalt and tungsten from WC-Co soft scrap toward sustainable cathode and coating materials for lithium-ion batteries

Vacancy-suppressed Garnet electrolytes for durable solid-state batteries

Binding properties of sulfur to enable solvent-free fabrication of high-performance polymer-free sulfur-carbon positive electrodes

Thermally engineered cationic defects in MOF-derived inverse spinel Al 8 [Fe 16-x Mn x ]O 32 for high-energy hybrid supercapacitors

Anion concentration-regulated interface stabilization enabling high-performance lithium metal batteries

A highly durable thin-film assembled membrane for efficient gas crossover suppression in anion exchange membrane water electrolysis

Cosolvent electrolyte design for Li-S batteries: Suppressing the shuttle effect via phase separation

Haloaromatic reduction-induced formation of a high surface work function protective layer on a lithium electrode for stable lithium metal batteries

Revealing the mechanisms behind transient whisker suppression by LiNO 3 in anode-free lithium metal batteries

Galvanic replacement reactions in metal oxide nanocrystals

Conversion reaction‐based oxide nanomaterials for lithium ion battery anodes

Self-Assembled Fe 3 O 4 Nanoparticle Clusters as High-Performance Anodes for Lithium Ion Batteries via Geometric Confinement

Understanding conversion-type electrodes for lithium rechargeable batteries

Edge-exposed MoS 2 nano-assembled structures as efficient electrocatalysts for hydrogen evolution reaction

Highly selective lithium recovery from brine using a λ-MnO 2–Ag battery

In Situ X-ray Absorption Spectroscopy of a Synergistic Co–Mn Oxide Catalyst for the Oxygen Reduction Reaction

Solvothermal‐derived S‐doped graphene as an anode material for sodium‐ion batteries

In situ hydrothermal synthesis of Mn3O4 nanoparticles on nitrogen-doped graphene as high-performance anode materials for lithium ion batteries

Understanding the lithium–sulfur battery redox reactions via operando confocal Raman microscopy

A simple l-cysteine-assisted method for the growth of MoS 2 nanosheets on carbon nanotubes for high-performance lithium ion batteries

Single source precursor-based solvothermal synthesis of heteroatom-doped graphene and its energy storage and conversion applications

Stimulating Cu–Zn alloying for compact Zn metal growth towards high energy aqueous batteries and hybrid supercapacitors

Graphene quantum dots: structural integrity and oxygen functional groups for high sulfur/sulfide utilization in lithium sulfur batteries

Direct visualization of sulfur cathodes: new insights into Li–S batteries via operando X-ray based methods

Regulating Key Variables and Visualizing Lithium Dendrite Growth: An Operando X-ray Study

Continuous activation of Li 2 MnO 3 component upon cycling in Li 1.167 Ni 0.233 Co 0.100 Mn 0.467 Mo 0.033 O 2 cathode material for lithium ion batteries

A chemically activated graphene-encapsulated LiFePO 4 composite for high-performance lithium ion batteries

A facile hydrazine-assisted hydrothermal method for the deposition of monodisperse SnO 2 nanoparticles onto graphene for lithium ion batteries

Design of structural and functional nanomaterials for lithium-sulfur batteries

Yung-Eun Sung

Taeghwan Hyeon

Hector D. Abruna

Nicola Pinna

Kug-Seung Lee

Seung-Keun Park

Dong Young Chung

Kyungjae Lee

Jeesoo Seok

Dong Jun Lee

Junyoung Mun

Kisuk Kang

Seung-Ho Yu

Galvanic replacement reactions provide a simple and versatile route for producing hollow nanostructures with controllable pore structures and compositions. However, these reactions have previously been limited to the chemical transformation of metallic nanostructures. We demonstrated galvanic replacement reactions in metal oxide nanocrystals as well. When manganese oxide (Mn 3 O 4 ) nanocrystals were reacted with iron(II) perchlorate, hollow box-shaped nanocrystals of Mn 3 O 4 /γ-Fe 2 O 3 (“nanoboxes”) were produced. These nanoboxes ultimately transformed into hollow cagelike nanocrystals of γ-Fe 2 O 3 (“nanocages”). Because of their nonequilibrium compositions and hollow structures, these nanoboxes and nanocages exhibited good performance as anode materials for lithium ion batteries. The generality of this approach was demonstrated with other metal pairs, including Co 3 O 4 /SnO 2 and Mn 3 O 4 /SnO 2 .

