Nitrogen-rich hierarchical porous carbon nanoscrolls with atomically dispersed Co sites for the enhanced oxygen reduction reaction and lithium-ion batteries

The inherent properties, poor exposed active sites and the cumbersome manufacturing process have severely hindered metal-nitrogen-carbon structures in their applications in electric vehicles and stationary energy storage systems. Herein, we report a novel pyrolysis-induced gas diffusion strategy to synthesize nitrogen-rich hierarchical porous carbon nanoscrolls with highly dispersed single-atom Co sites (Co-N-C) as electrode materials for the electrocatalytic oxygen reduction and lithium-ion batteries (LIBs). In this method, Co doped g-C3N4 (Co-CN) is not only used to anchor Co single-atoms to increase the intrinsic active sites, but also served as a sacrificial template to adjust the N content and increase the electrochemically active surface area of the carbon material. Furthermore, self-curling and in situ produced NH3 from Co-CN diffusion effects tune the structural characteristics of the mesoporous carbon nanoscrolls to fully expose the active center and facilitate rapid ion transport. As a result, these carbon nanoscrolls display an enhanced oxygen reduction reaction (ORR) with a half-wave potential of 0.87 V vs. RHE, better than that of the state-of-the-art Pt/C catalyst, and a superior electrochemical performance as an anode material for LIBs, showing a specific capacity of 589.1 mA h g(-1) at 2.0 A g(-1) even after 900 cycles. Such a finding provides a facile pyrolysis-induced gas diffusion strategy for synthesizing high performance electrode materials.