Abstract Supercapacitors are widely concerned because of their fast charging and discharging speed, low cost and long operation time. N-doped porous hollow carbon nanotubes (N-PHCN) are widely used as electrode materials for supercapacitors because of their proper length–diameter ratio, high specific surface area from porous structures, good conductivity and high chemical stability. Herein, an in situ activation method for preparing N-PHCN with manganese dioxide nanorods as the core and resorcinol–formaldehyde resin as the carbon precursor was proposed by using the adsorption of KNO3 in resin and its activation on carbon skeleton. Different from the previous activation strategies of porous carbon, this KNO3 in situ activation method can provide regular morphology for carbon materials. In addition, an appropriate amount of activator can lead to a high specific surface area, which ensures its high performance as a supercapacitor for energy storage. The optimized N-PHCN shows a maximum specific surface area of 1312.9 m2 g−1 with a high specific capacitance of 283 F g−1 at a current density of 0.5 A g−1, an energy density of 12.5 Wh kg−1 at a power density of 247.9 W kg−1 and excellent cycle ability with capacitance retention rate of 94.7 after 10,000 cycles.
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机译：摘要 超级电容器具有充放电速度快、成本低、运行时间长等优点，受到广泛关注。N-PHCN掺杂多孔空心碳纳米管（N-PHCN）具有长径比、多孔结构比高、导电性好、化学稳定性高等优点，被广泛用作超级电容器的电极材料。本文提出了一种以二氧化锰纳米棒为核心，以间苯二酚-甲醛树脂为碳前驱体，利用KNO3在树脂中的吸附及其在碳骨架上的活化方法制备N-PHCN。与以往多孔碳的活化策略不同，这种KNO3原位活化方法可以为碳材料提供规则的形貌。此外，适量的活化剂可以产生高比表面积，从而确保其作为储能超级电容器的高性能。优化后的N-PHCN在0.5 A g−1的电流密度下，最大比表面积为1312.9 m2 g−1，比电容为283 F g−1，能量密度为12.5 Wh kg−1，功率密度为247.9 W kg−1，循环后电容保持率为94.7%，循环能力强。
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