This work deals with core issues of Li–oxygen battery systems; intrinsic stability of polyether electrolyte solutions and the role of important redox mediators such as LiI/I2.

Improved efficiency and cyclability of cells containing LiBr demonstrate that the appropriate choice of electrolyte solution is the key to a successful Li–O2 battery.

Non-aqueous, rechargeable battery development is one of the most important challenges of modern electrochemistry. Li ion batteries are a commercial reality for portable electronics with intensive efforts underway to apply this technology to electro-mobility. Extensive investigations of high energy density Li-sulfur and Li-oxygen systems have also been carried-out. Efforts to promote high energy density power sources for electric vehicles have been accompanied by intensive work on the development of rechargeable sodium and magnesium batteries for load-leveling applications. The electrolyte solution is a key consideration in all batteries determining cell stability, cycle life, and safety. This review discusses the importance of solution selection for advanced, high-voltage, Li ion batteries, sodium ion batteries, as well as Li-sulfur, Li-oxygen and magnesium batteries. Li ion battery standard solutions are discussed and their further optimization is outlined. Limitations of Li metal electrodes are explained. Unique problems in the use of conventional non-aqueous solutions for Li-oxygen batteries, related to intrinsic stability, are delineated. Finally, electrolyte solutions for Mg batteries are briefly reviewed, concluding that only the relatively inert ethereal solutions are suitable for future consideration. Several systems exhibit wide electrochemical windows and reversible behavior with Mg anodes, however compatibility with high-voltage/high-capacity cathodes remains a major challenge.It is impossible to imagine modern society without electrochemical power sources. The electronic revolution relies heavily on the use of highly sophisticated portable devices -including cellular phones with amazing applications, laptops, video cameras and more. All this advancement depends on the availability of high-energy density, safe and cost-effective power sources. The challenge of discovering rechargeable power sources has increased markedly in recent years, spurred by the demand for electro-mobility to replace propulsion by fossil fuels that have traditionally powered internal combustion engines.Challenges such as electrochemical propulsion by electric vehicles (EV), and the need for large-scale storage of sustainable energy (i.e. load-levelling applications) have motivated and stimulated the development of novel rechargeable batteries and super-capacitors. Batteries deliver high energy density, but have only limited cycle life and power density; super-capacitors, on the other hand, provide high power density and very prolonged cycling. Lithium-ion batteries are the focus of intensive R&D (research and development) efforts because they promise high energy density that may be suitable for electrical propulsion. Batteries (especially those like Li ion batteries with high energy density) are exceedingly complicated devices: three active bulks and two active interfaces must function simultaneously without side reactions or detrimental reflections.Consequently, R&D of novel battery systems requires investing time and effort in...

Pairing lithium and oxygen in aprotic solvents can theoretically lead to one of the most promising electrochemical cells available. If successful, this system could compete with technologies such as the internal combustion engine and provide an energy density that can accommodate electric vehicle demands. However, there are many problems that have inhibited this technology from becoming realistic. One of the main reasons is capacity fading after only a few cycles, which is caused by the instability of electrolyte solutions in the presence of reduced oxygen species like O2.− and O22−. In recent years, using various analytical tools, researchers have been able to isolate the breakdown products arising from the reactions occurring between the aprotic solvent and the reduced oxygen species. Nevertheless, no solvents have yet been found that are fully stable throughout the reduction and oxidation processes. However, an understanding of these decomposition mechanisms can help us in designing new systems that are more stable toward the aggressive conditions taking place in LiO2 cell operation. This review will include analytical studies on the most widely used solvents in current LiO2 research.