Chen Huqiang, Chen Songbo, Zhang Yujin, Ren Hao, Hu Xinjun, Bai Yongxiao
Graphene Institute of Lanzhou University-Fangda Carbon, MOE Key Laboratory for Magnetism and Magnetic Materials, Key Laboratory of Special Function Materials and Structure Design of Ministry of Education, Lanzhou University, Lanzhou 730000, China.
ACS Appl Mater Interfaces. 2020 Dec 16;12(50):56319-56329. doi: 10.1021/acsami.0c16976. Epub 2020 Dec 6.
Rational engineering and simplified production of printable graphene inks are essential for building high-energy and flexible graphene micro-supercapacitors (MSCs). However, few graphene-based MSCs show impressive areal capacitance and energy density, especially based on additive-manufacturing, cost-effective, and printable inks. Herein, a new-style and solution-processable graphene composite ink is ingeniously formulated for scalable screen printing MSCs. More importantly, the as-formulated inks consist of interwoven two-dimensional graphene and activated carbon nanofillers, which are delaminated by one-step sand-milling turbulent flow exfoliation. Notably, embedding the activated carbon nanoplatelets into graphene layers drastically boosts the electrochemical performance of screen-printed micro-supercapacitors (denoted as Gr/AC-MSCs), such as an outstanding areal capacitance of 12.5 mF cm (about 20 times than pure graphene). The maximum energy density, maximum power density, and exceptional cyclability are 1.07 μW h cm, 0.004 mW cm, and 88.1% after 5000 cycles, respectively. As such, the as-printed MSCs on paper display high resolution and pronounced energy-storage performance. Furthermore, the packaged and optimized Gr/AC-MSCs showcase remarkable mechanical flexibility even under highly folded and excellent water resistance, maintaining 91.8% capacitance retention after being washed for 90 min. The versatile methodology highlights the promise of graphene and analogous 2D nanosheet functional inks for scalable fabrication of flexible energy-storage devices.
合理设计并简化可印刷石墨烯油墨的生产工艺，对于制造高能量、柔性的石墨烯微型超级电容器（MSC）至关重要。然而，很少有基于石墨烯的微型超级电容器能展现出令人印象深刻的面积电容和能量密度，特别是基于增材制造、具有成本效益且可印刷的油墨。在此，一种新型且可溶液加工的石墨烯复合油墨被巧妙地调配出来，用于可扩展的丝网印刷微型超级电容器。更重要的是，所调配的油墨由交织的二维石墨烯和活性炭纳米填料组成，通过一步砂磨湍流剥离使其分层。值得注意的是，将活性炭纳米片嵌入石墨烯层极大地提升了丝网印刷微型超级电容器（记为Gr/AC-MSCs）的电化学性能，例如具有12.5 mF/cm²的出色面积电容（约为纯石墨烯的20倍）。在5000次循环后，最大能量密度、最大功率密度和出色的循环稳定性分别为1.07 μW h/cm²、0.004 mW/cm²和88.1%。因此，在纸上印刷的微型超级电容器具有高分辨率和显著的储能性能。此外，经过封装和优化的Gr/AC-MSCs即使在高度折叠的情况下也展现出卓越的机械柔韧性和出色的耐水性，在清洗90分钟后电容保持率为91.8%。这种通用方法突出了石墨烯及类似二维纳米片功能油墨在可扩展制造柔性储能器件方面的前景。
