표면 피막 형성이 LiCoO2 양극의 고온 열화에 미치는 영향
Accelerated Formation of Surface Films on the Degradation of LiCoO2 Cathode at High Temperature
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리튬이온전지의 열적 열화 메커니즘을 이해하는 것은 전지의 안전성을 향상시키기 위한 필수적인과정이다. 본 논문에서는 대표적인 양극물질의 하나인 리튬코발트산화물(LiCoO2, LCO)이 고온에서 작동할 때 형성되는 표면 필름에 의한 전기화학적 성능 열화를 조사하였다. 먼저 25oC와60oC 각각의 온도에서 사이클 테스트를 진행한 결과, 60oC에서 25oC에 비해 저하된 사이클 수명을 보였다. 이후 처음 5사이클을 25oC, 60oC에서 구동시킨 LCO 양극을 각각 25-LCO, 60- LCO라 명명하였으며, 이후 임피던스 및 출력 특성 분석은 25oC에서 진행하였다. 이때 두 샘플모두 저속에서의 초기 용량은 비슷함에도 불구하고 60-LCO가 25-LCO에 비해 높은 임피던스와낮은 출력 특성을 보였다. X-선 광전자분광 (XPS)분석 결과 60-LCO 샘플에서 cathodeelectrolyte interphase의 성분 중 하나인 절연성의 수산화 리튬 (LiOH) 성분이 다량 검출되었으며, 이는 고온에서 과도한 표면 필름 형성이 양극의 표면 저항 증가 및 속도/수명 특성 저하를가져왔음을 보여준다.
Abstract
It is crucial to investigate the thermal degradation of lithium-ion batteries (LIBs) to understand the possible malfunction at high temperature. Herein, we investigated the effects of surface film formation on the thermal degradation of lithium cobalt oxide (LiCoO2, LCO) cathode that is one of representative cathode materials. Cycling test at 60oC exhibited poorer cycleability compared with the cycling at 25oC. Cathodes after the initial 5 cycles at 60oC (60-LCO) exhibited higher impedance compared to the cathode after initial 5 cycles at 25oC (25-LCO), resulting in the lower rate capability upon subsequent cycling at 25oC, although the capacity values were similar at the lowest C-rate of 0.1C. In order to understand degradation of the LCO cathode at the high temperature, we analyzed the cathodes surface using X-ray photoelectron spectroscopy (XPS). Among various peaks, intensity of lithium hydroxide (LiOH) increased substantially after the operation at 60oC, and the C-C signal that represents the conductive agent was distinctly lower on 60-LCO compared to 25-LCO. These results pointed to an excessive formation of cathode-electrolyte interphase including LiOH at 60oC, leading to the increase in the resistance and the resultant degradation in the electrochemical performances.
참고문헌 (41)
- Y. Nishi, "Lithium ion secondary batteries; past 10 years and the future", J. Power Sources, 100, pp.101~ (2001)
- J. -Y. Hwang, "Sodium-ion batteries: present and future", Chem. Soc. Rev, 46, pp.3529~ (2017)
- J. Zheng, "Effect of calcination temperature on the electrochemical properties of nickel-rich LiNi0.76Mn0.14Co0.10O2 cathodes for lithium-ion batteries", Nano Energy, 49, pp.538~ (2018)
- W. Cho, "Facile Mn surface doping of Ni-rich layered cathode materials for lithium ion batteries", ACS Appl. Mater. Interfaces, 10, pp.38915~ (2018)
- L. Zhu, "LiFePO4-Coated LiNi0.5Co0.2Mn0.3O2 Cathode Materials with Improved High Voltage Electrochemical Performance and Enhanced Safety for Lithium Ion Pouch Cells", J. Electrochem. Soc, 166, pp.A5437~ (2019)
- Z. Wu, "Carbon Nanomaterial Based Flexible Batteries for Wearable Electronics", Adv. Mater, 31, pp.1800716~ (2019)
- Y. Park, "Investigation of solid electrolyte interface (SEI) film on LiCoO2 cathode in fluoroethylene carbonate (FEC)-containing electrolyte by 2D correlation X-ray photoelectron spectroscopy (XPS)", J. Mol. Struct, 1069, pp.157~ (2014)
- F. Zheng, "Review on solid electrolytes for all-solid-state lithiumion batteries", J. Power Sources, 389, pp.198~ (2018)
- J. B. Goodenough, "Challenges for rechargeable Li batteries", Chem. Mater, 22, pp.587~ (2009)
- V. Etacheri, "Challenges in the development of advanced Li-ion batteries: a review", Energy Environ. Sci, 4, pp.3243~ (2011)
- D. H. Doughty, "A general discussion of Li ion battery safety", Electrochem. Soc. Interface, 21, pp.37~ (2012)
- L. Lu, "A review on the key issues for lithium-ion battery management in electric vehicles", J. Power Sources, 226, pp.272~ (2013)
- P. Balakrishnan, "Safety mechanisms in lithium-ion batteries", J. Power Sources, 155, pp.401~ (2006)
- A. Jansen, "Development of a high-power lithium-ion battery", J. Power Sources, 81, pp.902~ (1999)
- K. Liu, "Materials for lithium-ion battery safety", Sci. Adv, 4, pp.eaas9820~ (2018)
