Designing suitable anode materials with high pseudocapacitance is crucial to achieve high energy density, power density and long cycle life in sodium-ion supercapacitors (SISs). Due to abundant pseudocapacitive reaction sites, good electric conductivity and structural stability, heteroatom-doped carbonaceous electrode materials provide great potential to meet these demands mentioned above. But even though possessing high heteroatom content, the carbonaceous bulk materials with undesired structure still suffer from inferior capability owing to inefficient utilization of these pseudocapacitive sites for sodium-ion storage. In this work, we report a simple but effective strategy to synthesize rich nitrogen-doped carbon on carbon nanotubes (N–C@CNTs) which possesses large surface area with a large number of mesopores and micropores. The massive introduction and retention of nitrogen heteroatoms (12 at.%) can improve electrode wettability, sodium ion absorption by generating extrinsic defects. Identified by kinetics analysis, furthermore, the nanocable construction can promote the kinetics of sodium ions and electronic conductivity to a large extent. Coupling a N–C@CNTs anode with a carbon cathode, a sodium-ion supercapacitor exhibits high energy and power density as well as capacity retention.

设计具有高拟电容的合适阳极材料对于在钠离子超级电容器（SIS）中实现高能量密度，功率密度和长循环寿命至关重要。由于大量的假电容反应位点，良好的导电性和结构稳定性，掺杂杂原子的碳质电极材料提供了巨大的潜力来满足上述这些要求。但是，尽管具有高杂原子含量，但由于对钠离子存储的这些假电容位的利用不充分，具有不希望的结构的碳质散装材料仍具有较差的性能。在这项工作中，我们报告了一种简单而有效的策略，即在具有大表面积，大量中孔和微孔的碳纳米管（NC-CNT）上合成富氮的碳。大量引入和保留氮杂原子（12 at。％）可以通过产生外部缺陷来改善电极的润湿性和钠离子吸收率。此外，通过动力学分析确定，纳米电缆构造可以在很大程度上促进钠离子的动力学和电子传导性。钠离子超级电容器将N–C @ CNTs阳极与碳阴极耦合，具有高能量和功率密度以及容量保持能力。