Publications by authors named "Yang Kook Sun"

LiNiCoAlO (NCA95) is charged up to 4.6 V to study its structural stability at a highly delithiated state using transmission electron microscopy (TEM). The TEM analysis shows that the localized depletion of Li ions near the surface triggers the transition from the H3 phase to the H4 phase with the H4 phase with the O1 stacking appearing as a series of stacking faults even at 4.

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Lithium transition metal oxide layers, Li[NiCo(Mn and/or Al)]O, are widely used and mass-produced for current rechargeable battery cathodes. Development of cathode materials has focused on increasing the Ni content by simply controlling the chemical composition, but as the Ni content has almost reached its limit, a new breakthrough is required. In this regard, microstructural modification is rapidly emerging as a prospective approach, namely in the production of nano-rod layered cathode materials.

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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 paper delves into the critical materials supply chain of the battery market with an emphasis on long-term energy security. The study recognizes electric vehicle battery packs as reservoirs of "locked reserves" for extended periods, typically 10 years or more. A comprehensive understanding of material flows and end-of-life battery management is essential to establish a sustainable, durable, and secure domestic supply chain for lithium-ion batteries.

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Article Synopsis
  • All-solid-state lithium-sulfur batteries (ASSLSBs) are promising due to their high energy density, low cost, improved safety, and elimination of polysulfide dissolution, but they face challenges with sulfur's insulating properties.
  • The researchers developed a flower-shaped composite of MoS nanoparticles and sulfur to enhance ionic and electrical conduction in the battery's cathode, overcoming issues with MoS becoming isolated by surrounding sulfur.
  • The resulting MoS/sulfur composite, created through mild milling and melt diffusion, showed impressive performance in a lithium sulfide solid electrolyte-based ASSLSB, maintaining stable operation over 1000 cycles with nearly 100% efficiency, highlighting the importance of material design for battery performance.
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Fast charging technology for electric vehicles (EVs), offering rapid charging times similar to conventional vehicle refueling, holds promise but faces obstacles owing to kinetic issues within lithium-ion batteries (LIBs). Specifically, the significance of cathode materials in fast charging has grown because Ni-rich cathodes are employed to enhance the energy density of LIBs. Herein, the mechanism behind the loss of fast charging capability of Ni-rich cathodes during extended cycling is investigated through a comparative analysis of Ni-rich cathodes with different microstructures.

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Deploying Ni-enriched (Ni≥95 %) layered cathodes for high energy-density lithium-ion batteries (LIBs) requires resolving a series of technical challenges. Among them, the structural weaknesses of the cathode, vigorous reactivity of the labile Ni ion species, gas evolution and associated cell swelling, and thermal instability issues are critical obstacles that must be solved. Herein, we propose an intuitive strategy that can effectively ameliorate the degradation of an extremely high-Ni-layered cathode, the construction of ultrafine-scale microstructure and subsequent intergranular shielding of grains.

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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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Lithium-sulfur (Li-S) batteries using LiS and Li-free anodes have emerged as a potential high-energy and safe battery technology. Although the operation of Li-S full batteries based on LiS has been demonstrated at room temperature, their effective use at a subzero temperature has not been realized due to the low electrochemical utilization of LiS. Here, ammonium nitrate (NHNO) is introduced as a functional additive that allows Li-S full batteries to operate at -10 °C.

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Batteries using potassium metal (K-metal) anode are considered a new type of low-cost and high-energy storage device. However, the thermodynamic instability of the K-metal anode in organic electrolyte solutions causes uncontrolled dendritic growth and parasitic reactions, leading to rapid capacity loss and low Coulombic efficiency of K-metal batteries. Herein, an advanced electrolyte comprising 1 M potassium bis(fluorosulfonyl)imide (KFSI) + 0.

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Electrolyte design has become ever more important to enhance the performance of lithium-ion batteries (LIBs). However, the flammability issue and high reactivity of the conventional electrolytes remain a major problem, especially when the LIBs are operated at high voltage and extreme temperatures. Herein, we design a novel non-flammable fluorinated ester electrolyte that enables high cycling stability in wide-temperature variations (e.

