泡沫镍@石墨烯水凝胶@镍钴氢氧化物的制备及其超级电容性能

Preparation of foam nickel@graphene hydrogel@nickel cobalt hydroxides and the supercapacitive performance

采用水热法将石墨烯生长到泡沫镍上,获得泡沫镍@石墨烯水凝胶基底材料(NF@GH),再以十六烷基三甲基溴化铵(CTAB)为导向剂,在120℃下水热反应后得到NF@GH@NiCoLDH。并研究了石墨烯水凝胶对NF@GH@NiCoLDH复合材料电化学性能的影响。1 mA cm^(-2)电流密度下NF@GH@NiCoLDH的比容量可达3658 mF cm^(-2),15 mA cm^(-2)时的比容量保持率为67.5%,高于NF@NiCoLDH(58%);10000次循环后的容量保持率为62%(15 mA cm^(-2)),具有较好的循环稳定性和倍率性能。以NF@GH@NiCoLDH为正极材料组装的不对称超级电容器比容量为909 mF cm^(-2)(1 mA cm^(-2)),器件的最高能量密度为0.25 mWh cm^(-2)(功率密度为0.7 mW cm^(-2))。

Graphene was grown on foam nickel to obtain Ni foam@graphene hydrogel(NF@GH)by hydrothermal method,and then using cetyltrimethylammonium bromide(CTAB)as guiding agent,NF@GH@NiCoLDH was obtained by hydrothermal treatment at 120℃.The effect of graphene hydrogel on the electrochemical properties of the NF@GH@NiCoLDH composite was also investigated.The specific capacitance of NF@GH@NiCoLDH could reach 3658 mF cm^(-2) at 1 mA cm^(-2),and the retention rate of the specific capacitance is 67.5%at 15 mA cm^(-2),which is higher than that of NF@NiCoLDH(58%).And 62%of the capacitance is retained after 10000 cycles at 15 mA cm^(-2),showing good cycle stability and rate performance.The asymmetric supercapacitor device was assembled with NF@GH@NiCoLDH as the positive electrode,which has a specific capacitance of 909 mF cm^(-2)at 1 mA cm^(-2),and the maximum energy density of the device is 0.25 mWh cm^(-2),when the power density is 0.7 mW cm^(-2).