The stability of various polymer binders was systematically investigated in the oxygen-rich environment required for the operation of Li–O2 batteries. Due to the coverage on air electrode surface by the discharge products and decomposition products of the electrolyte during the discharge process of Li–O2 batteries, the binder in the air electrode is hard to be detected making the evaluation of its stability problematic. Therefore, stability of the binder polymers against the reduced oxygen species generated during the discharge process was investigated by ball milling the polymers with KO2 and Li2O2, respectively. Most of the studied polymers are unstable under these conditions and their decomposition mechanisms are proposed according to the analyzed products. Polyethylene was found to exhibit excellent stability when exposed to superoxide and peroxide species and is suggested as a robust binder for air electrodes. In addition, the binding strength of the polymer significantly affects the discharge performance of Li–O2 batteries.