고려대학교 차세대에너지저장소재연구실 (AMESL)
Advanced Materials for Energy Storage Lab

[Invited] Decoding the Structural Controversy of Li- and Mn-Rich Cathodes Through Synthesis-Dependent Domain Evolution

Uniform pore structure enables negligible degradation in undoped and uncoated Ni-rich cathodes

Revitalizing multifunctionality of Li-Al-O system enabling mother-powder-free sintering of garnet-type solid electrolytes

Realizing Li Concentration and Particle Size Gradients in Ni-Rich Cathode for Superior Electrochemical Performance in Oxygen-Deficient Atmospheres

Multi-scale defect regulation of cobalt-free layered oxides for high-energy and long-lasting cathodes

Enhanced densification of garnet-type solid electrolytes under oxygen-enriched sintering atmosphere

Activation of Oxygen Redox by Inhibited Dynamic Phase Transition for High-Energy Li-Rich Layered Oxide Cathode

Unraveling and regulating superstructure domain dispersion in lithium-rich layered oxide cathodes for high stability and reversibility

Structurally robust lithium-rich layered oxides for high-energy and long-lasting cathodes

Toward a Nanoscale‐Defect‐Free Ni‐Rich Layered Oxide Cathode Through Regulated Pore Evolution for Long‐Lifespan Li Rechargeable Batteries

A Full Oxide-Based Solid-State Lithium Battery and Its Unexpected Cathode Degradation Mechanism

Redox mediators for oxygen reduction reactions in lithium–oxygen batteries: Governing kinetics and its implications

Amorphous iron fluorosulfate as a high-capacity cathode utilizing combined intercalation and conversion reactions with unexpectedly high reversibility

High-energy and long-lasting organic electrode for a rechargeable aqueous battery

In situ multiscale probing of the synthesis of a Ni-rich layered oxide cathode reveals reaction heterogeneity driven by competing kinetic pathways

Coupling structural evolution and oxygen-redox electrochemistry in layered transition metal oxides

High-dielectric polymer coating for uniform lithium deposition in anode-free lithium batteries

Liquid‐Based Janus Electrolyte for Sustainable Redox Mediation in Lithium–Oxygen Batteries

A p–n fusion strategy to design bipolar organic materials for high-energy-density symmetric batteries

Probing Lithium Metals in Batteries by Advanced Characterization and Analysis Tools

Permselective metal–organic framework gel membrane enables long-life cycling of rechargeable organic batteries

Tailoring Ion-Conducting Interphases on Magnesium Metals for High-Efficiency Rechargeable Magnesium Metal Batteries

Dual‐Functioning Molecular Carrier of Superoxide Radicals for Stable and Efficient Lithium–Oxygen Batteries

Controlling residual lithium in high‐nickel (> 90%) lithium layered oxides for cathodes in lithium‐ion batteries

Anionic Redox Activity Regulated by Transition Metal in Lithium‐Rich Layered Oxides

Voltage decay and redox asymmetry mitigation by reversible cation migration in lithium-rich layered oxide electrodes

Anchored mediator enabling shuttle–free redox mediation in lithium–oxygen batteries

Enhancing the Cycle Stability of Li-O2 Batteries via Functionalized Carbon Nanotube-based Electrodes

Stable and High‐Power Calcium‐Ion Batteries Enabled by Calcium Intercalation into Graphite

Enhancing bi-functional catalytic activity via a nanostructured La (Sr) Fe (Co) O3-δ@ Pd matrix as an efficient electroctalyst for rechargeable Li-O2 batteries

A bifunctional auxiliary electrode for safe lithium metal batteries

Biological Nicotinamide Cofactor as a Redox‐Active Motif for Reversible Electrochemical Energy Storage

Toward a low-cost high-voltage sodium aqueous rechargeable battery

Investigation of Li-O2 Battery Performance Integrated with RuO2 Inverse Opal Cathodes in DMSO

고안정성 고체전해질 제조 기술

XRD-Raman 듀얼 오페란도 측정시스템

레독스 흐름 전지용 분리막, 그 제조 방법 및 레독스 흐름 전지

산화물계 고체전해질 및 그 제조방법

보조전극 센서를 포함하는 이차전지 및 이차전지의 이상 검출 방법

리튬 이차전지용 전해질 및 이를 포함하는 리튬 이차전지

액체 촉매가 포함된 충전가능한 리튬-이산화황 전지

고안정성 산화물계 고체전해질용 분말, 이를 포함하는 고안정성 산화물계 고체전해질 및 그 제조방법

기계화학적 질화리튬 합성 방법

인시츄 전기화학 전처리를 이용한 무음극 전지의 제조방법 및 이에 의해 제조되는 무음극 전지

전기화학반응 스캐닝 셀 및 그를 포함하는 전기화학반응 스캐닝 시스템

산화물계 양극 복합체 및 그 제조방법

리튬 이차 전지용 음극 및 이를 포함하는 리튬 이차 전지

리튬공기전지의 양극재료 및 이를 이용한 양극 제조방법

Reaction chemistry in rechargeable Li–O2 batteries

Tailoring sodium intercalation in graphite for high energy and power sodium ion batteries

