以N,N-二甲基二茂铁甲胺与溴代十二烷合成阳离子表面活性剂(甲基二茂铁)十二烷基二甲基溴化铵(FC-DBAB)。用FC-DBAB和十二烷基三甲基溴化铵分别对碳纳米管/硫复合颗粒进行表面改性。利用接触角仪和Zeta电位仪对改性和未改性产品的表面性质进行分析;以改性材料为正极制备组装锂硫电池,并进行电化学性能测试。结果表明,表面改性使碳纳米管/硫复合颗粒表面电负性增大,含有二茂铁基团的表面活性剂改性效果更为显著;改性后的锂硫电池在高倍率下充放电性能更好,二茂铁基团还起到吸附多硫化物、抑制穿梭效应的作用。FC-DBAB-CNTs@S电池在1 C下充放电循环300圈,单圈衰减率为0.1%,比DTAB-CNTs@S电池下降30%。

1-Bromoeicosane and (dimethylaminomethyl)ferrocene are synthesized to (ferrocenylmethyl) dodecyldimethylammonium bromide (FC-DBAB),a cationic surfactant.And carbon nanotubes/sulfur composite particles are modified on their surface with FC-DBAB and dodecyl trimethyl ammonium bromide,respectively.The surface properties of modified and unmodified products are analyzed by means of contact angle meter and Zeta potentiometer.The electrochemical properties of lithium sulfur batteries prepared with modified products as cathode are tested through electrochemical impedance test (EIS),cyclic voltampere test (CV),and charge and discharge performance test.It is found that the surface electronegativity of carbon nanotube/sulfur composite particles increases after surface modification,and the modification effect by surfactant-containing ferrocene group is more significant.The charge-discharge performance of modified lithium-sulfur battery is better than the unmodified one at a high current rate.Ferrocene group also plays the roles of absorbing polysulfide and inhibiting the shuttle effect.the FC-DBAB-CNTs@S battery delivers a capacity decay rate of 0.1% after 300 cycles of charges and discharges at 1 C,which is about 30% lower than DTAB-CNTs@S battery.

曹翔宇(1985-),男,博士,副教授,主要从事新能源材料研究,caoxiangyu@tyu.edu.cn。