Developing high‐energy‐density electrodes for lithium ion batteries (LIBs) is of primary importance to meet the challenges in electronics and automobile industries in the near future. Conversion reaction‐based transition metal oxides are attractive candidates for LIB anodes because of their high theoretical capacities. This review summarizes recent advances on the development of nanostructured transition metal oxides for use in lithium ion battery anodes based on conversion reactions. The oxide materials covered in this review include oxides of iron, manganese, cobalt, copper, nickel, molybdenum, zinc, ruthenium, chromium, and tungsten, and mixed metal oxides. Various kinds of nanostructured materials including nanowires, nanosheets, hollow structures, porous structures, and oxide/carbon nanocomposites are discussed in terms of their LIB anode applications.

Although different kinds of metal oxide nanoparticles continue to be proposed as anode materials for lithium ion batteries (LIBs), their cycle life and power density are still not suitable for commercial applications. Metal oxide nanoparticles have a large storage capacity, but they suffer from the excessive generation of solid–electrolyte interphase (SEI) on the surface, low electrical conductivity, and mechanical degradation and pulverization resulted from severe volume expansion during cycling. Herein we present the preparation of mesoporous iron oxide nanoparticle clusters (MIONCs) by a bottom-up self-assembly approach and demonstrate that they exhibit excellent cyclic stability and rate capability derived from their three-dimensional mesoporous nanostructure. By controlling the geometric configuration, we can achieve stable interfaces between the electrolyte and active materials, resulting in SEI formation …

Conspectus The need/desire to lower the consumption of fossil fuels and its environmental consequences has reached unprecedented levels in recent years. A global effort has been undertaken to develop advanced renewable energy generation and especially energy storage technologies, as they would enable a dramatic increase in the effective and efficient use of renewable (and often intermittent) energy sources. The development of electrical energy storage (EES) technologies with high energy and power densities, long life, low cost, and safe use represents a challenge from both the fundamental science and technological application points of view. While the advent and broad deployment of lithium-ion batteries (LIBs) has dramatically changed the EES landscape, their performance metrics need to be greatly enhanced to keep pace with the ever-increasing demands imposed by modern consumer electronics …

Edge-exposed MoS2 nano-assembled structures are designed for high hydrogen evolution reaction activity and long term stability. The number of sulfur edge sites of nano-assembled spheres and sheets is confirmed by Raman spectroscopy and EXAFS analysis. By controlling the MoS2 morphology with the formation of nano-assembled spheres with the assembly of small-size fragments of MoS2, the resulting assembled spheres have high electrocatalytic HER activity and high thermodynamic stability.

The demand for lithium has greatly increased with the rapid development of rechargeable batteries. Currently, the main lithium resource is brine lakes, but the conventional lithium recovery process is time consuming, inefficient, and environmentally harmful. Rechargeable batteries have been recently used for lithium recovery, and consist of lithium iron phosphate as a cathode. These batteries feature promising selectivity between lithium and sodium, but they suffer from severe interference from coexisting magnesium ions, an essential component of brine, which has prompted further study. This study reports on a highly selective and energy-efficient lithium recovery system using a rechargeable battery that consists of a λ-MnO2 positive electrode and a chloride-capturing negative electrode. This system can be used to recover lithium from brine even in the presence of magnesium ions as well as other dissolved …

