Failure analysis of pouch-type Li-O-2 batteries with superior energy density

Li-O-2 batteries have attracted significant interest in the past decade owing to their superior high specific energy density in contrast to conventional lithium ion batteries. An 8.7-Ah Li-O-2 pouch cell with 768.5 Wh kg(-1) was fabricated and characterized in this investigation and the factors that influenced the electrochemical performance of the Li-O-2 pouch cell were studied. In contrast to coin/Swagelok-type Li-O-2 cells, it was demonstrated that the high-loading air electrode, pulverization of the Li anode, and the large-scale inhomogeneity of the large pouch cell are the major reasons for the failure of Li-O-2 batteries with Ah capacities. In addition, safety tests of large Li-O-2 pouch cells were conducted for the first time, including nail penetration, crushing, and thermal stability. It was indicated that a self-limiting mechanism is a key safety feature of these batteries, even when shorted. In this study, Li-O-2 batteries were investigated in a new size and capacity-scale, which may provide useful insight into the development of practical pouch-type Li-O-2 batteries. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.