The design of supercapacitor materials with both high areal capacity (C) and high mass loading is vitally important for enhancing energy density (E). Herein, we prepared a NiCoOH/NiCoOOH composite film consisting of NiCoOH/NiCoOOH nanosheets on an expanded graphite paper (EGP) by using a facial anodization method. The as-prepared NiCoOH/NiCoOOH film exhibits ultra-high C of 11 mA·h·cm⁻² at a mass loading of 165 mg·cm⁻², high rate capability of 71% and excellent cycling stability of 95% after 12 000 cycles. The outstanding performance is ascribed to the low-crystalline feature of the NiCoOH/NiCoOOH nanosheets, and the synergistic effect of the NiCoOH and NiCoOOH phases and high conductive porous EGP. An aqueous asymmetric supercapacitor, assembled with the NiCoOH/NiCoOOH on EGP and Fe₂O₃ on EGP as positive- and negative-electrode, respectively, shows a highest E of 3.8 mW·h·cm⁻² at a power density (P) of 4 mW·cm⁻² and a maximum P of 107 mW·cm⁻² at an E of 2.7 mW·h·cm⁻².

设计具有高面容量 ( C ) 和高质量负载的超级电容器材料对于提高能量密度 ( E )至关重要。在此，我们通过使用面阳极氧化法在膨胀石墨纸（EGP）上制备了由 NiCo OH/NiCoOOH 纳米片组成的 NiCo OH/NiCoOOH 复合膜。所制备的NiCo OH/NiCoOOH 薄膜在 165 mg·cm ^-2的质量负载下表现出11 mA·h·cm ^-2的超高C、71% 的高倍率性能和 12 小时后 95% 的优异循环稳定性000 次循环。出色的性能归因于NiCo OH/NiCoOOH 纳米片的低结晶特性，以及 NiCo 的协同效应OH 和 NiCoOOH 相和高导电多孔 EGP。水系不对称超级电容器，分别在 EGP 上组装NiCo OH/NiCoOOH 和在 EGP 上组装 Fe ₂ O ₃作为正极和负极，在功率密度下表现出3.8 mW·h·cm ^{−2的最高}E ( P ) 为 4 mW·cm ^-2并且在E为 2.7 mW·h·cm ^-2时最大P为 107 mW· cm ^-2。