- K. Mizushima, "LixCoO2 (0<x<1): A new cathode material for batteries of high energy density", Mater. Res. Bull, 15, pp.783~ (1980)
- L. Dahéron, "Possible Explanation for the Efficiency of Al-Based Coatings on LiCoO2: Surface Properties of LiCo1−xAlxO2 Solid Solution", Chem. Mater, 21, pp.5607~ (2009)
- Y. -C. Lu, "Probing the origin of enhanced stability of “AlPO4” nanoparticle coated LiCoO2 during cycling to high voltages: combined XRD and XPS studies", Chem. Mater, 21, pp.4408~ (2009)
- J. Cho, "LiCoO2 cathode material that does not show a phase transition from hexagonal to monoclinic phase", J. Electrochem. Soc, 148, pp.A1110~ (2001)
- J. N. Reimers, "Electrochemical and in situ X-ray diffraction studies of lithium intercalation in Lix-CoO2", J. Electrochem. Soc, 139, pp.2091~ (1992)
- G. Amatucci, "CoO2, the end member of the LixCoO2 solid solution", J. Electrochem. Soc, 143, pp.1114~ (1996)
- J. -N. Zhang, "Dynamic evolution of cathode electrolyte interphase (CEI) on high voltage LiCoO2 cathode and its interaction with Li anode", Energy Storage Materials, 14, pp.1~ (2018)
- A. Yano, "LiCoO2 degradation behavior in the high-voltage phase transition region and improved reversibility with surface coating", J. Electrochem. Soc, 164, pp.A6116~ (2017)
- S. -T. Myung, "Effects of Al doping on the microstructure of LiCoO2cathode materials", Solid State Ionics, 139, pp.47~ (2001)
- M. Zou, "Synthesis of high-voltage (4.5 V) cycling doped LiCoO2for use in lithium rechargeable cells", Chem. Mater, 15, pp.4699~ (2003)
- A. Liu, "Synthesis of Mg and Mn Doped LiCoO2 and Effects on High Voltage Cycling", J. Electrochem. Soc, 164, pp.A1655~ (2017)
- C. Hudaya, "SnO2-coated LiCoO2 cathode material for high-voltage applications in lithium-ion batterie", Solid State Ionics, 256, pp.89~ (2014)
- A. Zhou, "Sputtering TiO2 on LiCoO2 composite electrodes as a simple and effective coating to enhance high-voltage cathode performance", J. Power Sources, 346, pp.24~ (2017)
- B. Hwang, "Mechanism study of enhanced electrochemical performance of ZrO2-coated LiCoO2 in high voltage region", J. Power Sources, 195, pp.4255~ (2010)
- S. Oh, "Effect of Al2O3 coating on electrochemical performance of LiCoO2 as cathode materials for secondary lithium batteries", J. Power Sources, 132, pp.249~ (2004)
- 장윤한, "리튬이차전지용 양극 활물질(LiCoO2)의 표면처리의 특성 분석 및 전기화학적 특성 고찰", 전기화학회지, 10(3), pp.184~189 (2007), 한국전기화학회
- H. Wang, "Effect of LiFePO4 coating on electrochemical performance of LiCoO2 at high temperature", Solid State Ionics, 178, pp.131~ (2007)
- A. Zhou, "Improved high-voltage and high-temperature electrochemical performances of LiCoO2 cathode by electrode sputter-coating with Li3PO4", J. Power Sources, 322, pp.10~ (2016)
- X. Zhu, "Enhanced electrochemical performance of Mg-doped LiCoO2 synthesized by a polymer-pyrolysis method", Ceram. Int, 40, pp.11245~ (2014)
- Z. Wang, "Mg doping and zirconium oxyfluoride coating co-modification to enhance the high-voltage performance of LiCoO2 for lithium ion battery", J. Alloys Compd, 621, pp.212~ (2015)
- J. Fu, "Electrochemical properties of the LiNi0.6Co0.2Mn0.2O2 cathode material modified by lithium tungstate under high voltage", ACS Appl. Mater. Interfaces, 10, pp.19704~ (2018)
- P. Elumalai, "A note on overpotential dependence of AC impedance data", J. Solid State Electrochem, 3, pp.470~ (1999)
- J. Kim, "Controllable Solid Electrolyte Interphase in Nickel-Rich Cathodes by an Electrochemical Rearrangement for Stable Lithium-Ion Batteries", Adv. Mater, 30, pp.1704309~ (2018)
- Z. W. Lebens-Higgins, "Evolution of the Electrode–Electrolyte Interface of LiNi0.8Co0.15Al0.05O2 Electrodes Due to Electrochemical and Thermal Stress", Chem. Mater, 30, pp.958~ (2018)
- S. Verdier, "XPS study on Al2O3-and AlPO4-coated LiCoO2 cathode material for high-capacity Li ion batteries", J. Electrochem. Soc, 154, pp.A1088~ (2007)
- J. Chen, "LiNi0.8Co0.15Al0.05O2cathodes exhibiting improved capacity retention and thermal stability due to a lithium iron phosphate coating", Electrochim. Acta, 312, pp.179~ (2019)