Cobalt-copper layered double hydroxide nanosheets as high performance bifunctional catalysts for rechargeable lithium-air batteries

Abstract Designing novel cost-effective catalysts is one of the greatest challenges in the development of high-performance rechargeable Li-air battery. Here, we report the synthesis of novel cobalt-copper layered double hydroxide (LDH) nanosheets via a simple co-precipitation method under Ar gas. The resulting Co-Cu LDH nanosheets, possessing an average thickness of 4.3 nm and a high surface area of 163 m 2  g −1 , have been applied as bifunctional catalysts for Li-air battery. In the simulated air environment, Li-air batteries with Co-Cu LDH nanosheets demonstrate higher discharge capacity of 4870 mAh g −1 at 200 mA g −1 , lower charge overpotential and better cycling stability with controlling capacity of 1000 mAh g −1 , which is much better than that with CuCo 2 O 4 electrode. The enhanced electrochemical performance is ascribed to the large interface between electrolytes and catalysts resulting from high surface area of Co-Cu LDH, providing plenty of actives sites to promote the formation/decomposition of Li 2 O 2 . The unique ultrathin nanosheet structure of Co-Cu LDH can also facilitate the mass transportation of O 2 and ions in Li-air battery.