Abnormal self-discharge in lithium-ion batteries

Dissolution and ionization of sodium superoxide in sodium–oxygen batteries

Calcium‐Ion Batteries: Stable and High‐Power Calcium‐Ion Batteries Enabled by Calcium Intercalation into Graphite (Adv. Mater. 4/2020)

Suppression of Voltage Decay through Manganese Deactivation and Nickel Redox Buffering in High‐Energy Layered Lithium‐Rich Electrodes

Anisotropic Surface Modulation of Pt Catalysts for Highly Reversible Li–O2 Batteries: High Index Facet as a Critical Descriptor

Redox Mediators: A Solution for Advanced Lithium–Oxygen Batteries

Direct Observation of Redox Mediator-Assisted Solution-Phase Discharging of Li–O2 Battery by Liquid-Phase Transmission Electron Microscopy

Biological redox mediation in electron transport chain of bacteria for oxygen reduction reaction catalysts in lithium–oxygen batteries

Kisuk Kang

Youngmin Ko

Youngjoon Bae

Won Mo Seong

Myeong Hwan Lee

Jinsoo Kim

Gabin Yoon

Orapa Tamwattana

Byungju Lee

Kyu-Young Park

Hee-Dae Lim

Hyungsub Kim

Sung-Kyun Jung

Haegyeom Kim

Kyojin Ku

Jungwon Park

Jihyun Hong

Hyung-Kyu Lim

Hyungjun Kim

Hyeokjun Park

Despite the high energy density of lithium-rich layered-oxide electrodes, their real-world implementation in batteries is hindered by the substantial voltage decay on cycling. This voltage decay is widely accepted to mainly originate from progressive structural rearrangements involving irreversible transition-metal migration. As prevention of this spontaneous cation migration has proven difficult, a paradigm shift toward management of its reversibility is needed. Herein, we demonstrate that the reversibility of the cation migration of lithium-rich nickel manganese oxides can be remarkably improved by altering the oxygen stacking sequences in the layered structure and thereby dramatically reducing the voltage decay. The preeminent intra-cycle reversibility of the cation migration is experimentally visualized, and first-principles calculations reveal that an O2-type structure restricts the movements of transition metals within …

The seemingly simple reaction of Li–O2 batteries involving lithium and oxygen makes this chemistry attractive for high-energy-density storage systems; however, achieving this reaction in practical rechargeable Li–O2 batteries has proven difficult. The reaction paths leading to the final Li2O2 discharge products can be greatly affected by the operating conditions or environment, which often results in major side reactions. Recent research findings have begun to reveal how the reaction paths may be affected by the surrounding conditions and to uncover the factors contributing to the difficulty in achieving the reactions of lithium and oxygen. This progress report describes the current state of understanding of the electrode reaction mechanisms in Li–O2 batteries; the factors that affect reaction pathways; and the effect of cell components such as solvents, salts, additives, and catalysts on the discharge product and its …

Co-intercalation reactions make graphite as promising anodes for sodium ion batteries, however, the high redox potentials significantly lower the energy density. Herein, we investigate the factors that influence the co-intercalation potential of graphite and find that the tuning of the voltage as large as 0.38 V is achievable by adjusting the relative stability of ternary graphite intercalation compounds and the solvent activity in electrolytes. The feasibility of graphite anode in sodium ion batteries is confirmed in conjunction with Na 1.5 VPO 4.8 F 0.7 cathodes by using the optimal electrolyte. The sodium ion battery delivers an improved voltage of 3.1 V, a high power density of 3863 W kg −1 both electrodes , negligible temperature dependency of energy/power densities and an extremely low capacity fading rate of 0.007% per cycle over 1000 cycles, which are among the best thus far reported for sodium ion full cells, making …

