Controlled Growth of Li₂O₂ by Cocatalysis of Mobile Pd and Co₃O₄ Nanowire Arrays for High-Performance Li–O₂ Batteries

For Li–O 2 batteries, a challenge still remains to achieve high discharge capacity and easy decomposition of the discharge product (Li 2 O 2 ) simultaneously. In this work, conformal growth of thin-layered Li 2 O 2 on Co 3 O 4 nanowire arrays (Co 3 O 4 NAs) during discharge is realized through the cocatalytic effect of solid/immobile Co 3 O 4 NAs and mobile Pd nanocrystals (Pd NCs), rendering easy decomposition of Li 2 O 2 during recharge. Meanwhile, high discharge capacity is also ensured with unique array-type design of the catalytic cathode despite the surface growth mode of Li 2 O 2 . The Li–O 2 cells can deliver a high discharge capacity of 5337 mAh g –1 and keep a stable cycling of 258 cycles at a limited capacity of 500 mAh g –1 . The achievement of excellent electrochemical performance is attributed to the highly efficient cocatalytic ability of Co 3 O 4 NAs and Pd NCs as well as the desirable array-type architecture of the catalytic electrode free of carbon and binder. The cocatalytic mechanism of Co 3 O 4 NAs and Pd NCs is clarified by systematic electrochemical tests, microstructural analyses, and ζ-potential measurements.