Chemical aspect of oxygen dissolved in a dimethyl sulfoxide-based electrolyte on lithium metal

Lee, Hongkyung,Lee, Dong Jin,Lee, Je-Nam,Song, Jongchan,Lee, Yunju,Ryou, Myung-Hyun,Park, Jung-Ki,Lee, Yong Min Elsevier 2014 ELECTROCHIMICA ACTA Vol.123 No.-

Electrospun Three-Dimensional Mesoporous Silicon Nanofibers as an Anode Material for High-Performance Lithium Secondary Batteries

Lee, Dong Jin,Lee, Hongkyung,Ryou, Myung-Hyun,Han, Gi-Beom,Lee, Je-Nam,Song, Jongchan,Choi, Jaecheol,Cho, Kuk Young,Lee, Yong Min,Park, Jung-Ki American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.22

<P>Mesoporous silicon nanofibers (m-SiNFs) have been fabricated using a simple and scalable method via electrospinning and reduction with magnesium. The prepared m-SiNFs have a unique structure in which clusters of the primary Si nanoparticles interconnect to form a secondary three-dimensional mesoporous structure. Although only a few nanosized primary Si particles lead to faster electronic and Li<SUP>+</SUP> ion diffusion compared to tens of nanosized Si, the secondary nanofiber structure (a few micrometers in length) results in the uniform distribution of the nanoparticles, allowing for the easy fabrication of electrodes. Moreover, these m-SiNFs exhibit impressive electrochemical characteristics when used as the anode materials in lithium ion batteries (LIBs). These include a high reversible capacity of 2846.7 mAh g<SUP>–1</SUP> at a current density of 0.1 A g<SUP>–1</SUP>, a stable capacity retention of 89.4% at a 1 C rate (2 A g<SUP>–1</SUP>) for 100 cycles, and a rate capability of 1214.0 mAh g<SUP>–1</SUP> (at 18 C rate for a discharge time of ∼3 min).</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2013/aamick.2013.5.issue-22/am403798a/production/images/medium/am-2013-03798a_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am403798a'>ACS Electronic Supporting Info</A></P>

Polysulfide rejection layer from alpha-lipoic acid for high performance lithium-sulfur battery

Song, Jongchan,Noh, Hyungjun,Lee, Hongkyung,Lee, Je-Nam,Lee, Dong Jin,Lee, Yunju,Kim, Chul Hwan,Lee, Yong Min,Park, Jung-Ki,Kim, Hee-Tak The Royal Society of Chemistry 2015 Journal of Materials Chemistry A Vol.3 No.1

<P>The polysulfide shuttle has been an impediment to the development of lithium-sulfur batteries with high capacity and cycling stability. Here, we report a new strategy to remedy the problem that uses alpha-lipoic acid (ALA) as an electrolyte additive to form a polysulfide rejection layer on the cathode surface<I>via</I>the electrochemical and chemical polymerization of ALA and a stable solid electrolyte interface (SEI) layer on the Li metal anode during the first discharge. The poly(ALA) layer formed<I>in situ</I>effectively prevents the polysulfide shuttle and consequently enhances the discharge capacity and cycling stability, owing to the Donnan potential developed between the polysulfide-concentrated cathode and the fixed negative charge-concentrated poly(ALA) layer. Also, the SEI layer additionally prevents the chemical reaction of the polysulfide and Li metal anode. The approach, based on the double effect, encompasses a new scientific strategy and provides a practical methodology for high performance lithium-sulfur batteries.</P>

고성능 리튬 설퍼 전지 구현을 위한 폴리설파이드 억제막

( Hee-tak Kim ),( Jongchan Song ),( Hyungjun Noh ),( Hongkyung Lee ),( Je-nam Lee ),( Dong Jin Lee ),( Yunju Lee ),( Chul Hwan Kim ),( Yong Min Lee ),( Jung-ki Park ) 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1

