Publications by authors named "Hun-Gi Jung"

The demand for all-solid-state batteries (ASSBs) featuring credible LiPSCl argyrodite (LPSCl) electrolytes is increasing, driving interest in exploring suitable current collectors for ASSBs. Copper (Cu), used as a current collector in traditional lithium-ion batteries, exhibits significant instability in LPSCl-ASSBs. In this study, the effectiveness of iron (Fe) is systematically investigated as an alternative current collector in LPSCl-ASSBs and compare its performance to that of Cu.

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Construction of a robust artificial solid-electrolyte interphase (SEI) layer has proposed an effective strategy to overcome the instability of the lithium (Li). However, existing artificial SEI layers inadequately controlled ion distribution, leading to dendritic growth and penetration. Furthermore, the environmental impact of the manufacturing process and materials of the artificial layer is often overlooked.

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The O3-type Na[NiCoMn]O cathodes have received significant attention in sodium-ion batteries (SIBs) due to their high energy density. However, challenges such as structural instability and interfacial instability against an electrolyte solution limit their practical use in SIBs. In this study, the single-crystalline O3-type Na[NiCoMn]O (SC-NCM) cathode has been designed and synthesized to effectively relieve the degradation pathways of the polycrystalline O3-type Na[NiCoMn]O (PC-NCM) cathode for SIBs.

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This study explores the impact of introducing vacancy in the transition metal layer of rationally designed Na[NiRuMn]O (NRM) cathode material. The incorporation of Ru, Ni, and vacancy enhances the structural stability during extensive cycling, increases the operation voltage, and induces a capacity increase while also activating oxygen redox, respectively, in Na[NiVRuMn]O (V-NRM) compound. Various analytical techniques including transmission electron microscopy, X-ray absorption near edge spectroscopy, operando X-ray diffraction, and operando differential electrochemical mass spectrometry are employed to assess changes in the average oxidation states and structural distortions.

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Herein, an Au-coating layer adjusted on the surface of a Zn metal electrode that effectively suppresses the dendrite growth as well as the mechanisms underlying the dendrite suppression as a result of the zincophilic character of Au is introduced. For the Au-coated Zn metal symmetric cell, uniform deposition of Zn-derived compounds was revealed by operando synchrotron tomography. Microscopic studies demonstrate that the Au-coating layer is induced to form a new Zn-Au alloy during the initial Zn deposition, resulting in stabilized long-term stripping/plating of Zn via the 'embracing effect' that intimately accommodates Zn deposition for further cycles.

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Alloying-type metallic tin is perceived as a potential anode material for K-ion batteries owing to its high theoretical capacity and reasonable working potential. However, pure Sn still face intractable issues of inferior K storage capability owing to the mechanical degradation of electrode against large volume changes and formation of intermediary insulating phases K Sn and KSn during alloying reaction. Herein, the TiC/C-carbon nanotubes (CNTs) is prepared as an effective buffer matrix and composited with Sn particles (Sn-TiC/C-CNTs) through the high-energy ball-milling method.

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The incompatibility of lithium intercalation electrodes with water has impeded the development of aqueous Li-ion batteries. The key challenge is protons which are generated by water dissociation and deform the electrode structures through intercalation. Distinct from previous approaches utilizing large amounts of electrolyte salts or artificial solid-protective films, we developed liquid-phase protective layers on LiCoO (LCO) using a moderate concentration of 0.

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SiO is a promising next-generation anode material for lithium-ion batteries. However, its commercial adoption faces challenges such as low electrical conductivity, large volume expansion during cycling, and low initial Coulombic efficiency. Herein, to overcome these limitations, an eco-friendly in situ methodology for synthesizing carbon-containing mesoporous SiO nanoparticles wrapped in another carbon layers is developed.

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Lithium-oxygen batteries (LOBs) have attracted worldwide attention due to their high specific energy. However, the poor rechargeability and cycling stability of LOBs hinders their practical use in applications. Here, we explore the incomplete charging behavior of redox-mediated LOBs operated at a feasible capacity for a practical level (3.

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Sulfide-based inorganic solid electrolytes have been considered promising candidates for all-solid-state batteries owing to their high ionic conductivity. Compared with oxide-based inorganic solid electrolytes which require high-temperature sintering, the intrinsic deformability of sulfide electrolytes enables the fabrication of all-solid-state batteries by a simple cold pressing method. Nevertheless, the performance of sulfide-based all-solid-state batteries is still unsatisfactory, owing to the insufficient interfacial properties within the composite electrodes.

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Promising high-capacity anodes of Si-based materials suffer from large volume expansions, thereby limiting their practical applications, especially in combination with safe inorganic solid electrolytes. Here, to achieve a high level of safety by applying Si anodes, we introduced a quasi-solid-state succinonitrile-based electrolyte (QS-SCN) that enables the practical application of the anode with long-term cycling performance. By exploiting the unique phase-convertible property of QS-SCN, the Si electrode was successfully impregnated with the liquid-state electrolyte above its melting temperature, and a simple cooling process was then used to form a quasi-solid-state Li-Si cell.

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Metal-sulfur batteries (MSBs) provide high specific capacity due to the reversible redox mechanism based on conversion reaction that makes this battery a more promising candidate for next-generation energy storage systems. Recently, along with elemental sulfur (S ), sulfurized polyacrylonitrile (SPAN), in which active sulfur moieties are covalently bounded to carbon backbone, has received significant attention as an electrode material. Importantly, SPAN can serve as a universal cathode with minimized metal-polysulfide dissolution because sulfur is immobilized through covalent bonding at the carbon backbone.

