Highly reversible Mg plating/stripping is key for rechargeable Mg batteries and has typically bee... more Highly reversible Mg plating/stripping is key for rechargeable Mg batteries and has typically been successfully demonstrated using transient electrochemical techniques such as cyclic voltammetry measurements. However, little effort has been invested in studying the stability of the electrode/electrolyte interface over an extended time. We report here the development of an in situ generated surface film for Mg anodes based on electrodeposited bismuth (E_Bi). This film improves the interfacial stability of Mg in contact with the electrolyte, particularly over an extended time, and possesses fast charge-transfer kinetics (<30 Ω∙cm2) and low non-time-sensitive interfacial film resistance (ca. 5 Ω∙cm2) for active Mg species.
Achieving a high energy density of lithium-ion batteries (LIBs) has been urgently required for fo... more Achieving a high energy density of lithium-ion batteries (LIBs) has been urgently required for forthcoming applications. Silicon anodes stand out as one of the promising candidates due to its high capacity and low working potential, while a structural failure from large expansion upon lithiation/delithiation poses a significant challenge [1]. The extensive efforts over the past has been devoted to addressing this issue by employing nanostructures, binder designs, and compositing methods. In this respect, we adopted multiple strategies, such as introducing multifunctional coating layers and separately realizing unique structures prepared via thermochemical reduction process of either inexpensive clay minerals or metal-organic-frameworks (MOFs), which demonstrate a great feasibility of their synthesis and electrochemical properties, thus satisfying a strict requirement for practical application (Figure 1). Multifunctional layers composed of lithium silicate (Li2SiO3) and lithium titan...
A salt-mediated, efficient and scalable extraction method enables the preparation of well-segrega... more A salt-mediated, efficient and scalable extraction method enables the preparation of well-segregated, high-quality, nanoscale silicon building blocks for the high-energy density lithium-ion full battery.
Three-dimensional porous Ge material has been fabricated via a thermal deformation of artificial ... more Three-dimensional porous Ge material has been fabricated via a thermal deformation of artificial Ge-rich zeolite, etching with warm water, and subsequent hydrogen reduction.
Lithium metal as a battery anode is the most promising energy storage materials owing to its high... more Lithium metal as a battery anode is the most promising energy storage materials owing to its high theoretical capacity and low working potential. However, uncontrollable Li growth during cycling raises...
Alloys are recently receiving considerable attention in the community of rechargeable batteries a... more Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of~50% at 20 C compared to that at 0.2 Crate) and cycle retention (73% at 3.0 Crate) with a retaining capacity of 546 mAh g −1 even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system.
Highly reversible Mg plating/stripping is key for rechargeable Mg batteries and has typically bee... more Highly reversible Mg plating/stripping is key for rechargeable Mg batteries and has typically been successfully demonstrated using transient electrochemical techniques such as cyclic voltammetry measurements. However, little effort has been invested in studying the stability of the electrode/electrolyte interface over an extended time. We report here the development of an in situ generated surface film for Mg anodes based on electrodeposited bismuth (E_Bi). This film improves the interfacial stability of Mg in contact with the electrolyte, particularly over an extended time, and possesses fast charge-transfer kinetics (<30 Ω∙cm2) and low non-time-sensitive interfacial film resistance (ca. 5 Ω∙cm2) for active Mg species.
Achieving a high energy density of lithium-ion batteries (LIBs) has been urgently required for fo... more Achieving a high energy density of lithium-ion batteries (LIBs) has been urgently required for forthcoming applications. Silicon anodes stand out as one of the promising candidates due to its high capacity and low working potential, while a structural failure from large expansion upon lithiation/delithiation poses a significant challenge [1]. The extensive efforts over the past has been devoted to addressing this issue by employing nanostructures, binder designs, and compositing methods. In this respect, we adopted multiple strategies, such as introducing multifunctional coating layers and separately realizing unique structures prepared via thermochemical reduction process of either inexpensive clay minerals or metal-organic-frameworks (MOFs), which demonstrate a great feasibility of their synthesis and electrochemical properties, thus satisfying a strict requirement for practical application (Figure 1). Multifunctional layers composed of lithium silicate (Li2SiO3) and lithium titan...
A salt-mediated, efficient and scalable extraction method enables the preparation of well-segrega... more A salt-mediated, efficient and scalable extraction method enables the preparation of well-segregated, high-quality, nanoscale silicon building blocks for the high-energy density lithium-ion full battery.
Three-dimensional porous Ge material has been fabricated via a thermal deformation of artificial ... more Three-dimensional porous Ge material has been fabricated via a thermal deformation of artificial Ge-rich zeolite, etching with warm water, and subsequent hydrogen reduction.
Lithium metal as a battery anode is the most promising energy storage materials owing to its high... more Lithium metal as a battery anode is the most promising energy storage materials owing to its high theoretical capacity and low working potential. However, uncontrollable Li growth during cycling raises...
Alloys are recently receiving considerable attention in the community of rechargeable batteries a... more Alloys are recently receiving considerable attention in the community of rechargeable batteries as possible alternatives to carbonaceous negative electrodes; however, challenges remain for the practical utilization of these materials. Herein, we report the synthesis of germanium-zinc alloy nanofibers through electrospinning and a subsequent calcination step. Evidenced by in situ transmission electron microscopy and electrochemical impedance spectroscopy characterizations, this one-dimensional design possesses unique structures. Both germanium and zinc atoms are homogenously distributed allowing for outstanding electronic conductivity and high available capacity for lithium storage. The as-prepared materials present high rate capability (capacity of~50% at 20 C compared to that at 0.2 Crate) and cycle retention (73% at 3.0 Crate) with a retaining capacity of 546 mAh g −1 even after 1000 cycles. When assembled in a full cell, high energy density can be maintained during 400 cycles, which indicates that the current material has the potential to be used in a large-scale energy storage system.
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Papers by Jaegeon Ryu