Journal of the Korean Electrochemical Society Vol. 22, No. 2, 2019, Research Paper pissn eis

Size: px

Start display at page:

Download "Journal of the Korean Electrochemical Society Vol. 22, No. 2, 2019, Research Paper pissn eis"

서진 기
3 years ago
Views:

1 Journal of the Korean Electrochemical Society Vol. 22, No. 2, 2019, Research Paper pissn eissn 미세패턴화된리튬금속전극의 Vinylene Carbonate 첨가제도입에따른전기화학특성에관한연구 진다희 1,2 박주남 1 Cyril Bubu Dzakpasu 1 윤별희 2 유명현 2, ** 이용민 1, * 1 대구경북과학기술원에너지공학전공, 2 한밭대학교화학생명공학과 (2019 년 5 월 15 일접수 : 2019 년 5 월 21 일수정 : 2019 년 5 월 21 일채택 ) Effect of Vinylene Carbonate as an Electrolyte Additive on the Electrochemical Properties of Micro-Patterned Lithium Metal Anode Dahee Jin 1,2, Joonam Park 1, Cyril Bubu Dzakpasu 1, Byeolhee Yoon 2, Myung-Hyun Ryou 2, **, and Yong Min Lee 1, * 1 Department of Energy Science and Engineering Daegu Gyeongbuk Institute of Science and Technology (DGIST) 2 Department of Chemical and Biological Engineering, Hanbat National University (Received May 15, 2019 : Revised May 21, 2019 : Accepted May 21, 2019) 초 록 리튬금속음극은낮은환원전위, 고에너지밀도로인해흑연을대체할차세대음극재로재조명받고있다. 하지만, 충방전시리튬금속표면에서의반복적인산화 / 환원반응에의해리튬덴드라이트가형성되며이로인해수명특성이급격하게저하되고더나아가내부단락 (Internal Short-circuit) 과같은안전성문제로인해상용화되기에는어려운실정이다. 이를해결하기위해본연구그룹에서는리튬금속에미세패턴을형성하여전류밀도를제어함으로써덴드라이트형성을제어하였으나, 고전류밀도에서는리튬덴드라이트의형성을완벽하게제어할수는없었다. 본연구에서는미세패턴화된리튬금속전극에전해질첨가제 Vinylene Carbonate(VC) 를도입하여고율충방전시미세패턴화된리튬금속전극의덴드라이트형성억제를극대화하고자하였다. 미세패턴화된리튬금속전극과 VC 첨가제의시너지효과로인해높은전류밀도에서의리튬덴드라이트가비교적치밀하게형성되는것을확인할수있었다. 이로인해 300 사이클동안 88.3% 의용량유지율을보였으며, 기존의미세패턴화된리튬금속전극에대비하여수명특성이약 6 배이상향상된것을확인할수있었다. Abstract : Lithium metal anode with the highest theoretical capacity to replace graphite anodes are being reviewed. However, the dendrite growth during repeated oxidation/reduction reaction on lithium metal surface, which results in poor cycle performance and safety issue has hindered its successful implementation. In our previous work, we solved this problem by using surface modification technique whereby a surface pattern on lithium metal anode is introduced. Although the micro-patterned Lithium metal electrode is beneficial to control Li metal deposition efficiently, it is difficult to control the mossy-like Li granulation at high current density * yongmin.lee@dgist.ac.kr (Y.M. Lee), mhryou@hanbat.ac.kr (M.-H. Ryou) 69

