间苯二酚/甲醛树脂基高电化学性能炭微球的尺寸控制合成

Synthesis of size-controlled carbon microspheres from resorcinol/formaldehyde for high electrochemical performance

纳米结构酚醛树脂基炭气凝胶具有丰富的网络结构,是理想的超级电容器电极材料。然而,目前已合成出的大多数炭气凝胶为块状材料且其容量较低,制约着其实际应用。本文采用水热法成功地合成出酚醛树脂基多孔炭微球。通过SEM、BET、XPS等多种表征手段,发现铵基数目、烷基链长度和水热温度对炭球的孔结构、尺寸和均匀性有重要的影响。另外,研究还发现前驱体聚合过程中NH_4~+是形成炭球的必要条件,改变参数对多孔炭球的晶体结构无明显影响。将所制备的炭微球作电极材料,在电流密度为1.0 A g~(-1)时,样品CN-80的性能最好,其最高比电容为233.8 F g~(-1)。结果表明,炭材料大的比表面积、孔隙率和缺陷可能是提高电极电容的关键因素。同时,CN-80在7 A g~(-1)下10 000次充放电循环后,其电容保持率为98%,表明其具有良好的循环稳定性。

Nanostructured phenolic resin-based carbon aerogels with an extensive network structure are regarded as ideal energy storage materials for supercapacitors.However,the initial bulk form and low capacitance of previously reported porous carbon aerogels are problematic for practical use.Phenolic resin-based porous carbon spheres were synthesized by a simple hydrothermal process using ammonia,ethylenediamine or hexylenediamine as a catalyst.The porous carbon spheres were investigated by SEM,BET,XPS,etc.It was found that the number of ammonium groups,length of the alkyl chain and processing temperature play vital roles in determining the pore structure,size and uniformity of the carbon spheres.NH4+is necessary to obtain the carbon spheres and but changing the other parameters has no obvious effect on their crystal structure.The sample prepared at a hydrothermal temperature of80℃using ammonia as the catalyst has the highest specific capacitance of 233.8 F g-1 at a current density of 1.0 A g-1.It has an excellent capacitance retention of 98%after 10000 charge/discharge cycles at 7 A g-1,indicating its good cycling stability and rate capability.This result shows that a higher specific surface area,porosity and defect density are probably the crucial factors in improving the electrochemical capacitance.