특별초청 세미나
미래를 창조하는 포스텍 화학공학과
Towardscontrolling of Li2O2 structures for improvement ofcharging over…
- 일자
- 2017.08.21(월)
- 시간
- 17:00~
- 연사
- 변혜령 교수
- 장소
- 환경공학동 111호
- 소속
- KAIST 화학과
The rechargeablelithium-oxygen (Li-O2) battery, providing theoretically highspecific-energy-density calculated as ~3 kWh kg-1cell, isa promising future energy storage system. However, the over-potential isconsiderably severe during charge due to difficulty of Li2O2decomposition (Li2O2(s) à 2Li+ + O2(g) + 2e−, Erev = 2.96 V vs. Li+/Li),which is one of the greatest challenges for implementation of practical batterysystems. Much effort has been devoted by incorporation of metal oxide promotersand soluble redox mediator. However, these additive materials give rise to moreside reactions and require high cost. Here I present the new strategy of Li2O2structural engineering to reduce the charge over-potential. The design ofelectrode surface can enhance adsorption affinity of O2 and LiO2,which determines morphology and structure of Li2O2. Wefound that the resulting amorphous Li2O2 facilelydecomposes in comparison with crystal structure, which is attributed toincreased ionic and electronic conductivity of Li2O2.