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

Li–O2 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–O2 batteries along with rational design of new redox mediators. Herein, we attempt to monitor the discharge reaction of a Li–O2 battery in real time by liquid-phase transmission electron microscopy (TEM). Direct in situ TEM observation reveals the gradual growth of toroidal Li2O2 discharge product in the electrolyte with the redox mediator upon discharge. Moreover, quantitative analyses of the growth profiles elucidate that the growth mechanism involves two steps: dominant lateral growth of Li2O2 into disclike structures in the early stage followed by vertical growth with morphology transformation into a toroidal structure

Facile Preparation of Magnetite-Incorporated Polyacrylonitrile-Derived Carbons for Li-Ion Battery Anodes

A facile preparation method for magnetite (Fe3O4)-incorporated polyacrylonitrile (PAN)-derived carbon composites was developed to overcome the limitations of graphite-based materials for Li-ion batteries (LIBs), and the electrochemical performance of this material as an anode for LIBs was investigated. In this study, Fe3O4 nanoparticles (NPs) with hydrophobic surfaces and graphitizable hydrophobic PAN formed through radical polymerization were uniformly distributed in an emulsion system, and subsequently, a partially graphitic carbon composite containing Fe3O4 NPs was obtained through simple oxidation and carbonization processes. The presence of Fe3O4 NPs contributed to a slight increase in the graphitization efficiency of PAN, as well as the additional uptake of lithium ions in LIBs. As a result, when the developed composite was applied as an anode for LIBs, they exhibited increased specific capacities and stable cycle performance over more than 100 cycles. In particular, it was confirmed that the rate capability of the composite was significantly higher than that of commercial graphite. The results indicate that the developed composite is promising for applications in advanced LIBs that are specialized for high-power devices

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

Li–O2 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–O2 batteries along with rational design of new redox mediators. Herein, we attempt to monitor the discharge reaction of a Li–O2 battery in real time by liquid-phase transmission electron microscopy (TEM). Direct in situ TEM observation reveals the gradual growth of toroidal Li2O2 discharge product in the electrolyte with the redox mediator upon discharge. Moreover, quantitative analyses of the growth profiles elucidate that the growth mechanism involves two steps: dominant lateral growth of Li2O2 into disclike structures in the early stage followed by vertical growth with morphology transformation into a toroidal structure

sj-pdf-1-roa-10.1177_01640275211065441 – Supplemental Material for The Effects of Charitable Giving on Life Satisfaction of Older Korean Adults: The Moderating Role of Relationship Satisfaction and Social Trust

Supplemental Material, sj-pdf-1-roa-10.1177_01640275211065441 for The Effects of Charitable Giving on Life Satisfaction of Older Korean Adults: The Moderating Role of Relationship Satisfaction and Social Trust by Hey Jung Jun, Miseon Kang, Do Kyung Yoon, Seol Ah Lee and Hayoung Park in Research on Aging</p

Early Stage Li Plating by Liquid Phase and Cryogenic Transmission Electron Microscopy

Li metal anodes are among the most promising options for next-generation batteries, exhibiting the highest theoretical capacity. However, irregular Li electrodeposition, which raises safety concerns, is a major obstacle in practical applications. Therefore, a fundamental understanding of the beginning phases of Li plating, such as nucleation and early growth, which have a decisive influence on the dendritic growth of Li, is essential. In this study, we investigated the early stage of Li plating at the single-particle level and its correlation with the solid-electrolyte interphase (SEI) using in situ liquid phase transmission electron microscopy (TEM) and cryogenic TEM. We observed contrasting nucleation dynamics and particle growth patterns in two electrolytes (1 M LiPF6 in ethylene carbonate/diethyl carbonate and 1 M LiTFSI in 1,3-dioxolane/dimethoxy ethane), which originate from different chemical and physical properties of the SEIs. Based on our findings, we propose a mechanism of nucleation and initial growth of Li dictated by the SEI

Early Stage Li Plating by Liquid Phase and Cryogenic Transmission Electron Microscopy

Li metal anodes are among the most promising options for next-generation batteries, exhibiting the highest theoretical capacity. However, irregular Li electrodeposition, which raises safety concerns, is a major obstacle in practical applications. Therefore, a fundamental understanding of the beginning phases of Li plating, such as nucleation and early growth, which have a decisive influence on the dendritic growth of Li, is essential. In this study, we investigated the early stage of Li plating at the single-particle level and its correlation with the solid-electrolyte interphase (SEI) using in situ liquid phase transmission electron microscopy (TEM) and cryogenic TEM. We observed contrasting nucleation dynamics and particle growth patterns in two electrolytes (1 M LiPF6 in ethylene carbonate/diethyl carbonate and 1 M LiTFSI in 1,3-dioxolane/dimethoxy ethane), which originate from different chemical and physical properties of the SEIs. Based on our findings, we propose a mechanism of nucleation and initial growth of Li dictated by the SEI

Early Stage Li Plating by Liquid Phase and Cryogenic Transmission Electron Microscopy

Li metal anodes are among the most promising options for next-generation batteries, exhibiting the highest theoretical capacity. However, irregular Li electrodeposition, which raises safety concerns, is a major obstacle in practical applications. Therefore, a fundamental understanding of the beginning phases of Li plating, such as nucleation and early growth, which have a decisive influence on the dendritic growth of Li, is essential. In this study, we investigated the early stage of Li plating at the single-particle level and its correlation with the solid-electrolyte interphase (SEI) using in situ liquid phase transmission electron microscopy (TEM) and cryogenic TEM. We observed contrasting nucleation dynamics and particle growth patterns in two electrolytes (1 M LiPF6 in ethylene carbonate/diethyl carbonate and 1 M LiTFSI in 1,3-dioxolane/dimethoxy ethane), which originate from different chemical and physical properties of the SEIs. Based on our findings, we propose a mechanism of nucleation and initial growth of Li dictated by the SEI

Additive-Driven Nanoscale Architecture of Solid Electrolyte Interphase Revealed by Cryogenic Transmission Electron Microscopy

In Li metal batteries (LMBs), which boast the highest theoretical capacity, the chemical structure of the solid electrolyte interphase (SEI) serves as the key component that governs the growth of reactive Li. Various types of additives have been developed for electrolyte optimization, representing one of the most effective strategies to enhance the SEI properties for stable Li plating. However, as advanced electrolyte systems become more chemically complicated, the use of additives is empirically optimized. Indeed, their role in SEI formation and the resulting cycle life of LMBs are not well-understood. In this study, we employed cryogenic transmission electron microscopy combined with Raman spectroscopy, theoretical studies including molecular dynamics (MD) simulations and density functional theory (DFT) calculations, and electrochemical measurements to explore the nanoscale architecture of SEI modified by the most representative additives, lithium nitrate (LiNO3) and vinylene carbonate (VC), applied in a localized high-concentration electrolyte. We found that LiNO3 and VC play distinct roles in forming the SEI, governing the solvation structure, and influencing the kinetics of electrochemical reduction. Their collaboration leads to the desired SEI, ensuring prolonged cycle performance for LMBs. Moreover, we propose mechanisms for different Li growth and cycling behaviors that are determined by the physicochemical properties of SEI, such as uniformity, elasticity, and ionic conductivity. Our findings provide critical insights into the appropriate use of additives, particularly regarding their chemical compatibility