The polysulfide shuttle has been an impediment to the development of lithium-sulfur batteries with high capacity and cycling stability. Here, we report a new strategy to remedy the problem that uses alpha-lipoic acid (ALA), as an electrolyte additive to form a polysulfide rejection layer on the cathode surface via the electrochemical and chemical polymerization of ALA during the first discharge. The poly(ALA) layer formed in situ effectively prevents the polysulfide shuttle and consequently enhances the discharge capacity and cycling stability, owing to the Donnan potential developed between the polysulfide-concentrated cathode and the fixed negative charge-concentrated poly(ALA) layer. The approach, based on a thermodynamic equilibrium and a natural material, encompasses a new scientific strategy and provides a practical methodology for high performance lithium-sulfur batteries.

A simple composite protective layer coating that enhances the cycling stability of lithium metal batteries

Lee, Hongkyung,Lee, Dong Jin,Kim, Yun-Jung,Park, Jung-Ki,Kim, Hee-Tak Elsevier 2015 Journal of Power Sources Vol.284 No.-

<P><B>Abstract</B></P> <P>Metallic lithium is the most promising negative electrode for high-energy rechargeable batteries due to its extremely high specific capacity and its extremely low redox potential. However, the low cycle efficiency and lithium dendrite formation during the charge/discharge processes consistently hinder its practical application. In this report, we present a stabilized Li electrode on which a Li<SUP>+</SUP> ion conductive inorganic/organic composite protective layer (CPL) is coated. With the introduction of the CPL, the Li dendrite growth and electrolyte decomposition are effectively suppressed; consequently, stable Li plating/stripping at high current densities up to 10 mA cm<SUP>−2</SUP> is possible. Nanoindentation tests demonstrate that the shear modulus of the CPL at narrow indentations is 1.8 times higher than that of the Li metal, which provides a theoretical understanding for its efficacy. Moreover, the LiCoO<SUB>2</SUB>/Li cell incorporating CPL exhibits excellent cycling stability up to 400 cycles at 1 mA cm<SUP>−2</SUP> (1 C-rate), which demonstrates practical applicability in Li ion batteries through replacing the graphite anode with a CPL-coated Li metal anode.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Composite protective layer (CPL) was introduced in Li metal-based batteries (LMB). </LI> <LI> Stable Li plating/stripping at high current density (10 mA cm<SUP>−2</SUP>) became possible. </LI> <LI> The CPL is capable of mechanically suppressing of Li dendrite formation. </LI> <LI> The shear modulus of the CPL is nearly 2 times larger than that of Li. </LI> <LI> Enhanced cycle performance of LiCoO<SUB>2</SUB>/Li cell with the CPL at 1 mA cm<SUP>−2</SUP> (400 cycles). </LI> </UL> </P>

Sodium zinc hexacyanoferrate with a well-defined open framework as a positive electrode for sodium ion batteries

Lee, Hongkyung,Kim, Yong-Il,Park, Jung-Ki,Choi, Jang Wook The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.67

<P>A modified Prussian blue analogue, Na<SUB>2</SUB>Zn<SUB>3</SUB>[Fe(CN)<SUB>6</SUB>]<SUB>2</SUB>·<I>x</I>H<SUB>2</SUB>O, was investigated as a positive electrode material. Utilizing a well-defined channel structure, the compound exhibits a clear electrochemical activity at around 3.5 V <I>vs.</I> Na/Na<SUP>+</SUP> with a reversible capacity of 56.4 mA h g<SUP>−1</SUP> and good cycle life.</P> <P>Graphic Abstract</P><P>Na<SUB>2</SUB>Zn<SUB>3</SUB>[Fe(CN)<SUB>6</SUB>]<SUB>2</SUB>·<I>x</I>H<SUB>2</SUB>O exhibits good electrochemical activity at around 3.5 V <I>vs.</I> Na/Na<SUP>+</SUP> and a reversible capacity of 56.4 mA h g<SUP>−1</SUP> in sodium batteries. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc33771a'> </P>

