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Thermal stability of active electrode material in contact with solid electrolyte
TRON ARTUR,Nosenko Alexander,Mun Junyoung 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.2
For lithium battery systems including solid-state batteries, the solid electrolytes are playing an important role in enhancing the lithium transportation through the electrode/electrolyte interface resulting in the enhanced electrochemical performance of active materials which can prevent the dendrite formation for long term cycle life. However, the formation of the solid electrolyte fi lm on the materials' surface is carrying on via various types of methods. Especially for oxide-salt-type of solid electrolytes of Li 2 O–M x O y –Li x X y system, these solid electrolyte is forming on the surface of materials via the melt quench- ing technique at above 500 °C that can lead to the unstable and degradation the structure of the active materials resulting in the lower performance compared to the traditional (wet-chemistry or solid stare reaction) formation of solid electrolyte fi lm. In this work, the thermochemical stability of the active material in contact with the solid electrolyte after formation via a high-temperature method is investigated by the thermogravimetric and X-ray diff raction analysis, and galvanostatic charge– discharge and cyclic voltammetry measurements confi rm that the electrochemical degradation can be attributed mainly to the partial destruction of cathode structure and surface oxidation of current collector leading to the lower electrochemical performance. The results suggest that the process formation of solid electrolyte film of the oxide-salt system should not exceed 250–300 °C and is highly relevant to a critical area for the active electrode materials without the degradation of the material structure and decreasing electrochemical performance.
Tron, Artur,Kang, Hyunchul,Kim, Jinho,Mun, Junyoung The Korean Electrochemical Society 2018 Journal of electrochemical science and technology Vol.9 No.1
In aqueous rechargeable lithium ion batteries, $LiV_3O_8$ exhibits obviously enhanced electrochemical performance after $AlF_3$ surface modification owing to improved surface stability to fragile aqueous electrolyte. The cycle life of $LiV_3O_8$ is significantly enhanced by the presence of an $AlF_3$ coating at an optimal content of 1 wt.%. The results of powder X-ray diffraction, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma-optical emission spectrometry, and galvanostatic charge-discharge measurements confirm that the electrochemical improvement can be attributed mainly to the presence of $AlF_3$ on the surface of $LiV_3O_8$. Furthermore, the $AlF_3$ coating significantly reduces vanadium ion dissolution and surface failure by stabilizing the surface of the $LiV_3O_8$ in an aqueous electrolyte solution. The results suggest that the $AlF_3$ coating can prevent the formation of unfavorable side reaction components and facilitate lithium ion diffusion, leading to reduced surface resistance and improved surface stability compared to bare $LiV_3O_8$ and affording enhanced electrochemical performance in aqueous electrolyte solutions.
Tron, Artur,Yoon, Taeho,Park, Yeong Don,Oh, Seung M.,Mun, Junyoung American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.7
<P>Three types of NASICON-type ceramic materials which are Li1.3Al0.3Ti1.7(PO4)(3), Li1.3Sc0.15Y0.15 Ti-1.7(PO4)(3) and Li1.3Al0.3Zr1.7(PO4)(3) are prepared by a solid-state reaction for surface modification of LiCoO2 by mechano-chemical fusion coating. Ionic conductivity of the prepared ceramic electrolytes are evaluated as temperature changes, Li1.3Al0.3Ti1.7(PO4)(3), Li1.3Sc0.15Y0.15Ti1.7(PO4)(3) and Li1.3Al0.3Zr1.7(PO4)(3) exhibit the high ionic conductivity of 6.49x10(-4) S cm(-1), 5.61x10(-4) S cm(-1) and 4.85x10(-4) S cm(-1), respectively, at room temperature. Under the high cut-off potential for utilization large amount of lithium, the surface modification by ionic conducting coatings improves cycleability and rate capability of the lithium ion batteries. As ionic conductivity of coating materials increases, the coated LiCoO2 exhibits the better electrochemical performances. With AC impedance analyses, it is elucidated that the NASICON surface-coatings greatly relieve the interfacial resistance between LiCoO2 electrode and electrolyte.</P>
Tron, Artur,Mun, Junyoung The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.1
Owing to the rising concern of global warming, lithium-ion batteries have gained immense attention over the past few years for the development of highly efficient electrochemical energy conversion and storage systems. In this study, alpha-phase VOPO<sub>4</sub>·2H<sub>2</sub>O with nanosheet morphology was prepared via a facile hydrothermal method for application in high-performance lithium-ion batteries. The X-ray diffraction and scanning electron microscopy (SEM) analyses indicated that the obtained sample had an alpha-2 (αII) phase, and the nanosheet morphology of the sample was confirmed using SEM. The lithium-ion battery with VOPO<sub>4</sub>·2H<sub>2</sub>O as the anode exhibited excellent long-term cycle life and a high capacity of 256.7 mAh g<sup>-1</sup> at room temperature. Prelithiation effectively improved the specific capacity of pristine VOPO<sub>4</sub>·2H<sub>2</sub>O. The underlying electrochemical mechanisms were investigated by carrying out AC impedance, rate capability, and other instrumental analyses.
The solid electrolytes Li2O–LiF–Li2WO4–B2O3 with enhanced ionic conductivity for lithium-ion battery
Artur Tron,Alexander nosenko,박영돈,문준영 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.73 No.-
In this study, it is obtained solid electrolytes 60Li2O–10LiF–10Li2WO4–20B2O3 with content of LiF is10 mol% and Li2WO4 with 10 mol% exhibit high ionic conductivity of 1.7410 6 S cm 1 compared to thesolid electrolyte 50Li2O–20Li2WO4–30B2O3 without LiF is 2.510 7 S cm 1 at room temperature. Theobtained solid electrolyte is used as the surface agent of the active material LiCoO2 which displays cyclingstability and low electrode resistance via surface stabilization at a high potential of 4.4 V (vs. Li/Li+) at the1C current density for 100 cycles compared to the pristine material.