锌阳极氮掺杂多孔碳表面功能层设计及可逆性研究

Design and Reversibility Study of Nitrogen-doped Porous Carbon Surface Functional Layer for Zinc Anodes

锌阳极因枝晶生长、析氢、形变和钝化等挑战,成为限制锌空气电池充放电循环性能的关键因素。本工作以聚季铵盐为碳源和氮源,通过硬模板法制备出具有丰富介孔结构的碳材料,并将其作为锌阳极的表面功能层(N-MC@Zn)。其中,N-MC@Zn的比表面积高达590.06 m^(2)·g^(-1),平均孔径为22 nm。研究表明,锌阳极表面构建氮掺杂的多孔碳功能层,在一定程度上有效缓解了上述寄生反应带来的负面影响。特别是多孔碳涂层丰富的孔隙为锌沉积/剥离提供了缓冲区,极大提高了锌离子的沉积动力学,稳定了其沉积/剥离过程,缓解了锌阳极的析氢腐蚀;此外,多孔碳涂层内的各向异性避免了尖端效应,抑制了枝晶生长。基于上述优势,N-MC@Zn表现出优异的充放电稳定性(140 h, 700次循环)、倍率充放电特性(0.5C~10C)以及放电容量。以上结果表明,多孔碳材料可作为高性能锌阳极功能层材料,为锌阳极涂层设计领域提供了新的视角。

Zinc anode has become a key factor limiting the cycling performance of zinc-air batteries due to challenges such as dendrite growth,hydrogen evolution,deformation,and passivation.In this study,carbon materials with abundant mesoporous structures were prepared using quaternary ammonium salts as carbon and nitrogen sources through a hard template method,and they were used as a surface functional layer for the zinc anode(N-MC@Zn).The N-MC@Zn material had a high specific surface area of 590.06 m^(2)·g^(-1) and an average pore size of 22 nm.The research showed that constructing a nitrogen-doped porous carbon functional layer on the surface of the zinc anode effectively mitigated the negative effects caused by the aforementioned challenges.In particular,the abundant pores in the porous carbon coating provided a buffer zone for zinc deposition/stripping,greatly accelerating the deposition kinetics and stabilizing the deposition/stripping process of zinc ions,thus alleviating hydrogen evolution corrosion of the zinc anode.Furthermore,the anisotropy within the porous carbon coating prevented the growth of dendrites by avoiding the tip effect.Based on these advantages,N-MC@Zn exhibited excellent discharge and charge stability(140 h,700 cycles),rate capability(from 0.5C to 10C),and discharge capacity.These results demonstrate that porous carbon materials can serve as high-performance functional layer materials for zinc anodes and provide a new perspective for the design of zinc anode coatings.