Lignin-derived self-assembled 2D N-doped carbon nanosheets as effective oxygen-redox electrocatalysts for rechargeable zinc-air batteries.

Two-dimensional (2D) carbon nanomaterials are widely used in electrocatalytic reactions due to their enhanced electron mobility and excellent structural stability. Nevertheless, the complexity of its synthesis process limits its large-scale application. In this study, layered porous 2D lignin-derived carbon nanosheets were successfully synthesized using various salts as templates combined with an antisolvent technique. When employed as cathode catalysts for zinc-air batteries (ZABs), the catalysts demonstrated remarkable oxygen reduction reaction (ORR) activity. The catalyst has a half-wave potential (E1/2) of approximately 0.883 V, which is significantly higher than that of Pt/C. And the catalyst exhibits excellent methanol tolerance and long-term operational stability. Moreover, the investigation revealed that the rechargeable ZABs assembled with the electrocatalyst achieved a peak power density of up to 151 mW·cm-2 and specific capacities of 821.5 mAh·g-1. This study develops a novel approach to synthesize 2D carbon nanosheets integrating cost-effectiveness, environmentally benign and facile processing, and high catalytic activity.