2 70 J. Korean Electrochem. Soc., Vol. 22, No. 2, 2019 (>2.0 ma cm -2 ). In this study, we introduce vinylene carbonate (VC) electrolyte additive on micro patterned lithium metal anode to suppress the lithium dendrite growth. Owing to the synergetic effect of micro-patterned lithium metal anode and VC electrolyte additive, lithium dendrite at a high current density is dense. As a result, we confirmed that the cycle performance was further improved about 6 times as compared with the reference electrode. Key words : Vinylene Carbonate, Electrolyte Additive, Patterned Lithium Metal Anode, Lithium Dendrite, Lithium Secondary Battery 1. 서론 리튬이온전지 (Lithium-ion Batteries, LiB) 는고출력및고에너지밀도를장점으로소형 IT 디바이스뿐만아니라전기자동차 (Electric Vehicles, EVs) 및에너지저장시스템 (Energy Storage Systems, ESSs) 과같은중대형전지시스템의주전원소자로써적용범위가확대되고있다. 1-4) 특히전기자동차에대한수요가지속적으로증대됨에따라전기자동차의주행거리를내연기관수준으로늘리는것이가장큰이슈로대두되고있다. 하지만현재 Ni 함량이높은 NCM 계열의양극과흑연조합의리튬이온전지로는내연기관수준의주행거리를달성하는것은어려운실정이며흑연을리튬금속음극으로대체함으로써이를해결고자하는시도가다시주목되고있다. 5) 리튬금속음극은가장낮은환원전위 (-3.04V vs SHE), 높은에너지밀도 (3860mAh g -1, 2060mAh cm -3 ) 로인해가장이상적인음극으로여겨지고있다. 6,7) 그럼에도불구하고, 리튬금속음극의몇가지문제점으로인해상용화되기에는한계가존재한다. 리튬금속음극은표면에서의반복적인산화환원반응을통해리튬금속표면과액체전해질사이에 Solid Electrolyte Interphase(SEI) 를생성하게된다. 8,9) 충방전과정동안불균일한리튬금속음극표면에수지상의리튬금속덴드라이트가성장하게되며이로인해지속적으로전해질분해가일어나게되고전지의급격한용량감소로이어지게된다. 그뿐만아니라, 리튬금속덴드라이트가성장되거나물리적으로박리되어분리막을뚫고양극과접촉하면내부단락 (Shortcircuit) 이발생될수있으며이는안전성의문제를일으킬수있다. 4,10,11) 따라서, 리튬금속을음극으로써적용하기위해서는덴드라이트를억제하는기술개발이필수적으로선행된다. 이를해결하기위해최근 1) 기능성전해질의사용 2,12-15), 2) 3D Hosting 물질의사용 16-20), 3) 분리막개질 21-25) 4) 리튬금속표면개질 26-32) 등다양한방면에서리튬금속의덴드라이트를억제하고자하는연구가진행되고있다. 특히본연구그룹에서는리튬금속표면에 미세패턴을형성하여표면의전류밀도를제어하고, 리튬금속표면의불규칙한 Native Layer를균일화및제거함으로써리튬금속이패턴내부로증착되도록유도하였다 26,29,31). 리튬금속덴드라이트를효과적으로제어함으로인해전기화학적특성이크게향상되었지만, 높은전류밀도에서는리튬덴드라이트를완전히억제하지못하고, 이끼상 (Mossy-like) 의덴드라이트가패턴내부에형성되는것을확인하였다. 이와같이표면적이큰덴드라이트를형성하는것은지속적으로전해질소모를유도하며리튬금속기반의전지성능에악영향을미칠수있다. 33,34) 리튬금속음극의덴드라이트를억제하기위해서는리튬금속표면에매우안정하고견고한 SEI를형성하는것이필수적이다 8,9). 이를해결하기위해전해질조성을최적화하거나소량의기능성첨가제를첨가하는것은가장효율적이고경제적인방법으로대두되고있다. 소량의전해질첨가제는리튬금속표면에손쉽게균일하고견고한 SEI를형성할수있으며이는반복되는충방전과정에서의전해질분해를방지하고덴드라이트를억제할수있다. 이를위한전해질첨가제는 VC (Vinylene Carbonate) 12,35-39), FEC (Fluoroethylene Carbonate) 40-44), SA (Succinic Anhydride) 45-47), TPSA(2-(triphenylphosphoranylidene) succinic anhydride) 46,48) 등이제시되고있으며그중 VC는상용화된전지에가장널리사용되고있다. VC는전해질내에약 ~5% 정도로소량을첨가함으로써리튬금속음극표면에 poly(vc) 성분의안정적이고견고한 SEI가형성되어수명특성을크게향상시킬수있다 ) 따라서본연구에서는높은전류밀도에서미세패턴화된리튬금속의리튬덴드라이트형성을비교적안정화하기위해전해질첨가제로써 VC를 5wt% 가량첨가하였다. 미세패턴화된리튬금속과 VC 전해질첨가제의시너지효과로인해고전류밀도에서리튬덴드라이트가비교적치밀하게증착되었으며이로인해전기화학적성능이크게향상됨을확인하였다. 또한, 이를 Galvanostatic Cycling, 전계방출주사현미경, X선광전자분광표면분석을통해보다더자세히확인하였다.

