Department of Applied Chemistry, College of Chemistry and Chemical Engineering , Chongqing University , Chongqing 401331 , P. R. China.
State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering , Peking University , Beijing 100871 , P. R. China.
ACS Appl Mater Interfaces. 2018 Sep 19;10(37):31340-31354. doi: 10.1021/acsami.8b09836. Epub 2018 Sep 5.
Ni-doped Co(HPO)(OH) with different morphologies was directly grown on Ni foam hydro(solvo)thermally under different synthetic conditions. The optimum condition is solvothermal reaction for 6 h in an ethanol/water (EW) mixed solution, the molar ratio of NaHPO/Co(NO) being 0.5:0.1, and the obtained S0.5-6 h-EW shows three-dimensional (3D) porous nanowire bundles. Whereas in the water-only solution, microrods are obtained, suggesting that the nanowires in bundles are aggregated together via the lateral (400) direction. Long reaction time and low molar ratio of reactants are all beneficial for the lateral growth of the nanowires, and the possible formation mechanism is proposed. All the obtained Ni-doped Co(HPO)(OH)/Ni foam samples are directly used as supercapacitor electrodes, and S0.5-6 h-EW shows the best electrochemical performance with a specific capacity of 159 mAh g at 0.5 A g, which is close to the theoretical value of 212 mAh g for Co(HPO)(OH), and it is the largest reported value so far. The excellent capacitive behavior of S0.5-6 h-EW is ascribed to the 3D porous nanowire bundles directly grown on a Ni foam collector without an additive and a binder, as well as to the doping of Ni into the cobalt phosphite. The S0.5-6 h-EW//activated carbon asymmetrical supercapacitor shows a maximum energy density of 58.7 Wh kg at a power density of 532 W kg and good cycling stability with the capacity retention of 90.5% after 10 000 charging-discharging cycles at 5.5 A g.
在不同的合成条件下，通过水热（溶剂热）法直接在泡沫镍上生长出具有不同形貌的 Ni 掺杂 Co(HPO)(OH)。最佳条件是在乙醇/水（EW）混合溶液中进行溶剂热反应 6 小时，NaHPO/Co(NO)的摩尔比为 0.5:0.1，得到的 S0.5-6 h-EW 呈三维（3D）多孔纳米线束。而在只有水的溶液中，则得到了微棒，表明束中的纳米线通过（400）方向的横向聚集在一起。长的反应时间和反应物的低摩尔比都有利于纳米线的横向生长，并提出了可能的形成机制。所有得到的 Ni 掺杂 Co(HPO)(OH)/泡沫镍样品都直接用作超级电容器电极，S0.5-6 h-EW 表现出最佳的电化学性能，在 0.5 A g 下的比容量为 159 mAh g，接近 Co(HPO)(OH)的理论值 212 mAh g，这是迄今为止报道的最大值。S0.5-6 h-EW 的优异电容行为归因于直接生长在 Ni 泡沫集电器上的 3D 多孔纳米线束，无需添加物和粘合剂，以及 Ni 掺杂到钴磷酸盐中。S0.5-6 h-EW//活性炭非对称超级电容器在 532 W kg 的功率密度下表现出最大的能量密度 58.7 Wh kg，并且在 5.5 A g 下经过 10000 次充放电循环后，容量保持率为 90.5%，具有良好的循环稳定性。