Identifying the catalytically active site(s) in the oxygen reduction reaction (ORR), under real-time electrochemical conditions, is critical to the development of fuel cells and other technologies. We have employed in situ synchrotron-based X-ray absorption spectroscopy (XAS) to investigate the synergistic interaction of a Co–Mn oxide catalyst which exhibits impressive ORR activity in alkaline fuel cells. X-ray absorption near edge structure (XANES) was used to track the dynamic structural changes of Co and Mn under both steady state (constant applied potential) and nonsteady state (potentiodynamic cyclic voltammetry, CV). Under steady state conditions, both Mn and Co valences decreased at lower potentials, indicating the conversion from Mn(III,IV) and Co(III) to Mn(II,III) and Co(II), respectively. Rapid X-ray data acquisition, combined with a slow sweep rate in CV, enabled a 3 mV resolution in the applied potential …

Sodium‐ion batteries (SIBs) have attracted enormous attention in recent years due to the high abundance and low cost of sodium. However, in contrast to lithium‐ion batteries, conventional graphite is unsuitable for SIB anodes because it is much more difficult to intercolate the larger Na ions into graphite layers. Therefore, it is critical to develop new anode materials for SIBs for practical use. Here, heteroatom‐doped graphene with high doping levels and disordered structures is prepared using a simple and economical thermal process. The solvothermal‐derived graphene shows excellent performance as an anode material for SIBs. It exhibits a high reversible capacity of 380 mAh g −1 after 300 cycles at 100 mA g −1 , excellent rate performance 217 mAh g −1 at 3200 mA g −1 , and superior cycling performance at 2.0 A g −1 during 1000 cycles with negligible capacity fade.

Developing new electrode materials with high specific capacity for excellent lithium ion storage properties is very desirable. In this paper, we introduce a simple hydrothermal method for the growth of Mn 3 O 4 nanoparticles onto nitrogen-doped graphene (N-doped graphene) for high-performance lithium ion battery (LIB) anodes. Hydrazine plays a fundamental role in the formation of such nanostructures as it can act both as a reducing agent and as a nitrogen source. In the synthesized composite, highly crystalline Mn 3 O 4 nanoparticles with average sizes of 20–50 nm are homogeneously dispersed on both sides of the N-doped graphene. The nitrogen content in the doped graphene is confirmed by elemental analyzer, and 2 wt% of the sample is found to be composed of nitrogen element. The as-prepared Mn 3 O 4 /N-doped graphene composites exhibit remarkable electrochemical performance, including high …

The complex interplay and only partial understanding of the multi-step phase transitions and reaction kinetics of redox processes in lithium–sulfur batteries are the main stumbling blocks that hinder the advancement and broad deployment of this electrochemical energy storage system. To better understand these aspects, here we report operando confocal Raman microscopy measurements to investigate the reaction kinetics of Li–S redox processes and provide mechanistic insights into polysulfide generation/evolution and sulfur deposition. Operando visualization and quantification of the reactants and intermediates enabled the characterization of potential-dependent rates during Li–S redox and the linking of the electronic conductivity of the sulfur-based electrode and concentrations of polysulfides to the cell performance. We also report the visualization of the interfacial evolution and diffusion processes of different …

We introduce a simple process to synthesize few-layered MoS2 nanosheets supported on coaxial carbon nanotubes through an L-cysteine-assisted hydrothermal route, in which L-cysteine, a cheap and ordinary amino acid, plays a fundamental role in controlling the morphology of the hybrid material and the binder to help the growth of MoS2 nanosheets on the surface of the carbon nanotubes. It is also demonstrated that the polypeptide formed by L-cysteine can be transformed into amorphous carbon by heat treatment under an inert atmosphere. The materials exhibit high capacity and excellent cycling performance when used as anode materials for lithium ion batteries. The specific capacity of a composite with 1 : 4 molar ratio of MoS2 to carbon nanotubes is 736.5 mAh g−1 after the first cycle, increased for several initial cycles, and remains at 823.4 mAh g−1 even after 30 cycles, when cycled at a current density …

