Abstract Developing lithium ion capacitors (LICs) with high energy density is still challenging, due to the kinetic mismatch between the capacitor-type cathode and the battery-type anode. In addition, metal-free LICs are preferred over high-cost and unsustainable metal-containing electrode materials. Exploring appropriate metal-free cathode and anode materials with high capacity and excellent rate performance is one of the keys to attain such goal. Herein, nanoarchitectured graphene-based LICs are successfully constructed by using 2D polydopamine-graphene heterostructured anode and porous graphene cathode. The 2D nature of polydopamine-graphene facilitate the transport of electrolyte ions while graphene promotes electron transfer. The high specific surface area of the porous graphene endows ions with accessibility and fast transport. The metal-free LIC device achieves a high energy density (135.6 Wh kg−1 at 210.4 W kg−1), high power density (21.0 kW kg−1 at 78.9 Wh kg−1), high low-temperature performance (76.4 Wh kg−1 at −20 °C), and reasonably long cycling life. This work provides an effective strategy to design metal-free LIC with high performance at wide temperature range.

中文翻译：

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基于纳米结构聚多巴胺/石墨烯复合阳极和多孔石墨烯阴极的锂离子电容器

摘要 由于电容器型阴极和电池型阳极之间的动力学不匹配，开发具有高能量密度的锂离子电容器 (LIC) 仍然具有挑战性。此外，与高成本和不可持续的含金属电极材料相比，无金属 LIC 更受欢迎。探索合适的具有高容量和优异倍率性能的无金属正极和负极材料是实现这一目标的关键之一。在此，通过使用二维聚多巴胺-石墨烯异质结构阳极和多孔石墨烯阴极成功构建了基于纳米结构石墨烯的 LIC。聚多巴胺-石墨烯的二维性质促进电解质离子的传输，而石墨烯促进电子转移。多孔石墨烯的高比表面积赋予离子可接近性和快速传输。无金属 LIC 器件实现了高能量密度（210.4 W kg-1 时为 135.6 Wh kg-1）、高功率密度（78.9 Wh kg-1 时为 21.0 kW kg-1）、高低温性能（76.4 Wh kg-1 at -20 °C)，以及相当长的循环寿命。这项工作为设计在宽温度范围内具有高性能的无金属 LIC 提供了一种有效的策略。