3 전기화학회지, 제 22 권, 제 2 호, 실험방법 2.1 전극제조양극활물질 90 wt% Li(Ni 0.6 Co 0.2 Mn 0.2 )O 2 (NCM622, L&F Co., Ltd., Korea), 5 wt% 도전재 (Super-P Li, Imerys, Belgium), 고분자바인더로는 5 wt% polyvinylidene Fluoride (PVdF, KF- 1300, Kureha Battery Materials Co., Japan, M w = 350,000) 를 N-methyl-2-pyrrolidone (NMP, Sigma- Aldrich, USA) 용매를사용하여혼합한후슬러리를제조하였다. 이때제조된바인더는 NMP용매에 10 wt% PVdF를녹여서사용하였다. 이를닥터블레이드를이용하여알루미늄집전체 (15 µm, Sam-A Aluminum, Korea) 위에코팅하였다. 제조된전극을 130 o C에서 1 h 건조한후, Roll Presser (CLP-2025, CIS, Korea) 를이용하여전극의두께와밀도를조절하였다. 제조된양극의 Loading Level은 10.35mgcm -2, 밀도는 2.3gcm -3 으로제어하여평가하였다. 2.2 코인셀조립전기화학적특성을평가하기위해반쪽전지 (Halfcell) 를 2032-type coin cell을제조하였다. 제조된 NCM622 양극은지름 12 mm의원모양으로펀칭한후, 80 o C에서 12시간동안진공건조하여사용하였다. 패턴화된 Li metal(100 µm, Honjo Metal Co, Japan) 은지름 16.2 mm의원모양으로분리막 (Polyethylene, PE, 20 µm, ND420, Asahi Kasei E- materials, Japan) 은지름 18 mm의원모양으로펀칭하여사용하였다. Reference 전해액은 1.15 M LiPF 6 in EC (Ethylene Carbonate)/ EMC(Ethylene Carbonate) (3/7, v/v, ENCHEM, Korea) 을사용하였으며대조군은 Reference 전해액에 VC를 5wt% 를첨가하여사용하였다. 각단전지내의전해질의양은 200 µl로제어되었다. 상기전극및분리막은 Argon gas 분위기의 Glove Box내에서조립되었다. ( 이슬점 - 80 o C) 2.3 전기화학적특성평가각단위전지는조립후 12 h 의 Aging 후에, C/ 10 (0.158mA cm -2 ) 의전류밀도로정전류 (Constant Current, CC) 조건에서 3.0~4.3V, 25 o C 에서충 방전되어 Formation 단계를거쳤다. (PNE Solution, Korea) Formation 단계이후, C/5 (0.317 ma cm -2 ) 의전류밀도로정전류 / 정전압 (Constant Current/Constant Voltage, CC/CV) 조건으로안정화 (Stabilization) 단계를진행하였다. ( 전압영역 : 3.0 ~ 4.3 V, 온도 : 25 o C). Formation 과 Stabilization 단계를총칭하여초기사이클 (Precycling) 이라한다. 단위전지는초기사이클단계를거친이후 C/2 (CC/CV Mode, ma cm -2 ) 충전, C/2, 1C, 2C, 3C, 5C, 7C, 10C, 15C, C/2 (CC Mode, ma cm -2, ma cm -2, ma cm -2, ma cm ma cm -2, ma cm -2, ma cm -2, ma cm -2, ma cm -2 ) 방전조건으로 3.0~4.3 V cut off에서각각 5cycle 을반복함으로써출력특성을평가하였다. 수명특성은 1C (CC/CV mode, ma cm -2 ) 충전, 1C (CC mode, ma cm -2 ) 를반복하여전지의용량감소율을확인하였다. 2.4 전기화학적분석리튬금속음극표면의리튬덴드라이트의몰폴로지 (Morphology) 를확인하기위해초기사이클이후, 2mAcm -2 전류밀도로 5 분동안전류를인가해준이후단위전지를분해하여전계방출주사현미경 (FE- SEM, Hitachi S-4800, Japan) 분석을실시하였다. 또한패턴화된리튬금속의표면 SEI 성분을분석하기위해초기사이클단계이후제조된단전지를분해하였다. 초기사이클단계에사용되었던패턴화된리튬금속음극을 DMC 용매를사용하여세척하였으며이를글러브박스내의챔버에 12 시간동안건조하였다. 건조된패턴화된리튬금속음극을 X 선광전자분광표면 (XPS, ESCALAB 250Xi, Thermo Scientific) 분석을실시하였다. 3. 결과및고찰 미세패턴화된리튬금속음극을제작하기위해스테인리스강재질의 2cm 2cm 의스탬프를제작하였다. 제작된스탬프의패턴몰폴로지를확인하기위해 Optic Microscope 및 3D Mapping 한이미지를측정하였으며이를 Fig. 1 에나타내었다. Fig. 1 (a) 를보면, 스탬프에전체적으로피라미드상의패턴이균일하게형성되어있었다. 또한, 3D Mapping 한이미지 (Fig. 1 (b), (c)) 를통해각피라미드팁의길이는약 50 µm, 가로및세로는 50 µm 그리고각각의피라미드팁은서로 100 µm 가량의간격을갖는것을확인하였다. 이를통해실험에사용되는스탬프의몰폴로지가이전연구에서시뮬레이션을통해최적화된몰폴로지와비슷한수준임을알수있었다. 26) 이를이용하여 100 µm 기반리튬금속음극에미세패턴을형성한이후, Li/Li Symmetric Cell 을제조하여 Galvanostatic Cycling Test 를진행함으로써리튬금속의 Plating, Stripping 거동을확인하고자하였다. (Fig. 2) 충전, 방전전류밀도는 0.5 ma cm -2 로 30 분동

72 J. Korean Electrochem. Soc., Vol. 22, No. 2, 2019 Fig. 1. (a) Optic images and (b, c) 3D mapping image of 2 cm 2 cm stainless-steel stamp by using digital microscope.

