Fiber-shaped supercapacitors are attractive as an energy storage unit due to their excellent flexibility. However, fabricating robust fibers with large yields remains a challenge. In this work, we prepare flexible core-sheath fibers via coaxial extrusion printing. Carboxymethylcellulose sodium salt (CMC) slurry with controlled rheological properties is extruded from the outer channel, while the graphene oxide (GO) slurry is extruded from the inner channel simultaneously. The followed freeze-drying process protects GO sheets from agglomeration, providing more efficient chemical reduction. The reduced GO (rGO) sheets are separated and expanded to fill in the CMC sheath, which eliminates the delamination between the CMC sheath and rGO core. We study the influences of the freeze-drying process on the fiber microstructures, and explore the slurry design, fiber quality, reduction condition, and electrochemical performance. The fabrication method allows scalable manufacturing of the core-sheath electrodes and fiber-shaped supercapacitors with more efficient conductive networks.
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机译：纤维形超级电容器因其出色的柔韧性而作为储能单元具有吸引力。然而，制造具有高产量的坚固纤维仍然是一个挑战。在这项工作中，我们通过同轴挤出印刷制备了柔性芯护套纤维。具有可控流变性能的羧甲基纤维素钠盐（CMC）浆料从外通道挤出，而氧化石墨烯（GO）浆料同时从内通道挤出。随后的冷冻干燥工艺可防止 GO 板材结块，从而提供更有效的化学还原。减少的 GO （rGO） 片被分离并膨胀以填充 CMC 护套，从而消除了 CMC 护套和 rGO 芯之间的分层。研究了冷冻干燥工艺对纤维微观结构的影响，并探讨了浆料设计、纤维质量、还原条件和电化学性能。这种制造方法允许可扩展地制造具有更高效导电网络的磁芯护套电极和纤维形超级电容器。
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