Solvothermal processes are considered efficient approaches for the gram-scale production of graphene. Further modification of graphene by chemical doping is an important approach to tailor its properties. In this work, we successfully synthesized sulfur-doped graphene by using a solvothermal method with dimethyl sulfoxide as a precursor, which is a common laboratory reagent. Nitrogen-doped graphene was produced to demonstrate the generality of this process. These heteroatom-doped graphene materials exhibited high surface areas and high contents of heteroatoms. Furthermore, the lithium-ion storage properties and oxygen reduction reaction catalytic activity of these materials were also investigated. The success of this approach might facilitate the development of other advanced graphene-based materials with relative simplicity, scalability and cost effectiveness for use in various potential applications.

Aqueous Zn-ion batteries (AZIBs) ensure unparalleled safety for large-scale energy storage applications. However, developing highly reversible zinc metal anodes with finite capacity is a prerequisite to realizing the performance characteristics of AZIBs comparable to those of commercial batteries. Herein, we address this issue by identifying the growth mechanism of densely packed micrometer-sized Zn particles on Cu foil to construct a stable anode with a proper Zn loading for AZIBs. Using various characterization techniques, we demonstrate that deep eutectic solvents activate an unusual Cu–Zn alloying reaction to produce a Zn-rich alloy interlayer that is zincophilic and isotypic to the pure Zn phase. This alloy layer, in turn, forms compact Zn deposits of which structure can endure continuous cycling in an aqueous electrolyte, effectively preventing AZIB corrosion and swelling. Owing to the high reversibility of the …

Lithium–sulfur (Li–S) batteries are expected to overcome the limit of current energy storage devices by delivering high specific energy with low material cost. However, the potential of Li–S batteries has not yet been realized because of several technical barriers. Poor electrochemical performance is mainly attributed to the low electrical conductivity of the fully charged and discharged species, the irreversible loss of polysulfide anions and the decrease in the number of electrochemically active reaction sites during battery operation. Here, we report that the introduction of graphene quantum dots (GQDs) into the sulfur cathode dramatically enhanced sulfur/sulfide utilization, yielding high performance. In addition, the GQDs induced structural integrity of the sulfur–carbon electrode composite by oxygen-rich functional groups. This hierarchical architecture enabled fast charge transfer while minimizing the loss of lithium …

As the need for the development of “beyond lithium” ion battery technologies continues unabated, lithium sulfur batteries have attracted widespread attention due to their very high theoretical energy density of 2600 W h kg−1. However, despite much effort, the detailed reaction mechanism remains poorly understood. In this study, we have combined operando X-ray diffraction and X-ray microscopy along with X-ray tomography, to visualize the evolution of both the morphology and crystal structure of the materials during the entire battery cycling (discharging/charging) process. The dissolution and reformation of sulfur clusters is clearly observed during cycling. In addition, we demonstrate, for the first time, the critical role of current density and temperature in determining the size of both the resulting sulfur clusters and Li2S particles. This study provides new insights about promising avenues for the continued …

Although Li metal has long been considered to be the ideal anode material for Li rechargeable batteries, our limited understanding of the complex mechanism of Li plating has hindered the widespread deployment of Li metal anodes. Therefore, operando studies are required to unambiguously reveal the complex mechanistic steps involved. In this study, we employed synchrotron-based X-ray imaging methods to visualize the evolution of Li plating/stripping under operando and, more importantly, practical conditions for battery operation, providing detailed insights into morphology evolution during Li plating. The effects of critical battery operating parameters, including concentration of Li salts, current density, ionic strength, and various electrolytes and additives, on Li plating/stripping have been studied. The delicate interplay of these conditions on the resulting Li metal morphology has been characterized for the first …

