聚苯胺包覆蛋白石页岩/硫复合材料的制备及其电化学性能

Preparation and Electrochemical Property of Polyaniline Coated Opal Shale/Sulfur Composite

以蛋白石页岩为载硫体,通过化学沉积法制备蛋白石页岩/硫复合材料,再利用化学氧化聚合法在其表面包覆一层聚苯胺,制备出一种新型的蛋白石页岩/硫–聚苯胺复合材料,作为锂硫电池的正极材料。SEM、TEM和BET等测试结果表明蛋白石页岩呈层状多孔结构,小尺寸硫在材料内分布均匀,聚苯胺包覆的厚度约为400 nm。电化学性能测试表明,蛋白石页岩/硫–聚苯胺正极活化后放电比容量最高达到1164.93 m Ah/g,在0.5C(1.0C=1675 m A/g)倍率下,循环300次后放电比容量为539.30 m Ah/g,库伦效率始终保持在95%以上,说明蛋白石页岩具有良好的吸附性,同时导电聚苯胺包覆层具有双效固硫的作用,有利于吸附多硫化物和抑制穿梭效应。

Opal shale/S composite was prepared by loading sulfur on opal shale via solution-based reaction-deposition method, and then polyaniline（PANI） was covered on the as-prepared opal shale/S composite by means of chemical oxidative polymerization method, which was used as cathode material of lithium-sulfur battery. Scanning electron microscope（SEM）, transmission electron microscope（TEM）, and Brunauer-Emmett-Teller（BET） characterization were conducted, and the results indicated that opal shale had a layered porous structure. As-prepared sulfur with small size was distributed uniformly in the composite. The PANI with around thickness of 400 nm was coated on the surface of the opal shale/S composite. Constant current charge-discharge tests showed that opal shale/S-PANI cathode obtained a maximum discharge specific capacity of 1164.93 m Ah/g after activation and retained a discharge specific capacity of 539.30 m Ah/g after 300 cycles at the current rate of 0.5 C（1.0 C=1675 m A/g）. The coulombic efficiency of opal shale/S-PANI cathode always maintained more than 95%, indicating that opal shale with excellent adsorption properties and conductive PANI coating had double fixation effect for sulfur, which was beneficial to adsorb polysulfide and inhibit the shuttle effect.