Lattice oxygen redox offers an unexplored way to access superior electrochemical properties of transition metal oxides (TMOs) for rechargeable batteries. However, the reaction is often accompanied by unfavourable structural transformations and persistent electrochemical degradation, thereby precluding the practical application of this strategy. Here we explore the close interplay between the local structural change and oxygen electrochemistry during short- and long-term battery operation for layered TMOs. The substantially distinct evolution of the oxygen-redox activity and reversibility are demonstrated to stem from the different cation-migration mechanisms during the dynamic de/intercalation process. We show that the π stabilization on the oxygen oxidation initially aids in the reversibility of the oxygen redox and is predominant in the absence of cation migrations; however, the π-interacting oxygen is gradually …

Recent discovery of high-concentration electrolyte systems has opened a new avenue toward the high-voltage, safe, and low-cost aqueous rechargeable batteries. However, the need for generally high-cost organic solutes in the high-concentration electrolyte has become another major obstacle. Herein, we revisited all the commonly used low-cost solutes for high-concentration system and discovered that the use of NaClO 4 solute effectively results in a wide electrochemical stability window by suppressing water decomposition and induces stable solid-electrolyte interphase (SEI) layer formation without involving the reduction of salt anions. The SEI layer, composed of Na 2 CO 3 and Nasingle bondO compounds including NaOH, guarantees the excellent electrochemical storage stability of the full-cell composed of Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ) cathode and NaTi 2 (PO 4 ) 3 anode for the extended period of time. This new class …

Lithium-ion batteries are expected to serve as a key technology for large-scale energy storage systems (ESSs), which will help satisfy recent increasing demands for renewable energy utilization. Besides their promising electrochemical performance, the low self-discharge rate (<5% of the stored capacity over 1 month) of lithium-ion batteries is one of their most significant advantages for ESSs. Herein, contrary to conventional belief, we report that the self-discharge of LIBs can be abnormally accelerated when the battery has been exposed even to a routine short-term thermal exposure. We demonstrate that this thermal ‘history’ in addition to the temperature itself is memorized in the battery and accelerates the self-discharge rate. The series of characterizations performed in our work reveal that the electrolyte salt acts as a strong oxidizing agent by vigorously damaging the surface of the cathode, producing an internal …

Rechargeable organic batteries show great potential as a low-cost, sustainable and mass-producible alternatives to current transition-metal-based cells; however, serious electrode dissolution issues and solubilization of organic redox intermediates (shuttle effect) have plagued the capacity retention and cyclability of these cells. Here we report on the use of a metal–organic framework (MOF) gel membrane as a separator for organic batteries. The homogeneous micropores, intrinsic of the MOF-gel separator, act as permselective channels for targeted organic intermediates, thereby mitigating the shuttling problem without sacrificing power. A battery using a MOF-gel separator and 5,5′-dimethyl-2,2′-bis- p -benzoquinone (Me 2 BBQ) as the electrode displays high cycle stability with capacity retention of 82.9% after 2,000 cycles, corresponding to a capacity decay of ~0.008% per cycle, with a discharge capacity of …

Nickel-rich layered oxides are envisaged as key near-future cathode materials for high-energy lithium-ion batteries. However, their practical application has been hindered by their inferior cycle stability, which originates from chemo-mechanical failures. Here we probe the solid-state synthesis of LiNi 0.6 Co 0.2 Mn 0.2 O 2 in real time to better understand the structural and/or morphological changes during phase evolution. Multi-length-scale observations—using aberration-corrected transmission electron microscopy, in situ heating transmission electron microscopy and in situ X-ray diffraction—reveal that the overall synthesis is governed by the kinetic competition between the intrinsic thermal decomposition of the precursor at the core and the topotactic lithiation near the interface, which results in spatially heterogeneous intermediates. The thermal decomposition leads to the formation of intergranular voids and …

With the demand for high-energy-storage devices, the rechargeable metal–oxygen battery has attracted attention recently. Sodium–oxygen batteries have been regarded as the most promising candidates because of their lower-charge overpotential compared with that of lithium–oxygen system. However, conflicting observations with different discharge products have inhibited the understanding of precise reactions in the battery. Here we demonstrate that the competition between the electrochemical and chemical reactions in sodium–oxygen batteries leads to the dissolution and ionization of sodium superoxide, liberating superoxide anion and triggering the formation of sodium peroxide dihydrate (Na 2 O 2 ·2H 2 O). On the formation of Na 2 O 2 ·2H 2 O, the charge overpotential of sodium–oxygen cells significantly increases. This verification addresses the origin of conflicting discharge products and overpotentials …

Graphite is realized as a reliable anode material for calcium-ion batteries by Kisuk Kang and co-workers, as described in article number 1904411. By selecting a suitable dimethylacetamide-based electrolyte, Ca ions (de) intercalate into graphite at room temperature with large Ca-storage capacities, remarkable reversibility, and exceptionally high rate capability. This work provides a promising pathway toward the realization of high-power and long-lasting calcium-ion batteries.