Li-rich layered cathode materials are very promising candidates for next generation high energy lithium ion batteries. One of the Li-rich layered cathode materials, Li1.167Ni0.233Co0.100Mn0.467Mo0.033O2 is prepared by a co-precipitation method. In this report, we focus on anomalous changes upon cycling in Li1.167Ni0.233Co0.100Mn0.467Mo0.033O2 cathode material in a voltage range of 2.0–4.55 V at room temperature. The structural transitions upon cycling are analyzed by ex situ X-ray diffraction. In addition, the changes in local structure during cycling are studied by X-ray absorption near edge structure. With differential capacity plots by controlling the cut-off voltage, the voltage decay during cycling is intensively studied. The continuous activation process of the residual Li2MnO3 component during cycling is correlated with voltage decay during cycling, and increasing capacity during the initial several …

A composite of modified graphene and LiFePO4 has been developed to improve the speed of charging–discharging and the cycling stability of lithium ion batteries using LiFePO4 as a cathode material. Chemically activated graphene (CA-graphene) has been successfully synthesized via activation by KOH. The as-prepared CA-graphene was mixed with LiFePO4 to prepare the composite. Microscopic observation and nitrogen sorption analysis have revealed the surface morphologies of CA-graphene and the CA-graphene/LiFePO4 composite. Electrochemical properties have also been investigated after assembling coin cells with the CA-graphene/LiFePO4 composite as a cathode active material. Interestingly, the CA-graphene/LiFePO4 composite has exhibited better electrochemical properties than the conventional graphene/LiFePO4 composite as well as bare LiFePO4, including exceptional speed of charging …

In this manuscript, we introduce a facile hydrothermal method for the controlled growth of SnO2 nanoparticles onto graphene oxide. Hydrazine plays a fundamental role in controlling the formation and crystallization of SnO2 nanoparticles, and the reduction of graphene oxide to graphene. The SnO2–graphene composite consists of 3–4 nm monodisperse SnO2 nanocrystals homogeneously dispersed at the surface of graphene. It is demonstrated that the composite can accommodate the large volume change of SnO2 which occurs during lithiation–delithiation cycles. When used as an anode material for lithium ion batteries, it exhibits a first discharge capacity of 1662 mA h g−1, which rapidly stabilizes and still remains at 626 mA h g−1 even after 50 cycles, when cycled at a current density of 100 mA g−1. Even at the very high current density of 3200 mA g−1, the composite displays a stable capacity of 383 mA h g−1 …

Over the last decade, lithium–sulfur (Li–S) batteries have been extensively studied because of the abundance of sulfur, their environmental benignity, and high gravimetric (2600 W h kg −1 ) and volumetric (2800 W h L −1 ) energy densities. However, their unique electrochemical behavior involving the formation of dissolved polysulfide intermediate species and the insulating nature of sulfur and Li 2 S are the main drawbacks that must still be overcome. To tackle these limitations, solutions such as appropriate cathode architecture design, electrolyte optimization, and lithium metal stabilization have been proposed. Recently, high areal sulfur loading, a high sulfur content, and a high electrolyte-to-sulfur ratio have also become prominent issues for the commercialization of the Li–S batteries. This paper reviews a wide range of reports on the design of structural and functional nanomaterials for Li–S batteries and …

Electrochemical Energy Laboratory

교수님 소개

유승호

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Weakly polar organic additive inducing capacity-dependent zinc growth transition via indirect solvation and adsorption engineering in aqueous electrolyte

Metal-organic framework-based ion diffusion regulation layer for aqueous electrolyte zinc metal batteries

Enable high-depth-of-discharge operation of Zn powder anode via conformal SnO2 coating

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

유승호

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

Weakly polar organic additive inducing capacity-dependent zinc growth transition via indirect solvation and adsorption engineering in aqueous electrolyte

Metal-organic framework-based ion diffusion regulation layer for aqueous electrolyte zinc metal batteries

Enable high-depth-of-discharge operation of Zn powder anode via conformal SnO2 coating

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집