N-doped carbon nanosheets derived from lignin as a novel bifunctional electrocatalyst for rechargeable zinc-air battery

New energy utilization devices have attracted great research interest as a sustainable route for clean energy production. However, the disadvantage of this process is the need to use high-cost precious metal catalysts. Hereby, N-doped carbon nanosheets (LNZ@GC) was prepared by ball milling-carbonization two step strategy using alkali lignin as carbon source and the gas-phase exfoliation with NH₄Cl and ZnCl₂ as pore-forming agents. We investigative the properties of LNZ@GC series and find that LNZ@GC exhibit the most excellent ORR performances with a half-wave potential up to 0.851 V, outstanding stability and methanol tolerance, which are all superior commercial Pt/C. Furthermore, the rechargeable zinc-air battery assembled by LNZ-800@GC shows excellent performance with a high power density of 841.8 Wh kg⁻¹, a large specific capacity of 750.3 mA h g⁻¹. This work not only provides a general strategy for the preparation of porous N-doped catalysts, but also provides technical support for the design and development of inexpensive catalysts using lignin as a carbon source.