Li Jian, Cai Yanjun, Yao Xiang, Zhang Yue, Tian Hualing, Su Zhi
College of Chemistry and Chemical Engineering, Xinjiang Normal University Urumqi 830054 Xinjiang China
Xinjiang Key Laboratory of Energy Storage and Photoelectrocatalytic Materials Urumqi 830054 Xinjiang China.
RSC Adv. 2022 Apr 25;12(20):12377-12382. doi: 10.1039/d1ra08963c. eCollection 2022 Apr 22.
Nitrogen self-doped carbon was synthesized by hydrothermal and microwave calcination using polyacrylonitrile as a carbon source and nitrogen source. This method dramatically reduces the material preparation time while improving the electrochemical performance of amorphous carbon. X-ray photoelectron spectroscopy (XPS) analyses reveal that the pyridine nitrogen content is increased and the graphitized nitrogen disappeared in an amorphous carbon block. This indicates that the nitrogen doping sites of the amorphous carbon block can be modulated by the hydrothermal method. Microscopic observations show that the nitrogen self-doped carbon is nano-carbon spheres and carbon micron block. The self-doped nitrogen micron carbon block exhibits excellent cyclability and ultra-high rate capacity. When cycled at 0.5 A g, the discharge capacity remains 356.6 mA h g after 1000 cycles. Even cycled at 5 A g, the rate capacity was maintained at 183.3 mA h g after 300 cycles. The defects produced by self-doped pyridine nitrogen, not only improved the reactivity and electronic conductivity but also enhanced lithium-ion diffusion kinetics.
以聚丙烯腈为碳源和氮源，通过水热和微波煅烧合成了氮自掺杂碳。该方法显著缩短了材料制备时间，同时提高了无定形碳的电化学性能。X射线光电子能谱（XPS）分析表明，在无定形碳块中吡啶氮含量增加，石墨化氮消失。这表明水热法可以调控无定形碳块的氮掺杂位点。微观观察表明，氮自掺杂碳为纳米碳球和碳微米块。自掺杂氮的微米碳块表现出优异的循环稳定性和超高倍率性能。在0.5 A g的电流密度下循环1000次后，放电容量仍保持在356.6 mA h g。即使在5 A g的电流密度下循环300次后，倍率性能仍保持在183.3 mA h g。自掺杂吡啶氮产生的缺陷不仅提高了反应活性和电子导电性，还增强了锂离子扩散动力学。