4 72 J. Korean Electrochem. Soc., Vol. 22, No. 2, 2019 Fig. 1. (a) Optic images and (b, c) 3D mapping image of 2 cm 2 cm stainless-steel stamp by using digital microscope. 안전류를인가하였으며충전방전각각의과정사이에는 10 분의휴지시간을주었다. Galvanostatic Cycling Test 결과, Reference 전해액에대비하여 5wt% 의 VC 가첨가된전해액이더낮은과전압을형성하는것을확인할수있었다. 5 wt% VC 가첨가된전지의경우, VC 가환원되는전압 (Reduction Potential = 1.06 V vs. Li/Li +, Table 1 참고 ) 내에서전지가구동하였기때문에 VC 가전해액보다먼저환원되어안정하고견고한 SEI 를형성시킬수있었다. 54,55) Table 1. HOMO and LUMO energy levels of ethylene carbonate(ec), ethyl methyl carbonate(emc) and, vinylene carbonate(vc), and their reduction potentials. Material Ethylene Carbonate (EC) Ethyl methyl Carbonate (EMC) Vinylene Carbonate (VC) HOMO (ev) LUMO (ev) Reduction potential (V vs. Li/Li + ) Fig. 2. Potential profiles of Li/Li symmetrical cells during galvanostatic cycling [+0.5 ma cm -2 (30 min) Rest (10min) 0.5 ma cm -2 (30 min) Rest (10min)]. 따라서, 추가적인전해액분해를막아주고안정한 SEI 층에의해덴드라이트의형성을제어함으로써 Reference 전해액이적용된전지대비하여낮은과전압을형성하였을것이라고생각된다. 이에대한리튬금속의덴드라이트형성메커니즘에대하여자세히알아보기위해 Li/Li Symmetric Cell 을제조한후높은전류밀도 (2 ma cm -2, 5min, SOC 10% 수준 ) 로전류를인가해준이후리튬금속덴드라이트의몰폴로지를확인하였다. (Fig. 3) SEM Image 측정결과, 두전지모두리튬덴드라이트가패턴내부로증착되는것을확인할수있었으나리

전기화학회지, 제 22 권, 제 2 호, 2019 73 Fig. 3. SEM images of (a, b, c) Reference, (d, e, f) 5 wt% VC with Micro-Patterned Lithium anode after plating with a current density of 2 ma cm -2. Fig. 4.

5 전기화학회지, 제 22 권, 제 2 호, Fig. 3. SEM images of (a, b, c) Reference, (d, e, f) 5 wt% VC with Micro-Patterned Lithium anode after plating with a current density of 2 ma cm -2. Fig. 4. Voltage profiles of Li (Ni 0.6 Co 0.2 Mn 0.2 ) O 2 electrodes (a) without VC and (b) with VC electrolyte additive during precycling. 튬덴드라이트의몰폴로지는다른것을확인할수있었다. Fig. 3(a), 3(b), 3(c) 를보면 Reference 전해액이적용된전지의경우높은전류밀도에서표면적이큰이끼상의덴드라이트가성장되었으며이는이전의연구와같은경향을보였다. 26) 이러한형태의덴드라이트는액체전해질을지속적으로분해되도록함으로써전지의열화를가속화할수있기때문에전지의장기적인수명에서는악영향을미칠수있다. 이에반해, 5 wt% VC 가첨가된전지의경우, 패턴내부로비교적치밀한형태의리튬금속덴드라이트가성장되었다 (Fig. 3(d), 3(e), 3(f)). VC 첨가제도입에따른미세패턴화된리튬금속음극의전기화학적특성을알아보기위해 NCM622/ Li 반쪽전지평가를진행하였다. Fig. 4 는첨가제도 입유무에따른전지의초기전압곡선을나타내고있다. 초기충방전효율, 용량이나전압곡선의개형은첨가제도입유무에의한유의차없이진행되었다. 하지만, Formation 과정의충전개형을면밀히살펴보면, 5wt% 의 VC가도입된전지의경우과전압이낮게형성되었으며낮은율속으로초기충방전과정을진행하였기때문에초기충방전효율및비용량은동등수준임을확인하였다. (Reference Discharge Capacity = mah g -1 (88.6%), 5 wt% VC Discharge Capacity = mah g -1 (89.3%)) 이는첨가제도입으로인해리튬금속덴드라이트의몰폴로지를잘제어되었기때문에초기의과전압이낮게형성되었다. 초기충방전단계에서 VC 첨가제유무에따른전기화학적특성을더욱면밀히분석하기위해초기사

74 J. Korean Electrochem. Soc., Vol. 22, No. 2, 2019 Fig. 5. SEM images of (a, c) Reference and (b, d) 5 wt% VC with Micro-patterned lithium metal electrodes after precycling. Fig. 6.

