In this paper, a novel material—3D potassium-ion preintercalated graphene—was designed and synthesized via one step using a new reaction between K and CO. Furthermore, this material exhibited excellent performance as electrodes for aqueous symmetrical supercapacitors. When the electrode was scaled up from 3.0 to 8.0 mg/cm², negligible capacitance degradation was observed, leading to a very high areal capacitance of 1.50 F/cm² at 1 A/g. Furthermore, even if a large operating temperature of −15 or 55 °C was employed, its excellent electrochemical performance remained with specific capacitances of 208 F/g at 55 °C, 184 F/g at 25 °C, and 98 F/g at −15 °C. This could be attributed to 3D structure and K⁺ preintercalation of the material, which provides rich active sites for electric double-layer formation, lower ion transport resistance, and shorter diffusion distance.

中文翻译：

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超级电容器用3D钾离子预嵌入石墨烯的设计与合成

在本文中，使用K和CO之间的新反应，一步一步设计和合成了一种新型材料3D钾离子预嵌入石墨烯。此外，该材料作为水对称超级电容器的电极表现出优异的性能。当电极从3.0扩大到8.0 mg / cm ^2时，观察到的电容衰减可忽略不计，从而导致在1 A / g时极高的面积电容为1.50 F / cm ²。此外，即使采用-15或55°C的较大工作温度，其优异的电化学性能仍保持不变，在55°C时的比电容为208 F / g，在25°C时的比电容为184 F / g，98 F / g在-15°C下。这可能归因于3D结构和K ⁺ 预先插入材料，可为双电层形成提供丰富的活性位点，降低离子传输阻力，并缩短扩散距离。