국세징수법에 의한 채권압류 및 대위와 상계적상 - 대상판결 : 대법원 2022. 12. 16. 선고 2022다218271 판결 -

이홍경 ( Lee Hongkyung ),김제완 ( Kim Jewan ) 고려대학교 법학연구원 2024 고려법학 Vol.- No.113

대상판결은 국세징수법에 의한 국가 및 지방자치단체의 채권의 압류와 체납액의 한도로 행사한 대위권의 상계와 관련한 판단이다. 대상판결은 본건 청구가 조세법상의 압류채권에 대한 대위로서 추심행위를 한 것이고, 민사집행법상의 추심금 청구가 아니라는 점을 간과한 것으로 생각한다. 과세관청은 조세법상의 대위권을 행사하여 그 지급을 청구하였고 금전으로 직접 지급을 명하는 판결을 받았다. 그러나 대상판결에서는 추심의 소를 제기한 것으로 오인하여 추심채권자의 상계에 관한 법리로 판결하여 과세관청이 패소한 사건이다. 과세관청이 채권자대위권 행사시 채권자대위권에 있어서 상계가능성에 대한 주된 검토 대상은 과세관청이 체납자에 대하여 보유하고 있는 조세채권과 체납자가 과세관청에 대하여 보유하는 피압류채권 대금 반환채권간의 상계여부이다. 즉 피압류채권과 제3채무자가 압류채권자(과세관청)에 대하여 보유하는 채권의 상계가능성은 채권자대위권 행사시 상계에 관한 법리로서는 다루어지고 있지 아니하다. 설사 피압류채권과 제3채무자의 압류채권자에 대한 채권간 상계를 논하는 경우에도 피압류채권의 귀속에 변경이 발생하지 아니하는 한 결국은 상호대립성이 인정되지 아니한 채권간의 상계 허용여부와 동일한 사안으로 검토될 수 밖에 없다. 이러한 점에서 강제징수에 있어서 과세관청이 압류채권자의 지위에서 행사하는 채권자대위권을 추심과 구별하는 입장을 취할 실익이 크지 않다고 볼 수도 있다. 그러나 조세는 국가 또는 지방자치단체가 존립하기 위한 재정적 기초를 이루기 위한 목적으로 징수가 확보되어야 하는 조세의 공익성에 기초한 조세채권자에 대한 절차법상 자력집행권과 실체법상의 조세 우선권이 있어 지방세징수법 제53조등을 근거로 압류금 지급청구의 소에서 승소하였다면 그 채권은 오롯이 국가에 귀속될 뿐 다른 채권자와의 배분은 요구되지 않는다고 해석되어야 한다. The Supreme Court Judgement studied in this thesis(hereinafter referred to as the “Subject Case”) pertains to the determination of subrogation rights exercised within the limits of the seizure of national and local government claims and the amount of default under the National Tax Collection Act. The Judgement asserts that the claim concerned was filed to collect debt based on subrogation as a creditor under tax laws but not a claim to seek money claimed to be owed under th Civil Execution Act. The tax authorities demanded payment by exercising their subrogation rights under tax laws and obtained a Subject Case directing direct payment in monetary terms. However, the Subject Case misinterpreted the plaintiff's claim as a lawsuit for collection, ruling on the laws pertaining to the right of set-off by a debt collecting creditor, resulting in the tax authorities losing the case. When tax authorities exercise creditor subrogation rights, the main consideration for the possibility of set-off lies in whether there can be an set-off between the tax claims held by the tax authorities against the defaulters and the claims for the return of withheld amounts held by the defaulters against the tax authorities. In other words, the possibility of offsetting the claim between the withheld amount and the claim held by the second obligor against the execution creditor(tax authorities) is not addressed as a legal principle regarding set-off when exercising creditor subrogation rights. Even in cases where discussion takes place to offset between the claims of the withheld amount and the execution creditor of the third obligor, if there is no change in the ownership of the withheld amount, ultimately, it must be considered as a matter similar to the allowance of set-off between conflicting claims and whether they are recognized. In this regard, for forced collection, it can be seen that tax authorities are no likely to have the capability to distinguish subrogation rights exercised as an execution creditor from actual debt collection. However, tax laws are based on the public interest of taxation, which must secure tax collection as the financial foundation for the existence of the state or local governments. Therefore, if the claim for seizure money under tax laws is won based on the right of self-execution in procedural law and the priority right of tax in substantive law, as interpreted according to Article 53 of the Local Tax Collection Law, the debt should be interpreted as owed solely to the state, and not requiring any distribution among other creditors.

