Poly(vinylidene chloride)based carbon as an electrode material for high power electric double layer capacitors
-
摘要: 在600℃～1100℃对聚偏二氯乙烯（PVDC）树脂仅进行炭化处理，制备了一系列PVDC基活性炭。由TG、XRD和N2吸附等温线(77 K)分别测定了PVDC基炭经历的热解过程与其晶型、比表面积和孔结构；采用循环伏安、交流阻抗和恒电流充放电考察了它们在质量分数30%的 KOH水溶液中的电容特性。结果表明：PVDC基炭属于无定形碳，其大的比表面积（874.5m2/g～969.2m2/g）和丰富的微孔在固相炭化过程中形成；PVDC基炭具有适于双电层形成的优异孔径分布、高的质量比电容和面积比电容；900℃炭化的PVDC基炭具有最高的比电容值和良好的功率特性，50mA/g电流密度时的放电比电容达256.9F/g，5000mA/g电流密度时的放电比电容保持率达76.5%；提高炭化温度可提高PVDC基炭的电导率，降低电解质离子在孔内的扩散阻抗，改善双电层电容器的功率性能。Abstract: A series of poly vinylidene chloride (PVDC) based activated carbons was prepared by carbonization at 600-1100℃. Their formation , crystallinity, surface area and pore structure were characterized by thermogravimetry, X-ray diffraction and nitrogen adsorption. The electrochemical performance was investigated by cycle voltammetry, AC impedance and galvanostatic charge/discharge in a 30 wt. % KOH electrolyte. Results showed that the structure of PVDC-based carbons was amorphous and their high surface area (874-969 m2/g) and abundant micropores were formed during the solid phase carbonization. PVDC-based carbon had a high gravimetric capacitance and specific capacitance per surface area, owing to its optimum pore size distribution suitable for the formation of electric double layers. The PVDC-based carbon heat-treated at 900℃ had a maximum capacitance and an excellent power performance. The specific capacitance can reach as high as 256.9F/g at low discharge current density (50mA/g) and the capacitance retention ratio is 76.5% at high current density (5 000mA/g). The electrical conductivity of PVDC-based carbon increased and the diffusion resistance of electrolyte ions in pores decreased with increasing carbonization temperature, and the rate performance of the electric double layer capacitor is improved as a result
-
Key words:
- Electrochemical double layer /
- Poly(vinylidene chloride) /
- Ion size /
- Pore structure
-
点击查看大图
计量
- 文章访问数: 2041
- HTML全文浏览量: 96
- PDF下载量: 1271
- 被引次数: 0
下载:
