Anchoring NiO Nanosheet on the Surface of CNT to Enhance the Performance of a Li-O 2 Battery.

Li 2 O 2 , as the cathodic discharge product of aprotic Li-O 2 batteries, is difficult to electrochemically decompose. Transition-metal oxides (TMOs) have been proven to play a critical role in promoting the formation and decomposition of Li 2 O 2 . Herein, a NiO/CNT catalyst was prepared by anchoring a NiO nanosheet on the surface of CNT. When using the NiO/CNT as a cathode catalyst, the Li-O 2 battery had a lower overpotential of 1.2 V and could operate 81 cycles with a limited specific capacity of 1000 mA h g -1 at a current density of 100 mA g -1 . In comparison, with CNT as a cathodic catalyst, the battery could achieve an overpotential of 1.64 V and a cycling stability of 66 cycles. The introduction of NiO effectively accelerated the generation and decomposition rate of Li 2 O 2 , further improving the battery performance. SEM and XRD characterizations confirmed that a Li 2 O 2 film formed during the discharge process and could be fully electrochemical decomposed in the charge process. The internal network and nanoporous structure of the NiO/CNT catalyst could provide more oxygen diffusion channels and accelerate the decomposition rate of Li 2 O 2 . These merits led to the Li-O 2 battery's better performance.