摘要
有机电极材料因具有结构多样性和可持续性,在水系钾离子电池研究领域展示出广阔的前景,但它们大多数存在导电性差、易溶于电解液的问题,导致电极活性物质利用率低、循环稳定性差.本文通过含氮苯环的共轭延申、引入氰基活性中心,获得了3CN-HATN.与经#吩嗪负极相比,3CN-HATN的最低未占据分子轨道能级更低,更容易被还原,且其能带隙较窄,改善了导电性,其共轭结构可有效抑制循环过程中3CN-HATN的溶解.3CN-HATN负极在80 C(1 C=350 mA g^(-1))下比容量高达233.8 mA h g^(-1),将其与Ni(OH)_(2)正极匹配,构建的水系钾离子全电池具备优异的循环稳定性和快充性能,30 C下循环10,000圈后容量保持率达81.5%.
Organic electrode materials hold great promise for advancing the development of aqueous potassium-ion batteries(AKIBs)due to their structural diversity and sustainability.However,they still encounter challenges such as low electroactive mass contribution and undesirable cycling performance resulting from intrinsic poor electronic conductivity and severe solubility issues.Herein,tricyano-substituted hexaazatrinnphthalene(3CN-HATN)was designed by enlarging the conjugated N-heteroaromatic structure and introducing cyano(C≡N)moieties as additional redox centers.Compared with the typical phenazine anode,the decrease in the lowest unoccupied molecular orbital energy level endows 3CN-HATN with a preferable reduction reaction.The narrower band gap ensures higher utilization of 3CN-HATN,while the elongation ofπ-conjugated structure effectively inhibits the dissolution in aqueous electrolytes.As a result,the 3CN-HATN anode achieves a remarkable capacity of 233.8 mA h g^(-1) at an ultrahigh rate of 80 C(1 C=350 mA g^(-1)),retaining an impressive 87.5%of the capacity at 2 C.When coupled with commercial Ni(OH)_(2) cathode,the as-assembled full cells exhibit outstanding cycling stability,maintaining a capacity retention of 81.5%after 10,000 cycles at 30 C.This work underscores the significance of molecular engineering in the development of redox-active organic materials for constructing high-performance AKIBs.
作者
郑易帆
于丹丹
王健晨
杨杰
罗稳
戈天奇
秦来顺
黄岳翔
陈达
Yifan Zheng;Dandan Yu;Jianchen Wang;Jie Yang;Wen Luo;Tianqi Ge;Laishun Qin;Yuexiang Huang;Da Chen(College of Materials and Chemistry,China Jiliang University,Hangzhou,310018,China;Hydrogen Energy Research Center PetroChina Petrochemical Research Institute,Beijing,102200,China)
基金
supported by the National Natural Science Foundation of China(52002081 and 51972294)
the National College Students Innovation and Entrepreneurship Training Program(202310356033)
the Science and Technology Innovation Activity Program for College Students in Zhejiang Province(New Seedling Talent Program)Project(2024R409055)。
