用于锂离子电池正极材料的分级孔碳/2,5-二巯基-1,3,4-噻二唑/聚噻吩三元复合物

采用酚醛树脂为碳源, 纳米碳酸钙为二次成孔剂, 通过煅烧、刻蚀、KOH活化等工艺制备出活化分级孔碳(aHPC). 在此基础上, 以aHPC为模板, 通过溶液浸渍制得活化分级孔碳/2,5-二巯基-1,3,4-噻二唑(aHPC/DMcT)复合物, 然后运用氧化聚合法将聚(3,4-乙烯二氧噻吩)—聚苯乙烯磺酸(PEDOT-PSS)包覆在其表面制备出aHPC/DMcT/PEDOT-PSS复合物. 并运用傅里叶变换红外(FTIR)光谱、X射线衍射(XRD)、场发射扫描电镜(FESEM)、透射电镜(TEM)和电化学测试等手段对所得复合材料的结构、形貌及电化学性能进行表征. 结果显示, KOH活化后, aHPC孔道内的官能基团含量增加了, 使得DMcT的负载量增大(52%), 且DMcT几乎全部进入到aHPC孔道内. aHPC/DMcT复合物的首次放电容量为236 mAh·g^-1, 循环20次后放电比容量仅为65mAh·g^-1. 而aHPC/DMcT/PEDOT-PSS复合物的表面包覆一层PEDOT-PSS导电薄膜, 其首次放电容量高达281 mAh·g^-1, 20次后的放电比容量为138 mAh·g^-1,容量保持率达49.1%.

Hierarchically Porous Carbon/DMcT/PEDOT-PSS Ternary Composite as a Cathode Material for Lithium-Ion Battery

Activated hierarchically porous carbon (aHPC) was fabricated by calcination, etching and KOH activation using phenol-formaldehyde resin (PF) as the carbon precursor and nano-CaCO₃ dispersion as the double pore-forming agent. On this basis, the aHPC/2,5-dimercapto-1,3,4-thiadiazole (DMcT) composite was prepared through a solution immersion method using aHPC as the substrate, and poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonate) (PEDOT-PSS) was coated subsequently onto the surface of aHPC/DMcT by in situ oxidative polymerization to prepare the aHPC/DMcT/PEDOT-PSS composite. The structure, morphology, and electrochemical properties of the composite were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and electrochemical measurements. The results showed that the amount of the functional groups in aHPC pores increased after HPC was activated by KOH, resulting in an enhancement (52%) of the adsorption of DMcT. Moreover, almost all of the DMcT was absorbed into the aHPC pores. It was found that the initial discharge capacity of the aHPC/DMcT composite was 236 mAh·g^-1 and its specific capacity remained at 65 mAh·g^-1 after 20 cycles. For comparison, with a surface coated with a layer of PEDOT-PSS conductive film, the initial discharge capacity of the aHPC/DMcT/PEDOT-PSS composite was up to 280 mAh·g^-1 and it remained at 138 mAh·g^-1 after 20 cycles (49.1% capacity retention).