Gas concentration-driven LiOH chemistry in Li-CO2 batteries

Abstract

In conventional Li-CO2 batteries, Li2CO3 is an intractable discharge product due to its wide bandgap. To this end, researchers have focused more attention on the decomposition of Li2CO3 in order to reduce the high charge potential. However, even the kinetics of CO2 evolution process can be accelerated, Li2CO3 will still passivate the cathodes, which in turn affects the cycle life of Li-CO2 batteries. Here, we designed a CO2 partly-absent Li-CO2 battery, the concentration of CO2 involved during the discharge process is reduced, then the discharge potential of this battery can be moved to 2.1 V. Furthermore, the discharge product of this CO2 partly-absent Li-CO2 battery is proved to be LiOH instead of Li2CO3, it can be recharged at a low potential of 3.5 V benefit from the readily degradable product (LiOH). In this Li-CO2 battery, the effect of gas concentration on discharge process is studied firstly, and totally different results are discussed, offering new insights into the material design and the development of reliable rechargeable Li-CO2 batteries in the future.