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3C...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%.展开更多
Potassium ion-based dual-graphite batteries(KDGBs)emerge as promising devices for large-scale applications due to their high voltage,low cost,environmental friendliness.However,conventional KPF6/carbonate-based electr...Potassium ion-based dual-graphite batteries(KDGBs)emerge as promising devices for large-scale applications due to their high voltage,low cost,environmental friendliness.However,conventional KPF6/carbonate-based electrolytes suffer from severe oxidation decomposition,low concentration,flammability,which limit the capacity and cyclability of KDGBs.Herein,a nonflammable potassium bis(fluorosulfonyl)imide/triethyl phosphate(KFSI/TEP)electrolyte was designed for KDGBs.When the salt-to-solvent molar ratio increases to 1:1.3,graphite cathode operated at the cut-off potential of 5.2 V exhibits much enhanced capacity,excellent rate capability(26.4 mAh∙g^(−1) at 1.0 A∙g^(−1)),superior cyclability with 98%capacity retention after 350 cycles.Inorganic compounds-rich electrode/electrolyte interphase layers derived from the preferential decomposition of FSI−anions ensure good compatibility of the 1:1.3 KFSI/TEP electrolyte with K metal and graphite anodes.Based on this electrolyte,asassembled KDGBs show high operation voltage of 4.3 V and good cycling performance.This work provides feasibility for developing long-life and safe-operation DGBs.展开更多
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)。
文摘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%.
基金the National Natural Science Foundation of China(Nos.52002081,51972294,and 51872271).
文摘Potassium ion-based dual-graphite batteries(KDGBs)emerge as promising devices for large-scale applications due to their high voltage,low cost,environmental friendliness.However,conventional KPF6/carbonate-based electrolytes suffer from severe oxidation decomposition,low concentration,flammability,which limit the capacity and cyclability of KDGBs.Herein,a nonflammable potassium bis(fluorosulfonyl)imide/triethyl phosphate(KFSI/TEP)electrolyte was designed for KDGBs.When the salt-to-solvent molar ratio increases to 1:1.3,graphite cathode operated at the cut-off potential of 5.2 V exhibits much enhanced capacity,excellent rate capability(26.4 mAh∙g^(−1) at 1.0 A∙g^(−1)),superior cyclability with 98%capacity retention after 350 cycles.Inorganic compounds-rich electrode/electrolyte interphase layers derived from the preferential decomposition of FSI−anions ensure good compatibility of the 1:1.3 KFSI/TEP electrolyte with K metal and graphite anodes.Based on this electrolyte,asassembled KDGBs show high operation voltage of 4.3 V and good cycling performance.This work provides feasibility for developing long-life and safe-operation DGBs.
