123rd General Meeting of the KCS

Type Symposium
Area Physical Chemistry Approaches in Energy and Environmental Materials
Room No. Room 401+402
Time FRI 15:20-15:40
Code PHYS3-3
Subject Towards controlling of Li2O2 structures for improvement of charging overpotential in lithium-oxygen batteries
Authors Hye Ryung Byon
Department of Chemistry, Korea Advanced Institute of Science and Technology, Korea
Abstract The rechargeable lithium-oxygen (Li-O2) battery, providing theoretically high specific-energy-density calculated as ~3 kWh kg-1cell, is a promising future energy storage system. However, the over-potential is considerably severe during charge due to difficulty of Li2O2 decomposition (Li2O2(s) --> 2Li+ + O2(g) + 2e, Erev = 2.96 V vs. Li+/Li), which is one of the greatest challenges for implementation of practical battery systems. Much effort has been devoted by incorporation of metal oxide promoters and soluble redox mediator. However, these additive materials give rise to more side reactions and require high cost. Here I present the new strategy of Li2O2 structural engineering to reduce the charge over-potential. The design of electrode surface can enhance adsorption affinity of O2 and LiO2, which determines morphology and structure of Li2O2. We found that the resulting amorphous Li2O2 facilely decomposes in comparison with crystal structure, which is attributed to increased ionic and electronic conductivity of Li2O2.
E-mail hrbyon@kaist.ac.kr