ИСТИНА

Lithium-oxygen chemistry can potentially enable development of rechargeable batteries demonstrating a few-fold increased specific energy in comparison to lithium-ion ones. The practical implementation of this idea, however, faces a number of significant challenges. The first one is the problem of positive electrode material stability during cycling. During lithium-air battery (LAB) operation oxygen reduction reaction occurs at the positive electrode – oxygen dissolved in the electrolyte is reduced to superoxide (O2-), which forms ionic pairs with Li+ (LiO2). Such intermediates are then converted to a final discharge product lithium peroxide (Li2O2) after transfer of second electron from the electrode or by chemical disproportionation reaction. Unfortunately, oxygen reduction products and intermediates are highly reactive species that can attack both electrolyte solvents and electrode materials. Among others, carbon materials received major attention as a positive electrode in Li–O2 cells as they are freely available, porous, highly conductive and lightweight. The requirements for porous positive electrodes and their chemical stability would be discussed in the talk using carbon materials and Ti-based conductive compounds as an examples. Issues connected with negative electrode, namely SEI formation on metallic lithium electrodes and dendrite growth would be also considered. Application of a number of neutron and synchrotron-based tools (SANS, neutron reflectometry, XPS/NAP XPS and others) for monitoring the interfacial processes at both negative and positive electrodes will be demonstrated.