The chemistries based on the Li-O₂ couple in aprotic electrolyte seem promising to provide ultrahigh-energy density values and outperform the current LIB technology. The main targeted application is to power electrified vehicles, with the hope of achieving high driving range. Unfortunately, serious side-reaction issues have plagued their development for practical applications so far. For example, during the discharge process, undesired insulating products are formed instead of lithium peroxide. Moreover, the blocking/clogging effect on the air electrode due to a deposition process leads to an overpotential during both the discharge (Oxygen Reduction Reaction: ORR) and charge processes (Oxygen Evolution Reaction: OER), which results in electrode degradation, electrolyte decomposition and precocious cell failure.

A promising strategy to reduce these overpotentials is the use of organic redox mediators by taking advantage of their tunability. For several years, our group has been developing lithiated organic materials with average redox potentials close to the O₂/Li₂O₂ redox couple (2.96 V vs Li⁺/Li⁰). We here report the effect of Li₂DAnT (alone or in combination with Li₄-p-DHT [1]) and Li₄-DHNDC [2] on the cycling behavior of Li-O₂ batteries and their influence on ORR and OER processes.

References

1) S. Renault, et al., PCT Patent WO 2021/148835 A1.

2) S. Renault, et al., PCT Patent WO 2021/148836 A1.