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.