The electrochemical behavior of graphene sheets in energy storage system is closely related to its electronic structures. Specifically, structural vacancy defects can expose more active sites and enhance the electrochemical performance. However, it is still a challenging problem to realize valid defect regulation on improving the reaction kinetics of electrode materials. Herein, vacancy-defective graphene sheets were constructed through the thermal mediated method via intercalation of polyacrylonitrile nanofibers. The vacancy defects were generated from the NH gas resulting from polymer decomposition at gradient carbonization temperature. The obtained composites of the graphene sheets and carbon nanofibers demonstrate that the vacancy defects benefit to charge transport, allowing more electrons to pass through the interlayered structure, and enhance the adsorption capacitance during the reversible electrochemical process. In addition, the as-assembled Zn ion hybrid supercapacitors exhibit a high energy density of 129.9 Wh kg and outstanding cyclic stability (99.8 % after 10,000 cycling). The confined polymer-mediated thermal modification strategy can afford abundant vacancy defective sites and exhibit promising outlook for constructing high-performance graphene-based electrode materials for Zn ion hybrid supercapacitors.

中文翻译：

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聚合物介导的石墨烯片空位缺陷作为水性锌离子混合超级电容器的高性能阴极材料

石墨烯片在储能系统中的电化学行为与其电子结构密切相关。具体来说，结构空位缺陷可以暴露更多的活性位点并增强电化学性能。然而，实现有效的缺陷调控以改善电极材料的反应动力学仍然是一个具有挑战性的问题。在此，通过插入聚丙烯腈纳米纤维的热介导方法构建了空位缺陷石墨烯片。空位缺陷是由聚合物在梯度碳化温度下分解产生的NH气体产生的。所获得的石墨烯片和碳纳米纤维的复合材料表明，空位缺陷有利于电荷传输，允许更多的电子通过层间结构，并在可逆电化学过程中增强吸附电容。此外，组装后的锌离子混合超级电容器具有129.9 Wh kg的高能量密度和出色的循环稳定性（10,000次循环后为99.8%）。受限聚合物介导的热改性策略可以提供丰富的空位缺陷位点，并在构建用于锌离子混合超级电容器的高性能石墨烯基电极材料方面表现出良好的前景。