We controllable designed and synthesized four kinds of three-dimensional (3D) hierarchical nanostructured Co₃O₄ thin films directly deposited on the nickel foam surface by a facile chemical bath deposition method. The morphologies of the Co₃O₄ films were regulated by using different anions (SO₄²⁻, NO₃⁻, Cl⁻, and CH₃COO⁻) originated from the precursors. The effect of different anions on the surface morphologies and pseudocapacitance behaviors of Co₃O₄ films was investigated by multiple electrochemical methods, including cyclic voltammetry (CV), galvanostatic charge-discharge cycles (GCD) and electrochemical impedance spectroscopies (EIS). The results indicated that the anions in the precursor salts greatly affected the morphology and porosity of the Co₃O₄ thin film, and consequently exhibited the different electrochemical performances in 2.0 M KOH electrolyte. The Co₃O₄ thin film prepared from cobalt acetate shown excellent electrochemical performance among the four different Co₃O₄ thin films electrodes, such as a high specific capacitance (743.8 F·g⁻¹) and nice cycling stability (95.8% retention after 1000 charge-discharges at a high current density of 5 A·g⁻¹). Furthermore, this work also provides a facile large-scale fabrication method to prepare secondary nanostructure on pseudocapacitance materials, such as graphene, transition metal oxides, carbon fibers, for enhancing the electrochemical performance of supercapacitor at low operation temperature.

我们可控设计并合成了四种三维（3D）分级纳米结构Co ₃ O ₄薄膜，通过简便的化学浴沉积方法直接沉积在镍泡沫表面。Co ₃ O ₄薄膜的形态通过使用源自前体的不同阴离子（SO ₄ ^2-、NO ₃ ^-、Cl ^-和CH ₃ COO ^-）来调节。不同阴离子对Co ₃ O ₄表面形貌和赝电容行为的影响通过多种电化学方法对薄膜进行了研究，包括循环伏安法 (CV)、恒电流充放电循环 (GCD) 和电化学阻抗谱 (EIS)。结果表明，前体盐中的阴离子极大地影响了Co ₃ O ₄薄膜的形貌和孔隙率，从而在2.0 M KOH电解液中表现出不同的电化学性能。由醋酸钴制备的 Co ₃ O ₄薄膜在四种不同的 Co ₃ O ₄薄膜电极中表现出优异的电化学性能，如高比电容（743.8 F·g ^-1) 和良好的循环稳定性（在 5 A·g ^-1的高电流密度下充放电 1000 次后保持率达 95.8% ）。此外，这项工作还提供了一种简便的大规模制备方法，可以在赝电容材料（如石墨烯、过渡金属氧化物、碳纤维）上制备二级纳米结构，以提高超级电容器在低温下的电化学性能。