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

Abstract

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.