Advanced Materials for Na-Air Batteries

摘要

9.1 INTRODUCTION As the amount of fossil fuels decreases worldwide together with the issue of global warming, it becomes necessary to develop clean and renewable energy storage and conversion systems for transportation. Lithium-ion batteries (LIBs) are promising alternatives to the internal combustion engine for hybrid electric vehicles, plug-in hybrid electric vehicles, and pure electric vehicles. However, the energy density of current LIBs is limited by the intercalation chemistry occurring within the electrode materials, which will not meet the rapid growth of energy demand for future electric vehicle applications. Lithium-air batteries have been intensively studied during the last few years, and they have shown extremely high discharge capacities [1-3]. They consist of a lithium metal anode, a liquid electrolyte comprising lithium salts dissolved in organic solvents, a micro-porous polymer separator, and a porous cathode electrode. The theoretical energy density of lithium-air battery is about 3600 Wh kg~(-1), which is eight times that of LIBs. Moreover, the batteries could be charged when electrocatalysts that facilitate the oxygen evolution reaction (OER) are applied in cathodes.