Li2CO3-free Li–O2/CO2 battery with peroxide discharge product

Abstract

Owing to the exceptionally high energy potential of lithium–oxygen chemistry, lithium–air batteries have received much attention as appealing alternatives to current state-of-art lithium ion batteries. However, owing to the presence of non-O₂ components in ambient air, the practical performance of Li–air batteries is limited to only a few cycles with low energy efficiency. In particular, when CO₂ is incorporated into the battery system, Li₂CO₃ is formed during discharging, which results in serious climbing of the charge potential and subsequent decomposition of the cell components. Herein, by introducing an appropriate electrolyte into an aggregated contact ion pair (CIP) structure, we demonstrate a Li–O₂/CO₂ battery, via formation of stabilized peroxodicarbonate (C₂O₆²⁻) rather than Li₂CO₃ in the electrolyte, that operates with a very low charge potential (3.5 V). We anticipate that this discovery will provide a rational design strategy for modifying the reaction pathway of Li–O₂/CO₂ battery and accelerating the evolution of Li–O₂ batteries to Li–air batteries.