反相乳液法无乳化剂制备炭微米球及其电化学性能

Preparation of carbon microspheres by inverse emulsion polymerization and their electrochemical performance as electrode materials of supercapacitors

以酚醛树脂的乙醇溶液为原料,导热油和硅油混合油为油相,在不添加任何乳化剂的情况下,采用反相乳液法制得酚醛树脂微米球。重点考察了合成条件对树脂成球的影响,并探讨了体系的成球机制。结果表明,引入黏度低、导热性能好、可与酚醛树脂形成强π-π相互作用的导热油对合成树脂微球起关键作用。混合油质量比、酚醛和乙醇配比及搅拌速度在较宽范围内变化时,制得的酚醛树脂微球经800℃炭化均能获得球形度良好的炭微米球。优化条件下（导热油和硅油质量比为4：1,乙醇和酚醛质量比为4：1,搅拌速度为2 000 r/min）,可获得球形度好、尺寸分布较窄的炭微米球（5~20μm）。该球经KOH活化后,当电流密度为1 A/g时,比电容可达206 F/g,电流密度为20 A/g时,比电容仍然保持在134 F/g。这些优异的电化学性质归因于炭球高的比表面积和合适的孔道结构。

Porous phenolic resin- based carbon microspheres were prepared by inverse emulsion polymerization,followed by carbonization at 800 ℃ for 1 h and KOH activation at 800 ℃ for 1 h with a KOH/coke mass ratio of 4.Thermal setting phenolic resin in ethanol was used as one phase and a mixture oil of silicone oil and heat transfer oil as the other phase in the inverse emulsion polymerization.The performance of the porous spheres as electrode materials in supercapacitors was investigated.Results indicate that the size and morphology of the spheres are mainly determined by the mass ratio of silicone oil to heat conduction oil,the mass ratio of alcohol to phenolic resin and the stirring speed.The heat transfer oil with alkyl benzene size chains interacts with phenolic resin by a π-π interaction,which is beneficial for the formation of microspheres.The porous spheres prepared under the optimum conditions have a high specific capacitance of 206 and 134 F/g at current densities of 1 A/g and 20 A/g,respectively in a 6 M KOH electrolyte.The good capacitive and rate performance can be ascribed to the high specific surface area and the pore structures.