Toward rechargeable lithium–oxygen batteries: recent advances

Abstract

Toward rechargeable Li–O2 batteries: recent advances Nobuyuki Imanishi Department of Chemistry, Mie University, Tsu, Mie, Japan Abstract: This review summarizes research and development trends in lithium–oxygen (Li–O2) batteries. Development of a post–lithium-ion battery is highly expected to be a means to solve the global energy problem. The metal–oxygen cell, especially the Li–O2 cell, attracts attention, since it has much larger theoretical energy density than conventional battery systems. First, this review discusses the energy density that a battery should have from the viewpoint of power sources for electric vehicles. Then the fundamental features of various kinds of metal–oxygen batteries are explained and challenges faced by them are described. The remaining part of the review focuses on research subjects of the Li–O2 batteries. Early works which led to the present lithium–oxygen cells are briefly presented. Then, systems using various electrolytes and their major issues are introduced. First, irreversible decomposition of the electrolyte and Li2O2 deposition at oxygen cathode of an organic system are described. The effort that is directed toward the solution of dendritic growth of lithium metal anode is also introduced. Thereafter, new materials, mechanisms, and strategy that were reported recently are described with regard to each of the three electrolyte systems, respectively. These are expected to be breakthroughs to solve the serious problems, such as irreversible decomposition of electrolyte. In conclusion, the issues that should be solved with the direction of future development are mentioned.Keywords: energy density, lithium anode, dendrite, peroxide, superoxide