• Lamellar-structured graphene aerogels with vertically aligned and closely stacked high-quality graphene lamellae are fabricated.

• The superior thermally conductive capacity of the aerogel endows epoxy with a high through-plane thermal conductivity of 20.0 W m⁻¹ K⁻¹ at 2.30 vol% of graphene content.

• The nacre-like structure endows the epoxy composite with enhanced fracture toughness.

Although thermally conductive graphene sheets are efficient in enhancing in-plane thermal conductivities of polymers, the resulting nanocomposites usually exhibit low through-plane thermal conductivities, limiting their application as thermal interface materials. Herein, lamellar-structured polyamic acid salt/graphene oxide (PAAS/GO) hybrid aerogels are constructed by bidirectional freezing of PAAS/GO suspension followed by lyophilization. Subsequently, PAAS monomers are polymerized to polyimide (PI), while GO is converted to thermally reduced graphene oxide (RGO) during thermal annealing at 300 °C. Final graphitization at 2800 °C converts PI to graphitized carbon with the inductive effect of RGO, and simultaneously, RGO is thermally reduced and healed to high-quality graphene. Consequently, lamellar-structured graphene aerogels with superior through-plane thermal conduction capacity are fabricated for the first time, and its superior through-plane thermal conduction capacity results from its vertically aligned and closely stacked high-quality graphene lamellae. After vacuum-assisted impregnation with epoxy, the resultant epoxy composite with 2.30 vol% of graphene exhibits an outstanding through-plane thermal conductivity of as high as 20.0 W m⁻¹ K⁻¹, 100 times of that of epoxy, with a record-high specific thermal conductivity enhancement of 4310%. Furthermore, the lamellar-structured graphene aerogel endows epoxy with a high fracture toughness, ~ 1.71 times of that of epoxy.

• 制备了具有垂直排列和紧密堆叠的高质量石墨烯薄片的层状结构石墨烯气凝胶。

• 气凝胶优异的导热能力使环氧树脂在石墨烯含量为 2.30 vol% 时具有 20.0 W m ^-1 K ^{-1的高贯穿平面导热率。}

• 珍珠层状结构赋予环氧树脂复合材料增强的断裂韧性。

尽管导热石墨烯片在提高聚合物的面内热导率方面是有效的，但由此产生的纳米复合材料通常表现出低的面内热导率，限制了它们作为热界面材料的应用。在此，层状结构的聚酰胺酸盐/氧化石墨烯 (PAAS/GO) 混合气凝胶是通过 PAAS/GO 悬浮液的双向冷冻然后冻干来构建的。随后，PAAS 单体聚合成聚酰亚胺 (PI)，而 GO 在 300°C 的热退火过程中转化为热还原氧化石墨烯 (RGO)。在 2800 °C 的最终石墨化将 PI 转化为具有 RGO 感应效应的石墨化碳，同时，RGO 被热还原并修复为高质量的石墨烯。最后，首次制备出具有优异平面热传导能力的层状结构石墨烯气凝胶，其优异的平面热传导能力源于其垂直排列和紧密堆叠的高质量石墨烯薄片。在用环氧树脂进行真空辅助浸渍后，所得的含有 2.30 vol% 石墨烯的环氧树脂复合材料表现出高达 20.0 W m 的出色的平面热导率^-1 K ^-1，是环氧树脂的100倍，比热导率提高了4310%，创历史新高。此外，层状结构的石墨烯气凝胶赋予环氧树脂高断裂韧性，约为环氧树脂的 1.71 倍。