The rampant generation of lithium hydroxide and carbonate impurities, commonly known as residual lithium, is a practical obstacle to the mass‐scale synthesis and handling of high‐nickel (>90 %) layered oxides and their use as high‐energy‐density cathodes for lithium‐ion batteries. Herein, we suggest a simple in situ method to control the residual lithium chemistry of a high‐nickel lithium layered oxide, Li(Ni 0.91 Co 0.06 Mn 0.03 )O 2 (NCM9163), with minimal side effects. Based on thermodynamic considerations of the preferred reactions, we systematically designed a synthesis process that preemptively converts residual Li 2 O (the origin of LiOH and Li 2 CO 3 ) into a more stable compound by injecting reactive SO 2 gas. The preformed lithium sulfate thin film significantly suppresses the generation of LiOH and Li 2 CO 3 during both synthesis and storage, thereby mitigating slurry gelation and gas evolution and …

Calcium‐ion batteries (CIBs) are considered to be promising next‐generation energy storage systems because of the natural abundance of calcium and the multivalent calcium ions with low redox potential close to that of lithium. However, the practical realization of high‐energy and high‐power CIBs is elusive owing to the lack of suitable electrodes and the sluggish diffusion of calcium ions in most intercalation hosts. Herein, it is demonstrated that calcium‐ion intercalation can be remarkably fast and reversible in natural graphite, constituting the first step toward the realization of high‐power calcium electrodes. It is shown that a graphite electrode exhibits an exceptionally high rate capability up to 2 A g −1 , delivering ≈75% of the specific capacity at 50 mA g −1 with full calcium intercalation in graphite corresponding to ≈97 mAh g −1 . Moreover, the capacity stably maintains over 200 cycles without notable cycle …

Cobalt‐free layered lithium‐rich nickel manganese oxides, Li[Li x Ni y Mn 1− x − y ]O 2 (LLNMO), are promising positive electrode materials for lithium rechargeable batteries because of their high energy density and low materials cost. However, substantial voltage decay is inevitable upon electrochemical cycling, which makes this class of materials less practical. It has been proposed that undesirable voltage decay is linked to irreversible structural rearrangement involving irreversible oxygen loss and cation migration. Herein, the authors demonstrate that the voltage decay of the electrode is correlated to Mn 4+ /Mn 3+ redox activation and subsequent cation disordering, which can be remarkably suppressed via simple compositional tuning to induce the formation of Ni 3+ in the pristine material. By implementing our new strategy, the Mn 4+ /Mn 3+ reduction is subdued by an alternative redox reaction involving the use of …

The use of lithium metal either in an anode or anode-free configuration is envisaged as the most promising way to boost the energy density of the current lithium-ion battery system. Nevertheless, the uncontrolled lithium dendritic growth inhibits practical utilization of lithium metal as an anode due to safety concerns and low Coulombic efficiency. In this work, we show that when a high-dielectric SEI is coated on a current collector, it can effectively promote a uniform lithium deposition by decreasing the overpotential between the surfaces, lowering the local current density and suppressing lithium protrusions. Using a PVDF (polyvinylidene difluoride)-based dielectric medium, it is demonstrated that varying the dielectric properties of PVDF by crystallinity control can regulate the lithium deposition mechanisms. Moreover, when the dielectric properties of PVDF film are tailored by the inclusion of dielectric nanoparticles, a …

The anionic redox activity in lithium‐rich layered oxides has the potential to boost the energy density of lithium‐ion batteries. Although it is widely accepted that the anionic redox activity stems from the orphaned oxygen energy level, its regulation and structural stabilization, which are essential for practical employment, remain still elusive, requiring an improved fundamental understanding. Herein, the oxygen redox activity for a wide range of 3 d transition‐metal‐based Li 2 TMO 3 compounds is investigated and the intrinsic competition between the cationic and anionic redox reaction is unveiled. It is demonstrated that the energy level of the orphaned oxygen state (and, correspondingly, the activity) is delicately governed by the type and number of neighboring transition metals owing to the π‐type interactions between LiOLi and M t 2g states. Based on these findings, a simple model that can be used to estimate the …

The surface structure of solid catalysts has been regarded as a critical descriptor for determining the catalytic activities in various applications. However, structure-dependent catalytic activities have been rarely understood for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) within Li–O 2 batteries. Here, we succeeded in the preparation of a Pt catalyst with an anisotropic structure and demonstrated its high catalytic activity in nonaqueous Li–O 2 batteries. The cathode incorporating Pt exposed with high-index {411} facets showed greatly enhanced ORR and OER performance in comparison to commercial Pt/C cathode. The anisotropic Pt catalyst improved ORR activity with a large capacity of 12 985 mAh g carbon –1 , high rate performance, and stable cyclic retention up to 70 cycles with the capacity limited to 1000 mAh g carbon –1 . Furthermore, the anisotropic Pt catalyst exhibited high round …

