Graphene films suffer from poor electrochemical performance due to the undesirable ion diffusion inside its deep area and only electrical double layer absorption mechanism. Here, we proposed a freeze casting method for fabricating the N-rich holey reduced graphene oxide films (Freeze-dried N-HRGO) bearing cross-coupled porous ion diffusion networks. The H₂O₂ etching and modified vacuum filtration process generate abundant pore structures inside films, which act as ion diffusion path for promoting electrochemical performance. In addition, the N sites serve as pseudocapacitance contributor to react with electrolyte ions, which greatly enhance the specific capacitance. As a result, the freeze-dried N-HRGO films show a high specific capacitance of 528 F g⁻¹ at a current density of 1 A g⁻¹. When assembled into symmetrical supercapacitor, it delivers a high energy density of 14.0 Wh kg⁻¹ and excellent cycle life (89.3% capacity retention after 5000 cycles at 2 A g⁻¹).

石墨烯薄膜由于其深部区域内不希望的离子扩散和仅有双电层吸收机制而遭受较差的电化学性能。在这里，我们提出了一种冷冻浇铸方法，用于制造具有交叉耦合多孔离子扩散网络的富氮多孔还原氧化石墨烯薄膜（冷冻干燥 N-HRGO）。H ₂ O ₂蚀刻和改进的真空过滤工艺在薄膜内部产生丰富的孔隙结构，作为离子扩散路径，促进电化学性能。此外，N 位点作为赝电容贡献者与电解质离子反应，大大提高了比电容。结果，冷冻干燥的 N-HRGO 薄膜显示出 528 F g ^-1的高比电容在1 A g ^-1的电流密度下。当组装成对称超级电容器时，它提供了 14.0 Wh kg ^-1的高能量密度和出色的循环寿命（在 2 A g ^{-1 下}5000 次循环后容量保持率为 89.3% ）。