6 74 J. Korean Electrochem. Soc., Vol. 22, No. 2, 2019 Fig. 5. SEM images of (a, c) Reference and (b, d) 5 wt% VC with Micro-patterned lithium metal electrodes after precycling. Fig. 6. C 1s XPS spectra of the micro-patterned lithium metal anodes (a) without and (b) with VC after precycling. 이클단계이후전지를분해하여 SEM Image(Fig. 5) 및 X-ray 광전자분광법 (XPS) (Fig. 6) 분석을진행하였다. Fig. 5(a), 5(c) 를보면, VC 첨가제가적용되지않은경우, 초기충방전단계동안패턴내의리튬소모가크게진행되었기때문에패턴의모양이변형되었다. 또한불안정한 SEI 에의해패턴외부로리튬금속덴드라이트가넘치게형성되는것을확인하였다. 반면에, 5 wt% 의 VC 첨가제가도입된전지의경우비교적패턴내부로만덴드라이트가증착되었다. 이는앞선 Fig. 3(d), 3(e), 3(f) 와같은결과로, VC 첨가제가도입된경우안정하고저항특성이낮은 SEI 가형성될뿐만아니라치밀한덴드라이트가형성되었기때문으로해석된다. VC 첨가제도입에의한 SEI 개질효과를알아보기위해미세패턴화된리튬금속표면에형성된 SEI 의화학적조성을 XPS 를이용하여분석하였다. Fig. 6 을보면 VC 첨가제유무에따른미세패턴화된리튬금속표면의 C1s 의고해상도 XPS 스펙트럼을나타냈다. 결합에너지기반으로각성분을분석하면 Reference 전해액의경우, 유기용매인 EC, EMC 가환원됨에따라생기는 C-C peak( 약 ev), C-O Peak( 약 ev), Li 2 CO 3 Peak( 약 ev) 이형성되는것을확인하였다. 반면에, VC 첨가제가도입된전지에서는 C-C peak( 약 284.6eV) 보다는 Poly(VC) 의구성성분인 C-O Peak( 약 286.8eV), C=O Peak( 약 ev) 그리고 Li 2 CO 3 Peak( 약

7 전기화학회지, 제 22 권, 제 2 호, eV) 의크기가증가하였다. 이를통해전해액내의리튬염과용매가분해되기전에 VC 가먼저환원되어리튬금속표면에안정한 SEI 를형성하였다고판단할수있다. 또한, 이러한 VC 환원분해산물로인해전해액의지속적인소모와덴드라이트형성을비교적잘억제할수있었다. 이와같은결과를토대로, 실제전지내에서의 VC 첨가제의효과를확인하기위해 NCM622 양극기반의반쪽전지의전기화학적평가를진행하였다. (Fig. 7) 출력특성평가는충전율속을 0.5 C (0.797 ma cm -2 ) 로고정한후방전율속을증가하면서진행되었으며그결과, 첨가제가적용된전지의출력특성이크게향상되었다. (Fig. 7(b)) 수명특성평가는충방전속도를 1C (1.584 ma cm -2 ) 수준으로하여진행되었으며그에대한결과는 Fig. 7(b) 에나타내었다. 수명특성평가결과, Reference 전지의경우약 55 회의충방전이후초기용량의 80% 밖에유지하지못하였으며, 리튬덴드라이트의성장및지속적인전해질분해에의한전지의열화현상이진행되어이후충방전사이클에서급격하게전지의비용량이줄어들었다. 이러한급격한수명특성저하의원인은 1C (1.584 ma cm -2 ) 수준의높은전류밀도조건및박막의리튬금속 (100 µm) 기반에서전지를구동하였기때문이다. 반면에, 5 wt% 의 VC 가첨가된전지는비교적치밀한덴드라이트의형성으로인해전해질분해를억제되었으며이로인해높은전류밀도하에서도 300 Cycle 동안초기용량의 88.3% 를유지하고있었다. 또한, Reference 전지의경우충방전이진행될수록충방전효율이감소하는것에비해 5wt% 의 VC 를첨가한전지의충방전효율은 100% 에가깝게유지되었다. 4. 결론 Fig. 7. Electrochemical performance of NCM622/Li cells employing Micro-patterned Lithium metal electrodes with and without VC electrolyte additive (a) Comparison of the discharge capacities of the cells at different discharge rates from 0.5C (0.792 ma cm -2 ) to 15C (23.76 ma cm -2 ) while keeping the charge rate constant at 0.5C (0.792 ma cm -2 ). (b) Cycling performance measured at a rate of 1C (1.584 ma cm -2 ) between 3.0 V and 4.3 V (vs. Li/Li + ) (c) Columbic efficiencies of unit cells relevant to Fig. 7b. 본연구에서는미세패턴화된리튬금속음극과 VC 전해질첨가제의시너지효과로인한리튬덴드라이트성장억제를통한전기화학적성능향상을보고한다. VC 전해질첨가제도입으로인해형성된 SEI 는 poly(vc) 성분이많이존재하여더낮은저항특성을나타내었다. 그결과높은전류밀도에서도리튬덴드라이트가패턴내로더치밀하게형성되는것이확인하였다. 따라서, 기존의미세패턴화된리튬금속음극보다낮은전지저항과수명특성이약 6 배정도향상된결과를나타내었다. 본연구는비교적쉽고간단한방법을통해리튬금속음극의덴드라이트를효과적으로억제하고전기화학적성능을향상시켰다는점에서의미가있다.

