Xu Xuan, Li Zhenhu, Li Haoxiang, Li Yongsu, Zeng Yu, Liu Shuangyi
Research Center of Electrochemical Energy Storage Technologies, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, People's Republic of China.
Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, People's Republic of China.
Nanotechnology. 2024 Aug 22;35(45). doi: 10.1088/1361-6528/ad6774.
Scalable production of reduced graphene oxide (rGO) films with high mechanical-electrical properties is desirable as these films are candidates for wearable electronics devices and energy storage applications. Removing structural incompleteness such as wrinkles or voids in the graphene films, which are generated from the assembly process, would greatly optimize their mechanical properties. However, the densely stacked graphene sheets in the films degrade their ionic kinetics and thus limit their development. Here, a horizontal-longitudinal-structure modulating strategy is demonstrated to produce enhanced mechanical, conductive, and capacitive graphene films. Typically, two-dimensional large graphene sheets (LGS) induce regular stacking of graphene oxide (GO) during the assembly process to reduce wrinkles, while one-dimensional single-walled carbon nanotubes (SWCNT) bridge with graphene sheets to strengthen the multidirectional intercalation and reduce GO layer restacking. The simultaneous incorporation of LGS and SWCNT synergistically creates a fine microstructure by improving the alignment of graphene sheets, increasing continuous conductive pathways to facilitate electron transport, and enlarging interlayer spacing to promote electrolyte ion diffusion. As a result, the obtained graphene films are flat and exhibit signally reinforced mechanical properties, electrical conductivity (38727 S m), as well as specific capacitance (232 F g) as supercapacitor electrodes compared to those of original rGO films. Moreover, owing to the comprehensive improved properties, a flexible gel supercapacitor assembled by the graphene film-based electrodes shows high energy density, good flexibility, and excellent cycling stability (93.8% capacitance retention after 10 000 cycles). This work provides a general strategy to manufacture robust graphene structural materials for energy storage applications in flexible and wearable electronics.
可扩展生产具有高机械 - 电学性能的还原氧化石墨烯（rGO）薄膜是很有必要的，因为这些薄膜是可穿戴电子设备和储能应用的候选材料。消除石墨烯薄膜在组装过程中产生的诸如皱纹或空洞等结构不完整性，将极大地优化其机械性能。然而，薄膜中紧密堆叠的石墨烯片会降低其离子动力学，从而限制其发展。在此，展示了一种水平 - 纵向结构调制策略来制备具有增强机械、导电和电容性能的石墨烯薄膜。通常，二维大尺寸石墨烯片（LGS）在组装过程中诱导氧化石墨烯（GO）规则堆叠以减少皱纹，而一维单壁碳纳米管（SWCNT）与石墨烯片桥接以加强多方向插层并减少GO层的重新堆叠。同时引入LGS和SWCNT通过改善石墨烯片的排列、增加连续导电通路以促进电子传输以及扩大层间距以促进电解质离子扩散，协同创造出精细的微观结构。结果，所获得的石墨烯薄膜平整，与原始rGO薄膜相比，作为超级电容器电极表现出显著增强的机械性能、电导率（38727 S m）以及比电容（232 F g）。此外，由于性能的全面提升，由基于石墨烯薄膜的电极组装的柔性凝胶超级电容器表现出高能量密度、良好的柔韧性和出色的循环稳定性（10000次循环后电容保持率为93.8%）。这项工作为制造用于柔性和可穿戴电子设备储能应用的坚固石墨烯结构材料提供了一种通用策略。
