High‐Performance Li–O 2 Batteries with Controlled Li 2 O 2 Growth in Graphene/Au‐Nanoparticles/Au‐Nanosheets Sandwich

The working of nonaqueous Li–O 2 batteries relies on the reversible formation/decomposition of Li 2 O 2 which is electrically insulating and reactive with carbon and electrolyte. Realizing controlled growth of Li 2 O 2 is a prerequisite for high performance of Li–O 2 batteries. In this work, a sandwich‐structured catalytic cathode is designed: graphene/Au‐nanoparticles/Au‐nanosheets (G/Au‐NP/Au‐NS) that enables controlled growth of Li 2 O 2 spatially and structurally. It is found that thin‐layer Li 2 O 2 (below 10 nm) can grow conformally on the surface of Au NPs confined in between graphene and Au NSs. This unique crystalline behavior of Li 2 O 2 effectively relieves or defers the electrode deactivation with Li 2 O 2 accumulation and largely reduces the contact of Li 2 O 2 with graphene and electrolyte. As a result, Li–O 2 batteries with the G/Au‐NP/Au‐NS cathode exhibit superior electrochemical performance. A stable cycling of battery can last 300 times at 400 mA g −1 when the capacity is limited at 500 mAh g −1 . This work provides a practical design of catalytic cathodes capable of controlling Li 2 O 2 growth.