8 76 J. Korean Electrochem. Soc., Vol. 22, No. 2, 2019 감사의글 This work was supported by Technology Development Program(S ) funded by the Ministry of SMEs and Startups(MSS, Korea) and by the Technology Innovation Program ( ) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by the Ministry of Trade, Industry & Energy (MI, Korea). 인용문헌 1. M. Armand and J.-M. Tarascon, Building better batteries, Nature 451, 652, (2008). 2. H. Xiang, P. Shi, P. Bhattacharya, X. Chen, D. Mei, M. E. Bowden, J. Zheng, J.-G. Zhang and W. J. J. o. P. S. Xu, Enhanced charging capability of lithium metal batteries based on lithium bis (trifluoromethanesulfonyl) imide-lithium bis (oxalato) borate dual-salt electrolytes, Jornal of Power Sources 318, , (2016). 3. L. Lu, X. Han, J. Li, J. Hua and M. Ouyang, A review on the key issues for lithium-ion battery management in electric vehicles, Journal of power sources 226, , (2013). 4. J.-M. Tarascon and M. Armand, in Materials for Sustainable Energy: A Collection of Peer-Reviewed Research and Review Articles from Nature Publishing Group, World Scientific 2011, p Q. Hu, The renaissance of lithium metal: SolidEnergy s role in the future of lithium batteries, Nature 526, 4-10, (2015). 6. W. Xu, J. Wang, F. Ding, X. Chen, E. Nasybulin, Y. Zhang and J.-G. Zhang, Lithium metal anodes for rechargeable batteries, Energy Environmental Science 7, , (2014). 7. D. Lin, Y. Liu and Y. Cui, Reviving the lithium metal anode for high-energy batteries, Nature nanotechnology 12, 194, (2017). 8. X. B. Cheng, R. Zhang, C. Z. Zhao, F. Wei, J. G. Zhang and Q. Zhang, A review of solid electrolyte interphases on lithium metal anode, Advanced Sicence 3, , (2016). 9. P. Verma, P. Maire and P. Novák, A review of the features and analyses of the solid electrolyte interphase in Li-ion batteries, Electrochimica Acta 55, , (2010). 10. Z. Li, J. Huang, B. Y. Liaw, V. Metzler and J. Zhang, A review of lithium deposition in lithium-ion and lithium metal secondary batteries, Journal of power sources 254, , (2014). 11. K. N. Wood, E. Kazyak, A. F. Chadwick, K.-H. Chen, J.- G. Zhang, K. Thornton and N. P. Dasgupta, Dendrites and pits: Untangling the complex behavior of lithium metal anodes through operando video microscopy, ACS central science 2, , (2016). 12. H. Ota, K. Shima, M. Ue and J.-i. Yamaki, Effect of vinylene carbonate as additive to electrolyte for lithium metal anode, Electrochimica Acta 49, , (2004). 13. J. Zheng, M. H. Engelhard, D. Mei, S. Jiao, B. J. Polzin, J.-G. Zhang and W. Xu, Electrolyte additive enabled fast charging and stable cycling lithium metal batteries, Nature Energy 2, 17012, (2017). 14. L. Suo, W. Xue, M. Gobet, S. G. Greenbaum, C. Wang, Y. Chen, W. Yang, Y. Li and J. Li, Fluorine-donating electrolytes enable highly reversible 5-V-class Li metal batteries, Proceedings of the National Academy of Sciences 115, , (2018). 15. S. Jiao, X. Ren, R. Cao, M. H. Engelhard, Y. Liu, D. Hu, D. Mei, J. Zheng, W. Zhao and Q. Li, Stable cycling of high-voltage lithium metal batteries in ether electrolytes, Nature Energy 3, 739, (2018). 16. X. B. Cheng, T. Z. Hou, R. Zhang, H. J. Peng, C. Z. Zhao, J. Q. Huang and Q. Zhang, Dendrite-free lithium deposition induced by uniformly distributed lithium ions for efficient lithium metal batteries, Advanced Materials 28, , (2016). 17. H. Jo, D. Song, Y.-C. Jeong, Y. M. Lee and M.-H. Ryou, Study on dead-li suppression mechanism of Li-hosting vapor-grown-carbon-nanofiber-based protective layer for Li metal anodes, Journal of power sources 409, , (2019). 18. H. Lee, J. Song, Y.-J. Kim, J.-K. Park and H.-T. Kim, Structural modulation of lithium metal-electrolyte interface with three-dimensional metallic interlayer for high-performance lithium metal batteries, Scientific reports 6, 30830, (2016). 19. Y. Liu, D. Lin, Z. Liang, J. Zhao, K. Yan and Y. Cui, Lithium-coated polymeric matrix as a minimum volumechange and dendrite-free lithium metal anode, Nature communications 7, 10992, (2016). 20. W. Liu, D. Lin, A. Pei and Y. Cui, Stabilizing lithium metal anodes by uniform Li-ion flux distribution in nanochannel confinement, Journal of the American Chemical Society 138, , (2016). 21. W.-K. Shin, A. G. Kannan and D.-W. Kim, Effective suppression of dendritic lithium growth using an ultrathin coating of nitrogen and sulfur codoped graphene nanosheets on polymer separator for lithium metal batteries, ACS applied materials & interfaces 7, , (2015). 22. M. H. Ryou, D. J. Lee, J. N. Lee, Y. M. Lee, J. K. Park and J. W. Choi, Excellent cycle life of lithium-metal anodes in lithium-ion batteries with mussel-inspired polydopamine-coated separators, Advanced Energy Materials 2, , (2012). 23. H. Jeon, S. Y. Jin, W. H. Park, H. Lee, H.-T. Kim, M.-H. Ryou and Y. M. Lee, Plasma-assisted water-based Al2O3 ceramic coating for polyethylene-based microporous separators for lithium metal secondary batteries,