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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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The exploitation of effective strategies to accelerate the Na diffusion kinetics and improve the structural stability in the electrode is extremely important for the development of high efficientcy sodium-ion batteries. Herein, Se vacancies and heterostructure engineering are utilized to improve the Na -storage performance of transition metal selenides anode prepared through a facile two-in-one route. The experimental results coupled with theoretical calculations reveal that the successful construction of the Se vacancies and heterostructure interfaces can effectively lower the Na diffusion barrier, accelerate the charge transfer efficiency, improve Na adsorption ability, and provide an abundance of active sites.

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Boron (B) (1.5 mol %) is introduced into Li[NiCoAl]O (NCA95) to create a radially oriented microstructure with a strong crystallographic texture. The cathode microstructure allows dissipation of the abrupt lattice strain near the charge end and improves the cycling stability of the NCA95 cathode (88% capacity retention after 100 cycles at 0.

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Doping is a well-known strategy to enhance the electrochemical energy storage performance of layered cathode materials. Many studies on various dopants have been reported; however, a general relationship between the dopants and their effect on the stability of the positive electrode upon prolonged cell cycling has yet to be established. Here, we explore the impact of the oxidation states of various dopants (i.

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High-voltage lithium-ion batteries (LIBs) enabled by high-voltage electrolytes can effectively boost energy density and power density, which are critical requirements to achieve long travel distances, fast-charging, and reliable safety performance for electric vehicles. However, operating these batteries beyond the typical conditions of LIBs (4.3 V vs Li/Li ) leads to severe electrolyte decomposition, while interfacial side reactions remain elusive.

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To realize lithium-sulfur (Li-S) batteries with high energy density, it is crucial to maximize the loading level of sulfur cathode and minimize the electrolyte content. However, excessive amounts of lithium polysulfides (LiPSs) generated during the cycling limit the stable operation of Li-S batteries. In this study, a high-loading S cathode with a three-dimensional (3D) network structure is fabricated using a simple pelletizing method, and the exhausting overcharging phenomenon, which occurs in the high-loading Li-S cell, is successively prevented by pretreating the lithium metal anode.

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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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Materials in nature have evolved to the most efficient forms and have adapted to various environmental conditions over tens of thousands of years. Because of their versatile functionalities and environmental friendliness, numerous attempts have been made to use bio-inspired materials for industrial applications, establishing the importance of biomimetics. Biomimetics have become pivotal to the search for technological breakthroughs in the area of rechargeable secondary batteries.

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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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Lithium dendrite-free deposition is crucial to stabilizing lithium batteries, where the three-dimensional (3D) metal oxide nanoarrays demonstrate an impressive capability to suppress dendrite due to the spatial effect. Herein, we introduce a new insight into the ameliorated lithium plating process on 3D nanoarrays. As a paradigm, novel 3D CuO and Cu nanorod arrays were designed on copper foil.

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Lithium-sulfur (Li-S) batteries are considered one of the most promising energy storage technologies, possibly replacing the state-of-the-art lithium-ion (Li-ion) batteries owing to their high energy density, low cost, and eco-compatibility. However, the migration of high-order lithium polysulfides (LiPs) to the lithium surface and the sluggish electrochemical kinetics pose challenges to their commercialization. The interactions between the cathode and LiPs can be enhanced by the doping of the carbon host with heteroatoms, however with relatively low doping content (<10%) in the bulk of the carbon, which can hardly interact with LiPs at the host surface.

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Manganese (Mn)-based cathode materials have garnered huge research interest for rechargeable aqueous zinc-ion batteries (AZIBs) due to the abundance and low cost of manganese and the plentiful advantages of manganese oxides including their different structures, wide range of phases, and various stoichiometries. A novel in situ generated Mn-deficient ZnMnO@C (Mn-d-ZMO@C) nanoarchitecture cathode material from self-assembly of ZnO-MnO@C for rechargeable AZIBs is reported. Analytical techniques confirm the porous and crystalline structure of ZnO-MnO@C and the in situ growth of Mn deficient ZnMnO@C.

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Alloying anodes exhibit very high capacity when used in potassium-ion batteries, but their severe capacity fading hinders their practical applications. The failure mechanism has traditionally been attributed to the large volumetric change and/or their fragile solid electrolyte interphase. Herein, it is reported that an antimony (Sb) alloying anode, even in bulk form, can be stabilized readily by electrolyte engineering.

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We developed a new nanowire for enhancing the performance of lithium-sulfur batteries. In this study, we synthesized WO nanowires (WNWs) via a simple hydrothermal method. WNWs and one-dimensional materials are easily mixed with carbon nanotubes (CNTs) to form interlayers.

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