Research progress and the limiting factors that affect performance of the lithium air batteries

Lithium air battery has attracted extensive attention due to its potential in achieving much higher practical specific energy than existing batteries, and it may become one of the most promising next generation battery technologies. Lithium air battery has the compelling advantage of theoretical specific energy, i.e. 3622 Wh•kg^-1 (assuming Li₂O₂ is the product), which is attributed to the use of a lithium metal anode and the ready availability of the cathode oxidant, i.e. oxygen, from the surrounding air. Other advantages include stable potentials, high safety, low cost, friendly to environment. However, before Lithium air batteries can be commercialized, the following challenges still need to be overcome: optimization of the cathode materials structure and the electrolyte composition, enhancement of the actual discharge special capacity, and improvement of the cycle performance and elucidating the reaction mechanism that occurs during charge and discharge. In this paper, we presented the current research progress and the limiting factors that affect performance of the batteries, such as microcomposition and microstructure of the cathode materials, constitution of the electrolytes, oxygen selective membranes, the structure design for the lithium air batteries, charge and discharge mechanism; compared lithium air battery with other advanced batteries, i.e. lithium air battery, lithium ion battery, lead-acid battery, nickel-hydride battery and fuel cells electrochemical properties, such as specific capacity, specific energy, specific power and open circuit voltage; summarized the effect of the composition and structure of the cathode materials on its performance; discussed the merits and demerits of aqueous electrolyte, non-aqueous electrolyte and dual-electrolyte for Li-air batteries; analyzed the effect of solubility coefficient, conductivity and viscosity of various components non-aqueous electrolytes, established the heterogeneous reaction model of cathode in organic electrolyte and aqueous electrolyte and reviewed state-of-the-art characterization techniques of the materials for lithium air batteries and the application prospect of lithium air battery.