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  • 09월 11일 00시 이후 : 초록수정 불가능, 일정확인 및 검색만 가능

제124회 대한화학회 학술발표회, 총회 및 기기전시회 안내 In situ observation of Li–O2 electrochemical reactions using electrochemical atomic force microscopy

2019년 8월 22일 20시 21분 28초
ANAL2-3 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
목 16시 : 40분
Analytical Chemistry - Advanced In-situ/Operando Analysis for Energy and Environmental Applications
저자 및
Hye Ryung Byon
Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea
Despite more than 3 times higher theoretical energy density than that of lithium-ion batteries, lithium–oxygen (Li–O2 ) batteries have not yet been used in practical applications due to a significant overpotential required for charging process (Li2 O2 (s) → 2Li+ + O2 + 2e on the positive electrode). The formation and decomposition of Li2 O2 take place during discharging and charging process, respectively, while these reactions are very sluggish due to poor electronic and ionic conductivities of Li2 O2. In particular, Li2 O2 decomposition process is a key hurdle for improving round-trip efficiency in Li–O2 batteries, which was not clearly addressed. Here I show in-situ imaging of Li–O2 redox reaction on highly oriented pyrolytic graphite (HOPG) electrode in ether-based electrolyte using electrochemical atomic force microscopy (ECAFM). For discharging, a thin film of Li2 O2 with ~ 3 nm of thickness is deposited from edge planes of HOPG. For charging, the film decomposes at the local thinner part by ~3.7 V (vs. Li/Li+), followed by full decomposition over 4.2 V. In comparison with such a sluggish decomposition process, the effect of redox mediator that promotes anodic behavior of Li2 O2 is also demonstrated using ECAFM.