9 전기화학회지, 제 22 권, 제 2 호, Electrochimica Acta 212, , (2016). 24. H. Lee, X. Ren, C. Niu, L. Yu, M. H. Engelhard, I. Cho, M. H. Ryou, H. S. Jin, H. T. Kim and J. Liu, Suppressing lithium dendrite growth by metallic coating on a separator, Advanced Functional Materials 27, , (2017). 25. W. Luo, L. Zhou, K. Fu, Z. Yang, J. Wan, M. Manno, Y. Yao, H. Zhu, B. Yang and L. Hu, A thermally conductive separator for stable Li metal anodes, Nano letters 15, , (2015). 26. J. Park, J. Jeong, Y. Lee, M. Oh, M. H. Ryou and Y. M. Lee, Micro-patterned lithium metal anodes with suppressed dendrite formation for post lithium-ion batteries, Advanced Materials Interfaces 3, , (2016). 27. S. Kim, J. Park, A. Friesen, H. Lee, Y. M. Lee and M.- H. Ryou, Composite protection layers for dendritesuppressing non-granular micro-patterned lithium metal anodes, Electrochimica Acta 282, , (2018). 28. J. Heine, S. Krüger, C. Hartnig, U. Wietelmann, M. Winter and P. Bieker, Coated Lithium Powder (CLiP) Electrodes for Lithium-Metal Batteries, Advanced Energy Materials 4, , (2014). 29. M. H. Ryou, Y. M. Lee, Y. Lee, M. Winter and P. Bieker, Mechanical surface modification of lithium metal: towards improved Li metal anode performance by directed Li plating, Advanced Energy Materials 25, , (2015). 30. D. Jin, J. Oh, A. Friesen, K. Kim, T. Jo, Y. M. Lee and M.-H. Ryou, Self-Healing Wide and Thin Li Metal Anodes Prepared Using Calendared Li Metal Powder for Improving Cycle Life and Rate Capability, ACS applied materials & interfaces 10, , (2018). 31. J. Park, D. Kim, D. Jin, C. Phatak, K. Y. Cho, Y.-G. Lee, S. Hong, M.-H. Ryou and Y. M. Lee, Size effects of micro-pattern on lithium metal surface on the electrochemical performance of lithium metal secondary batteries, Journal of power sources 408, , (2018). 32. Y. J. Kim, H. S. Jin, D. H. Lee, J. Choi, W. Jo, H. Noh, J. Lee, H. Chu, H. Kwack and F. Ye, Guided Lithium Deposition by Surface Micro-Patterning of Lithium- Metal Electrodes, ChemElectroChem 5, , (2018). 33. K. N. Wood, M. Noked and N. P. Dasgupta, Lithium metal anodes: toward an improved understanding of coupled morphological, electrochemical, and mechanical behavior, ACS Energy Letters 2, , (2017). 34. W. Li, H. Zheng, G. Chu, F. Luo, J. Zheng, D. Xiao, X. Li, L. Gu, H. Li and X. Wei, Effect of electrochemical dissolution and deposition order on lithium dendrite formation: a top view investigation, Faraday discussions 176, , (2015). 35. K. Abe, H. Yoshitake, T. Kitakura, T. Hattori, H. Wang and M. Yoshio, Additives-containing functional electrolytes for suppressing electrolyte decomposition in lithium-ion batteries, Electrochimica Acta 49, , (2004). 36. J. Guo, Z. Wen, M. Wu, J. Jin and Y. J. E. C. Liu, Vinylene carbonate LiNO3: A hybrid additive in carbonic ester electrolytes for SEI modification on Li metal anode, Electrochemistry Communications 51, 59-63, (2015). 37. X.-G. Sun and S. Dai, Electrochemical investigations of ionic liquids with vinylene carbonate for applications in rechargeable lithium ion batteries, Electrochimica Acta 55, , (2010). 38. I. A. Profatilova, C. Stock, A. Schmitz, S. Passerini and M. Winter, Enhanced thermal stability of a lithiated nano-silicon electrode by fluoroethylene carbonate and vinylene carbonate, Journal of power sources 222, , (2013). 39. D. Xiong, J. Burns, A. Smith, N. Sinha and J. Dahn, A high precision study of the effect of vinylene carbonate (VC) additive in Li/graphite cells, Journal of The Electrochemical Society 158, A1431-A1435, (2011). 40. X. Q. Zhang, X. B. Cheng, X. Chen, C. Yan and Q. Zhang, Fluoroethylene carbonate additives to render uniform Li deposits in lithium metal batteries, Advanced Functional Materials 27, , (2017). 41. M.-H. Ryou, G.-B. Han, Y. M. Lee, J.-N. Lee, D. J. Lee, Y. O. Yoon and J.-K. Park, Effect of fluoroethylene carbonate on high temperature capacity retention of LiMn2O4/graphite Li-ion cells, Electrochimica Acta 55, , (2010). 42. J. Heine, P. Hilbig, X. Qi, P. Niehoff, M. Winter and P. Bieker, Fluoroethylene carbonate as electrolyte additive in tetraethylene glycol dimethyl ether based electrolytes for application in lithium ion and lithium metal batteries, Journal of The Electrochemical Society 162, A1094- A1101, (2015). 43. J.-H. Song, J.-T. Yeon, J.-Y. Jang, J.-G. Han, S.-M. Lee and N.-S. Choi, Effect of fluoroethylene carbonate on electrochemical performances of lithium electrodes and lithium-sulfur batteries, Journal of The Electrochemical Society 160, A873-A881, (2013). 44. E. Markevich, G. Salitra, F. Chesneau, M. Schmidt and D. Aurbach, Very stable lithium metal stripping plating at a high rate and high areal capacity in fluoroethylene carbonate-based organic electrolyte solution, ACS Energy Letters 2, , (2017). 45. G.-B. Han, J.-N. Lee, D. J. Lee, H. Lee, J. Song, H. Lee, M.-H. Ryou, J.-K. Park and Y. M. Lee, Enhanced cycling performance of lithium metal secondary batteries with succinic anhydride as an electrolyte additive, Electrochimica Acta 115, , (2014). 46. M.-H. Ryou, J.-N. Lee, D. J. Lee, W.-K. Kim, J. W. Choi, J.-K. Park and Y. M. Lee, 2-(triphenylphosphoranylidene) succinic anhydride as a new electrolyte additive to improve high temperature cycle performance of LiMn2O4/graphite Li-ion batteries, Electrochimica Acta 102, , (2013). 47. Y. Li, G. Xu, Y. Yao, L. Xue, S. Zhang, Y. Lu, O.

