蟹壳基氮/氧共掺杂多孔炭的原位制备及其超级电容器性能

采用废弃蟹壳为碳源,KOH为活化剂原位制备了氮/氧共掺杂多孔炭,并研究其作为电极材料在超级电容器中的应用。 固定蟹壳与KOH的质量比为5:3,考察了煅烧温度对所得炭材料产率、孔结构和氮氧含量的影响。 结果表明,蟹壳基炭材料的孔结构和氮/氧含量可通过改变煅烧温度调变。 随着煅烧温度从500 ℃上升至700 ℃,多孔炭的比表面积和孔体积逐渐增大,而氮/氧含量随温度升高则降低。 采用循环伏安和恒流充放电对所得材料的电化学性能进行测试。 结果表明,所得多孔炭的电化学性能取决于其孔结构与氮/氧表面性质的协同作用,其中煅烧温度为600 ℃所得的多孔炭比表面积为612 m²/g,氮和氧含量分别为3.53%和32.8%,在50 mA/g的电流密度下比电容达到310 F/g,循环1000次比电容仍然保持95%以上,展现出良好的电化学性能。

In situ Synthesis of Nitrogen/Oxygen Co-doped Porous Carbons Derived from Crab Shells and Their Application as Supercapacitor Electrode Materials

Nitrogen/oxygen co-doped porous carbons were prepared for supercapacitor electrode using waste crab shells as the carbon source and KOH as the activated agent. The effects of the pyrolysis temperature on the yield, the porous structures and the nitrogen/oxygen content of the obtained carbons were investigated with the fixed mass ratio of crab shells and KOH as 5:3. The results show that the specific surface area and pore volume of the as-synthesized carbons are increased, while their nitrogen/oxygen contents are decreased when the pyrolysis temperature is increased from 500 to 700 ℃. Electrochemical behaviors were determined using cyclic voltammetry and galvanostatic charge-discharge measurements. The results demonstrate that the nitrogen/oxygen content and the porosity of the carbons have important effects on their electrochemical performances. The sample with the pyrolysis temperature fixed at 600 ℃ exhibits the specific surface area of 612 m²/g, the nitrogen content of 3.53% as well as the oxygen content of 32.8%. Its specific capacitance reaches 310 F/g at the current density of 50 mA/g and exhibits the long-term stability with 95% capacitance retention after 1000 cycles. It is obvious that the porous structure and the nitrogen/oxygen contents of the obtained carbons can be controlled by adjusting the pyrolysis temperature, and their electrochemical performances depend on the synergistic effects of the porosity and the surface properties.