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The growing demand for green energy has fueled the exploration of sustainable and eco-friendly energy storage systems. To date, the primary focus has been solely on the enhancement of lithium-ion battery (LIB) technologies. Recently, the increasing demand and uneven distribution of lithium resources have prompted extensive attention toward the development of other advanced battery systems.

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Sulfide solid electrolytes (SEs) with high Li-ion conductivities (σ) and soft mechanical properties have limited applications in wet casting processes for commercial all-solid-state batteries (ASSBs) because of their inherent atmospheric and chemical instabilities. In this study, we fabricated sulfide SEs with a novel core-shell structure via environmental mechanical alloying, while providing sufficient control of the partial pressure of oxygen. This powder possesses notable atmospheric stability and chemical resistance because it is covered with a stable oxysulfide nanolayer that prevents deterioration of the bulk region.

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The development of solid electrolytes (SEs) is a promising pathway to improve the energy density and safety of conventional Li-ion batteries. Several lithium chloride SEs, LiMCl (M = Y, Er, In, and Sc), have gained popularity due to their high ionic conductivity, wide electrochemical window, and good chemical stability. This study systematically investigated 17 LiMCl SEs to identify novel and promising lithium chloride SEs.

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Although several crystalline materials have been developed as Li-ion conductors for use as solid electrolytes in all-solid-state batteries (ASSBs), producing materials with high Li-ion conductivities is time-consuming and cost-intensive. Herein, we introduce a superionic halogen-rich Li-argyrodite (HRLA) and demonstrate its innovative synthesis using ultimate-energy mechanical alloying (UMA) and rapid thermal annealing (RTA). UMA with a 49 G-force milling energy provides a one-pot process that includes mixing, glassification, and crystallization, to produce as-milled HRLA powder that is ∼70% crystallized; subsequent RTA using an infrared lamp increases this crystallinity to ∼82% within 25 min.

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Silicon has a great potential as an alternative to graphite which is currently used commercially as an anode material in lithium-ion batteries (LIBs) because of its exceptional capacity and reasonable working potential. Herein, a low-cost and scalable approach is proposed for the production of high-performance silicon-carbon (Si-C) hybrid composite anodes for high-energy LIBs. The Si-C composite material is synthesized using a scalable microemulsion method by selecting silicon nanoparticles, using low-cost corn starch as a biomass precursor and finally conducting heat treatment under CH gas.

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Most active materials for sodium-ion batteries suffer from the problem of low-energy efficiency in the first cycle because of the loss of active sodium ions consumed for the formation of a solid electrolyte interface. To make up for the lost sodium ion, presodiation treatments have been applied, which are effective ways to mitigate the low initial efficiency. Here, we developed a direct-contact method to achieve the presodiation for cathode and anode electrodes and demonstrated the enhanced Coulombic efficiency of the first cycle with improved cyclability and reversible capacity.

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Non-aqueous lithium-oxygen batteries cycle by forming lithium peroxide during discharge and oxidizing it during recharge. The significant problem of oxidizing the solid insulating lithium peroxide can greatly be facilitated by incorporating redox mediators that shuttle electron-holes between the porous substrate and lithium peroxide. Redox mediator stability is thus key for energy efficiency, reversibility, and cycle life.

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Sodium-ion batteries are considered the most promising power source for electrical energy storage systems because of the abundance of sodium and their significant cost advantages. However, high-performance electrode materials are required for their successful application. Herein, we report a monoclinic-type CoMoO material which is synthesized by a simple solution method.

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We determined the interatomic potentials of the Li-[PS] building block in (LiS)(PS) (LPS) and predicted the Li-ion conductivity (σ) of glass-ceramic LPS from molecular dynamics. The Li-ion conduction characteristics in the crystalline/interfacial/glassy structure were decomposed by considering the structural ordering differences. The superior σ of the glassy LPS could be attributed to the fact that ∼40% of its structure consists of the short-ranged cubic S-sublattice instead of the hexagonally close-packed γ-phase.

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The interest in the development of micro-nanostructured metal oxides has been increasing recently because of their advantages as electrode materials in energy storage applications. In this study, dandelion-like ZnxCo3-xO4 microspheres assembled with porous needle-shaped nanosticks were synthesized by co-precipitation followed by a post-annealing treatment. The open space between neighboring nanosticks enables easy infiltration of the electrolyte; therefore, each nanostick is surrounded by the electrolyte solution, which ensures proper utilization of the active material during the electrochemical reaction.

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The composite cathode of an all-solid-state battery composed of various solid-state components requires a dense microstructure and a highly percolated solid-state interface different from that of a conventional liquid-electrolyte-based Li-ion battery. Indeed, the preparation of such a system is particularly challenging. In this study, quantitative analyses of composite cathodes by three-dimensional reconstruction analysis were performed beyond the existing qualitative analysis, and their microstructures and reaction interfaces were successfully analyzed.

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Boosting the performance of rechargeable lithium-ion batteries (LIBs) beyond the state-of-the-art is mandatory toward meeting the future energy requirements of the consumer mass market. The replacement of conventional graphite anodes with conversion-type metal-oxide anodes is one progressive approach toward achieving this goal. Here, a LIB consisting of a highcapacity spinel NiMn O anode and a high-voltage spinel LiNi Mn O cathode was proposed.

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