H₂O wash: a simple method toward eliminating discharge products and regenerating cathodes of Li-O₂ batteries

The development of air cathodes for Li-O₂ batteries is extensively studied, but focus on recycling Li-O₂ batteries is still limited. Usually, the final death of Li-O₂ batteries is caused by the accumulation of discharge products (Li₂O₂) on air cathodes which cannot be decomposed. Herein, we report an H₂O-wash method that could regenerate air cathodes and pretreat them for air-cathode characterization. We successfully regenerated two kinds of air cathodes for at least five rounds without capacity fading. The structural and chemical/electrochemical changes of air cathodes could be easily observed owing to the removal of discharge products. Volume expansion and functionalized carbon were observed after regeneration. Finally, the used air cathodes could be utilized for CO₂ capture, thereby reducing the impact of CO₂ emission. This study aims to show that Li-O₂ batteries can not only serve as a device of high energy density but also as a solution to a greener future.