10 78 J. Korean Electrochem. Soc., Vol. 22, No. 2, 2019 Toprakci and X. Zhang, Improvement of cyclability of silicon-containing carbon nanofiber anodes for lithiumion batteries by employing succinic anhydride as an electrolyte additive, Journal of Solid State Electrochemistry 17, , (2013). 48. J. Jeong, J.-N. Lee, J.-K. Park, M.-H. Ryou and Y. M. Lee, Stabilizing effect of 2-(triphenylphosphoranylidene) succinic anhydride as electrolyte additive on the lithium metal of lithium metal secondary batteries, Electrochimica Acta 170, , (2015). 49. L. El Ouatani, R. Dedryvere, C. Siret, P. Biensan, S. Reynaud, P. Iratçabal and D. Gonbeau, The effect of vinylene carbonate additive on surface film formation on both electrodes in Li-ion batteries, Journal of The Electrochemical Society 156, A103-A113, (2009). 50. Y. Wang, S. Nakamura, K. Tasaki and P. B. Balbuena, Theoretical studies to understand surface chemistry on carbon anodes for lithium-ion batteries: how does vinylene carbonate play its role as an electrolyte additive?, Journal of the American Chemical Society 124, , (2002). 51. C. C. Nguyen and B. L. Lucht, Comparative study of fluoroethylene carbonate and vinylene carbonate for silicon anodes in lithium ion batteries, Chemistry of Materials 161, A1933-A1938, (2014). 52. F. A. Soto, Y. Ma, J. M. Martinez de la Hoz, J. M. Seminario and P. B. Balbuena, Formation and growth mechanisms of solid-electrolyte interphase layers in rechargeable batteries, Chemistry of Materials 27, , (2015). 53. A. L. Michan, B. S. Parimalam, M. Leskes, R. N. Kerber, T. Yoon, C. P. Grey and B. L. Lucht, Fluoroethylene carbonate and vinylene carbonate reduction: understanding lithium-ion battery electrolyte additives and solid electrolyte interphase formation, Chemistry of Materials 28, , (2016). 54. X. Zhang, R. Kostecki, T. J. Richardson, J. K. Pugh and P. N. Ross, Electrochemical and infrared studies of the reduction of organic carbonates, Journal of The Electrochemical Society 148, A1341-A1345, (2001). 55. Y.-K. Han, Y. Moon, K. Lee and Y. S. Huh, Computational screening of lactam molecules as solid electrolyte interphase forming additives in lithium-ion batteries, Current Applied Physics 14, , (2014).

한국전지학회 춘계학술대회 Contents 기조강연 LI GU 06 초강연 김동욱 09 안재평 10 정창훈 11 이규태 12 문준영 13 한병찬 14 최원창 15 박철호 16 안동준 17 최남순 18 김일태 19 포스터 강준섭 23 윤영준 24 도수정 25 강준희 26

한국전지학회 춘계학술대회 Contents 기조강연 LI GU 06 초강연 김동욱 09 안재평 10 정창훈 11 이규태 12 문준영 13 한병찬 14 최원창 15 박철호 16 안동준 17 최남순 18 김일태 19 포스터 강준섭 23 윤영준 24 도수정 25 강준희 26 2015 한국전지학회 춘계학술대회 2일차 한국전지학회 춘계 학술대회(신소재 및 시장동향 관련 주제 발표) 시간 제목 비고 세션 1 차세대 이차전지용 in-situ 분석기술 좌장 : 윤성훈 09:00~09:30 Real-time & Quantitative Analysis of Li-air Battery Materials by In-situ DEMS 김동욱(한국화학연구원)