Development of a rechargeable lithium-air battery with very high energy density – LiO2

The development of Lithium-air batteries represents an important breakthrough in batteries because for the first time an all electric vehicle with a range comparable to the traditional petrol driven ICE (> 500 km) car can be envisaged without recharging. A preliminary project of short duration (ANR funded project “LIO”) demonstrated the feasibility of the aqueous lithium-air concept in which the product of the reaction is stored in the aqueous electrolyte as a precipitate and not in the porosity of the air electrode as is done in the anhydrous Li-air concept.

The objective of the project LiO2 is to remove the barriers which have been identified in the LIO project, to enable the Li-air technology to reach a new phase towards the development of a high range electric car. In order to do so, LiO2 aims to increase the current density to 50 mA/cm², to increase the number of cycles to more than 100 initially and to increase the capacity to 200 mA/cm² of electrode. Finally, the demonstration of the progress achieved will be demonstrated in a 5 cell battery using ambient untreated air and with the following performance :

–2 Ah, 15V, 30 Wh
–200 mAh/cm², 10 cm²
–C/10
–100 cycles
To reach these goals, the LiO2 project will develop new Li+ conducting ceramics which are stable in contact with Li metal. New ceramic membranes will be produced in order to have a barrier to air and water which is sufficiently thin to not enable high current densities. These thin electrolytes will be reinforced with a mechanical support. Several ceramic processing techniques to produce these membranes will be compared such as Spark Plasma Sintering, Tape Casting or Slip Casting.

New anionic polymer membranes will be developed which are more stable by using interpenetrating networks of polymers. These membranes will be used to protect the air electrode from CO2 and LiOH precipitation inside the electrode.

A novel reversible air electrode will be developed which will be stable to oxygen evolution

Finally, the growth of lithium metal on an ironically conducting solid ceramic surface will be studied by using in-situ techniques. These studies will be important to understand the cyclability of lithium metal on solid material with a transport number = 1. The results of these studies will be used to develop new interface layers with lithium