The controllable construction of nanochannel in two-dimensional lamellar film for efficient oxygen reduction reaction and lithium-oxygen batteries.

A free-standing flexible Co-MOF/MXene hybrid film was prepared by inserting 2D Co-MOF nanosheets between MXene layers based on layer upon layer self-assembly strategy. Li-O 2 batteries based on Co-MOF/MXene film as cathode have ultra-high capacity, excellent cycle stability and excellent rate performance. [Display omitted] • A free-standing flexible hybird film was prepared as cathode for Li-O 2 batteries. • The Co-MOF/MXene hybrid film has high ORR catalytic activity. • The interlayer spacing of MXene can be regulated by 2D Co-MOF. • The performance of Li-O 2 batteries can be controlled. Lithium-oxygen (Li-O 2) batteries are considered as a new revolutionary energy storage technology due to their ultra-high theoretical energy density, but many problems of cathode restrict their further development. Here, we prepared a free-standing flexible Co-MOF/MXene hybird film for efficient Oxygen reduction reaction (ORR) and as cathode for Li-O 2 batteries by inserting 2D Co-MOF nanosheets between MXene layers based on electrostatic self-assembly strategy. The Co-MOF/MXene hybrid film with two-dimensional lamellar structure had high ORR catalytic activity, can provide faster Li+ or O 2 expansion channels, promotes the deposition and decomposition of Li 2 O 2 , and it also breaks through the traditional concept of slurry method to prepare cathode of Li-O 2 batteries. Li-O 2 batteries based on Co-MOF/MXene hybird film as cathode had ultra-high capacity (34763 mAh/g at current density of 1000 mA/g), excellent cycle stability (278 cycles, limited capacity of 1000 mAh/g at current density of 1000 mA/g), and outstanding rate performance. Besides, the capacity and cycle performance of Li-O 2 batteries can be controlled by adjusting the loading of 2D Co-MOF and the thickness of Co-MOF/MXene hybrid film. The promising results provide insights the construction of air cathode structure for metal-air batteries, the design of efficient catalyst, and greatly expanded the scope of future research. [ABSTRACT FROM AUTHOR]