Sustainable Li-metal Protection in Li-S Batteries with Lean Electrolyte

이홍경(Hongkyung Lee),최보경 한국고분자학회 2024 한국고분자학회 학술대회 연구논문 초록집 Vol.49 No.1

전극 계면 회생법을 통한 리튬이차전지 재활용 기술

이지원(Jiwon Lee),장승혜(Seunghye Jang),최주영(Juyoung choi),한인경(Inkyung Han),안형국(Hyeongguk An),이홍경(Hongkyung Lee) 한국전지학회 2022 한국전지학회지 Vol.2 No.1

현 폐배터리 재활용 기술은 배터리 파쇄 과정에서의 폭발 위험과 활물질 회수에 사용되는 용매의 환경 유해성으로 개선이 필요하다. 본 연구에서는 폐배터리 파쇄 없이 전극을 세척하여 계면을 회생시킬 수 있는 계면 세척제 및 원활한 세척을 위한 신규 전극 구조를 소개한다. 열화된 전극의 SEI 성분을 제거할 수 있는 용매를 탐색하고 기공성 집전체 기반의 전극을 제작하여 효과적인 전극 세척을 도모하였다. 본 연구에서 제안하는 계면회생기술의 효용성 입증을 위해 배터리 재조립 및 임피던스 분광법을 통한 계면 저항의 감소를 확인하였다. Conventional battery recycling has suffered from the risk of explosion during the battery disposal process and the use of environmental hazard chemicals for recovering precious metals such as Li, Ni, and Co. This study presents the electrode surface cleaning solutions and optimal electrode structures for cleaning the waste battery entirely without disassembly. Solvents that can dissolve solid-electrolyte interphase (SEI) components on the used electrode were explored, and an electrode with perforated current collectors was manufactured to facilitate the washing throughout. D₂O solvent can completely remove the side products and recover the original surface of a graphite anode, as confirmed by FT-IR. EIS study by constructing re-assembled cells with D₂O-washed electrodes revealed that the interface resistance was reduced by 41.6% owing to SEI removal. Moreover, the Gr||LCO cells re-assembled after cell failure achieved 82% (115 mAh g<SUP>-1</SUP>) of the original capacity.

Enhancing the Cycling Stability of Sodium Metal Electrodes by Building an Inorganic–Organic Composite Protective Layer

Kim, Yun-Jung,Lee, Hongkyung,Noh, Hyungjun,Lee, Jinhong,Kim, Seokwoo,Ryou, Myung-Hyun,Lee, Yong Min,Kim, Hee-Tak American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.7

<P>Owing to the natural abundance of sodium resources and their low price, next-generation batteries employing an Na metal anode, such as Na-O-2 and Na-S systems, have attracted a great deal of interest. However, the poor reversibility of an Na metal electrode during repeated electrochemical plating and stripping is a major obstacle to realizing rechargeable sodium metal batteries. It mainly originates from Na dendrite formation and exhaustive electrolyte decomposition due to the high reactivity of Na metal. Herein, we report a free-standing composite protective layer (FCPL) for enhancing the reversibility of an Na metal electrode by mechanically suppressing Na dendritic growth and mitigating the electrolyte decomposition. A systematic variation of the liquid electrolyte uptake of FCPL verifies the existence of a critical shear modulus for suppressing Na dendrite growth, being in good agreement with a linear elastic theory, and emphasizes the importance of the ionic conductivity of FCPL for attaining uniform Na plating and stripping. The Na Na symmetric cell with an optimized FCPL exhibits a cycle life two times longer than that of a bare Na electrode.</P>