Despite the exceptionally large theoretical energy density of lithium–oxygen batteries, their high charging overpotential and poor cycle life are critical limitations preventing their commercialization. To overcome these bottlenecks, redox mediators (i.e., soluble catalysts) that facilitate the electrochemical reaction between lithium and oxygen have attracted tremendous research interest. A wide variety of materials have been reported as promising redox mediators for lithium–oxygen batteries, successfully enhancing energy efficiency and cycle stability. However, their overall performance still requires further improvement. Herein, recent progress on the use of redox mediators for lithium–oxygen batteries are reviewed, with a particular focus on improvements in energy efficiency, power capability, and coulombic efficiency. In addition, the aspects of redox mediators requiring immediate optimization are discussed together …

O2-type lithium-rich layered oxides, known for mitigating irreversible transition metal migration and voltage decay, provide suitable framework for exploring the inherent properties of oxygen redox. Here, we present a series of O2-type lithium-rich layered oxides exhibiting minimal structural disordering and stable voltage retention even with high anionic redox participation based on the nominal composition. Notably, we observe a distinct asymmetric lattice breathing phenomenon within the layered framework driven by excessive oxygen redox, which includes substantial particle-level mechanical stress and the microcracks formation during cycling. This chemo-mechanical degradation can be effectively mitigated by balancing the anionic and cationic redox capabilities, securing both high discharge voltage (~ 3.43 V vs . Li/Li + ) and capacity (~ 200 mAh g −1 ) over extended cycles. The observed correlation between the …

Li–O 2 battery is one of the important next-generation energy storage systems, as it can potentially offer the highest theoretical energy density among battery chemistries reported thus far. However, realization of its high discharge capacity still remains challenging and is hampered by the nature of how the discharge products are formed, causing premature passivation of the air electrode. Redox mediators are exploited to solve this problem, as they can promote the charge transfer from electrodes to the solution phase. The mechanistic understanding of the fundamental electrochemical reaction involving the redox mediators would aid in the further development of Li–O 2 batteries along with rational design of new redox mediators. Herein, we attempt to monitor the discharge reaction of a Li–O 2 battery in real time by liquid-phase transmission electron microscopy (TEM). Direct in situ TEM observation reveals the gradual …

Governing the fundamental reaction in lithium–oxygen batteries is vital to realizing their potentially high energy density. Here, novel oxygen reduction reaction (ORR) catalysts capable of mediating the lithium and oxygen reaction within a solution‐driven discharge, which promotes the solution‐phase formation of lithium peroxide (Li 2 O 2 ), are reported, thus enhancing the discharge capacity. The new catalysts are derived from mimicking the biological redox mediation in the electron transport chain in Escherichia coli , where vitamin K2 mediates the oxidation of flavin mononucleotide and the reduction of cytochrome b in the cell membrane. The redox potential of vitamin K2 is demonstrated to coincide with the suitable ORR potential range of lithium–oxygen batteries in aprotic solvent, thereby enabling its successful functioning as a redox mediator (RM) triggering the solution‐based discharge. The use of vitamin K2 …

Advanced Materials for Energy Storage Lab

교수님 소개

박혁준

연구실 소개

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

[Invited] Decoding the Structural Controversy of Li- and Mn-Rich Cathodes Through Synthesis-Dependent Domain Evolution

Uniform pore structure enables negligible degradation in undoped and uncoated Ni-rich cathodes

Revitalizing multifunctionality of Li-Al-O system enabling mother-powder-free sintering of garnet-type solid electrolytes

연구실 보유 특허

대학별 입시끈

우리 연구실 모집

교수님 소개

박혁준

연구실 키워드

알럼나이가 간 회사

연구실 지원 방법

대우 조건

연도별 논문 인용수

저널 & 학회 논문 출판 수

연구실 논문 목록

[Invited] Decoding the Structural Controversy of Li- and Mn-Rich Cathodes Through Synthesis-Dependent Domain Evolution

Uniform pore structure enables negligible degradation in undoped and uncoated Ni-rich cathodes

Revitalizing multifunctionality of Li-Al-O system enabling mother-powder-free sintering of garnet-type solid electrolytes

연구실 보유 특허

최근 3년간 연구실적 높은 연구실

대학별 입시끈

우리 연구실 모집