Surface Modification of LiCoO₂ by NASICON-Type Ceramic Materials for Lithium Ion Batteries

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>

Electrochemical Performance of AlF₃-Coated LiV₃O₈ for Aqueous Rechargeable Lithium Ion Batteries

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.

Retraction Note: Prelithiation of Alpha Phase Nanosheet-Type VOPO₄·2H₂O Anode for Lithium-Ion Batteries

Tron, Artur,Mun, Junyoung The Korean Electrochemical Society 2022 Journal of electrochemical science and technology Vol.13 No.2

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.

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.

Prelithiation of Alpha Phase Nanosheet-Type VOPO₄·2H₂O Anode for Lithium-Ion Batteries

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 VOPO₄·2H₂O 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 VOPO₄·2H₂O as the anode exhibited excellent long-term cycle life and a high capacity of 256.7 mAh g^-1 at room temperature. Prelithiation effectively improved the specific capacity of pristine VOPO₄·2H₂O. The underlying electrochemical mechanisms were investigated by carrying out AC impedance, rate capability, and other instrumental analyses.

Surface Modification for Aqueous Rechargeable Battery System

문준영,( Artur Tron ) 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Batteries have been expanded to large facilities, however, using organic electrolytes which are dangerous, and expensive, restrict their applications. One of prospective rechargeable battery is the aqueous rechargeable battery (ARB), with aqueous electrolyte instead of organic electrolyte. However, it has not been considered for power sources of practical applications owing to poor performances of the aqueous electrolyte. We have focused on ARBs for Na/Li ions by surface modification. The physicochemical and electrochemical properties of surface modification of cathode were investigated by XRD, SEM, EDS, XPS and electrochemical methods. This result demonstrates that the surface coating of cathode improves the performance. Based on these, we suggest that the surface modification of the electrode materials performs an important role in improvement of the performances of the ARBs. ** This work was supported by the National Research Foundation of Korea (NRF-2018R1D1A1B07048144).

Adsorptive Li+ mining from liquid resources by H2TiO3: Equilibrium, kinetics, thermodynamics, and mechanisms

Chosel P. Lawagon,Grace M. Nisola,문준영,Artur Tron,레이토레호스,서정길,김헌,정욱진 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.35 No.-

Metatitanic acid (H2TiO3) is an emerging lithium ion sieve (LIS) that can potentially replace the well-known manganese-based LIS. Systematic adsorption studies on the effects of solution pH, solid/liquidratio, temperature, and feed concentration were conducted. H+ accumulation critically limited the Li+capacity (qe), but was circumvented under optimal conditions. Li+ adsorption was Langmuir-type andfollowed pseudo-second-order rate model; thermodynamic parameters reveal its feasibility, spontanei-ty, and endothermicity. H2TiO3 was highly stable and reusable; its highest qe (94.5 mg g 1) is superiorover other known LIS. Li+ was effectively recovered from seawater, demonstrating its high industrialpotential for aqueous Li+ mining.

Physically cross-linked polymer binder based on poly(acrylic acid) and ion-conducting poly(ethylene glycol-<i>co</i>-benzimidazole) for silicon anodes

Lim, Sanghyun,Lee, Kukjoo,Shin, Inseop,Tron, Artur,Mun, Junyoung,Yim, Taeeun,Kim, Tae-Hyun Elsevier Sequoia 2017 Journal of Power Sources Vol. No.

<P><B>Abstract</B></P> <P>The practical applications of Si electrodes in lithium-ion batteries are limited since they undergo large changes in volume during charge and discharge, and consequently become highly deteriorated. A novel binder system holding silicon particles together and preventing disintegration of the electrode during operation hence needs to be developed to enable reliable cycleability. In the current work, such a new polymer binder system, based on poly(acrylic acid) (PAA) and poly(ethylene glycol-<I>co</I>-benzimidazole) (PEGPBI), is developed for silicon anodes. The physical crosslinking using acid-base interactions between PAA and PBI, together with the ion-conducting PEG group, yields physical properties for the resulting PAA-PEGPBI-based anodes that are better than those of electrodes based on the currently available PAA binder, and yields good cell performances. A Si-based electrode with high loading levels of 1.0–1.3 mg cm<SUP>−2</SUP> (0.7–0.91 Si mg cm<SUP>−2</SUP>) is reliably manufactured using specifically PAA-PEGPBI-2, which is made with 2 wt% of PEGPBI relative to PAA, and shows a very high capacity value of 1221 mAh g<SUP>−1</SUP> at a rate of 0.5 C after 50 cycles, and a high capacity value of more than 1600 mAh g<SUP>−1</SUP> at a high rate of 2 C.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Physically-crosslinked polymer binders are developed for Si anode. </LI> <LI> Physical and electrochemical properties of new binders are investigated. </LI> <LI> Reversible acid-base interaction and ion conductivity are provided to new binders. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

고전압 리튬이차전지를 위한 LiNi_0.5Mn_1.5O₄ 양극용 전해질로써 상온 이온성 액체 전해질의 불순물 효과에 관한 연구

김지용,임태은,문준영,Kim, Jiyong,Tron, Artur V.,Yim, Taeeun,Mun, Junyoung 한국전기화학회 2015 한국전기화학회지 Vol.18 No.2

상온 이온성 액체인 propylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMPyr-TFSI)를 리튬이차전지 전해질 용매로 사용 시 PMPyr-TFSI 내 수분 및 브롬 불순물이 전지의 성능에 미치는 영향을 연구하였다. 고전압 양극 물질인 $LiNi_{0.5}Mn_{1.5}O_4$ 스피넬 구조 양극을 이용한 반쪽 전지의 전해질로 PMPyr-TFSI를 사용 하는데 있어, PMPyr-TFSI의 수분 함유량을 각각 12, 77, 1060 ppm으로 제어하고 전압 곡선 개형 및 쿨롱 효율 거동 추적을 통해 PMPyr-TFSI 수분량이 전지 성능에 부정적인 영향을 미치는 것을 구체적으로 확인하였다. 또한, PMPyr-TFSI 전해질 내의 브롬 이온 불순물 양 제어를 통하여, 전지 내에서 브롬 이온 불순물과 관련한 전기화학 부반응을 찾아 내었다. 이들 할로겐 불순물에 의한 초기 전지 쿨롱 효율저하는 눈에 띠었으나, 수명 저하에는 큰 변화가 없음을 확인하였다. We report the effect of the impurities including water and bromide in the propylmethylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PMPyr-TFSI) on the electrochemical performance of lithium ion batteries. The several kinds of PMPyr-TFSI electrolytes with different amount of impurities are applied as the electrolyte to the cell with the high potential electrode, $LiNi_{0.5}Mn_{1.5}O_4$ spinel. It is found that the impurities in the electrolytes cause the detrimental effect on the cell performance by tracing the cycleability, voltage profile and Coulombic efficiency. Especially, the polarization and Coulombic efficiency go to worse by both impurities of water and bromide, but the cycleability was not highly influenced by bromide impurity unlike the water impurity.