Co金属有机骨架模板制备NiCo水滑石/泡沫镍复合材料及电容性能

Preparation by Co metal-organic framework template and capacitive properties of NiCo-layered double hydroxide/nickel foam composites

通过两步法先在泡沫镍(nickel foam,NF)上原位生长Co金属有机骨架(Co metal-organic framework,Co-MOF)纳米片阵列,再浸入不同浓度Ni^(2+)离子溶液刻蚀Co-MOF纳米片,在NF表面得到NiCo水滑石(NiCo layered double hydroxide,NiCo-LDH)。NiCo-LDH/NF继承了Co-MOF纳米片结构形成一级纳米片阵列,并在一级纳米片表面形成次级纳米片褶皱。在2 mmol Ni(NO_(3))2·6H_(2)O溶液中刻蚀得到的NiCo-LDH/NF表现出高容量、高倍率性能,在电流密度为5 mA·cm^(-2)时比电容为7 764.5 mF·cm^(-2),电流密度为20 mA·cm^(-2)时比电容为6 098.2 mF·cm^(-2),容量保持率为78.5%,在20 A·g^(-1)电流密度下经过5 000次长循环后,容量保持率为85.9%。与活性炭组装的混合电容器达到38.9 Wh·kg^(-1)的最大能量密度和8 000.0 W·kg^(-1)的最大功率密度。

Using a two‑step method,a Co metal‑organic framework(Co‑MOF)nanosheet array was grown in situ on nickel foam(NF),and then Co‑MOF nanosheets were etched with different concentrations of Ni^(2+)ion solution to obtain NiCo layered double hydroxide(NiCo‑LDH).NiCo‑LDH/NF inherits the Co‑MOF nano‑sheet structure to form a primary nano‑sheet array and a secondary nano‑sheet fold on the surface of the primary nano‑sheet.NiCo‑LDH/NF obtained by etching in 2 mmol Ni(NO_(3))2·6H_(2)O solution showed a small number of thin and folded secondary nano‑sheets grown on the primary nano‑sheet array,exhibited a high capacitance and high rate performance,had a specific capacitance of 7764.5 and 6098.2 mF·cm^(-2) at a current density of 5 and 20 mA·cm^(-2),and capacitance retention rate of 78.5%.After 5000 cycles at a current density of 20 A·g^(-1),the capacitance retention rate was 85.9%.The hybrid capacitor assembled by NiCo‑LDH/NF and active carbon achieved an maximum energy density of 38.9 Wh·kg^(-1) and a maximum power density of 8000.0 W·kg^(-1).