不同碳气凝胶导电剂对Li-MnO_2电池性能的影响

Effects of Different Carbon Aerogel Conductive Agents on Performance of Li-MnO_2 Battery

以间苯二酚、甲醛为前驱体,通过溶胶凝胶法,采用CO2超临界干燥、冷冻干燥、常压干燥制备碳气凝胶.采用N2低温吸脱附法、四探针法、扫描电镜对碳气凝胶的电导率、孔结构等进行考察,研究碳气凝胶作为导电剂材料对锂-二氧化锰电池大电流放电性能的影响.结果表明:不同干燥方法制备的碳气凝胶电阻率相近,比表面积差异较大,CO2超临界干燥制备的碳气凝胶比表面积最大(1 017.85 m2/g);以CO2超临界干燥制备的碳气凝胶为导电剂的电池放电比容量最大,100 m A恒流放电比容量达到101 m Ah/g,其放电平台比常压干燥的碳气凝胶高80 m V左右,1 m A恒流放电比容量则差异较小.结果显示碳气凝胶导电剂比商业乙炔黑导电剂性能更优.

Carbon aerogel was prepared by means of the sol-gel method from resorcinol and formaldehyde through C02 supercritical drying, freeze drying and ambient drying, and the resistivity and pore structure of the product were characterized via N2 low-temperature adsorption desorption, four-probe method and SEM. Moreover, the in- fluence of carbon aerogel conductive agent on the high-rate discharge performance of Li-Mn02 battery was investiga- ted. The results indicate that （ 1 ） the carbon aerogels produced via different drying methods are of similar resistivity but distinctly different specific surface areas; （2） the carbon aerogel prepared via CO2 supercritical drying posse- sses the highest specific surface area （ 1017.85 m2/g） and the largest constant-current specific discharge capacity （101 mAh/g at a current of 100mA） ; （3） the voltage plateau of the carbon aerogel prepared via C02 supercritical drying is 80 mV higher than that prepared via ambient drying; and （4） there is little difference in the 1 mA dis- charge capacity of different carbon aerogels. All these above-mentioned statements show that carbon aerogel con- ductive agents possess higher performance than the commercial acetylene black.