铜箔集流体表面聚苯胺复合改性研究

Modification of polyaniline on surface of copper foil fluid collector

通过恒压法电化学聚合方式,在铜箔表面形成导电聚苯胺(PANI)薄膜,制备了复合铜箔集流体(PANI/Cu)。扫描电镜(SEM)测试结果表明,铜箔集流体表面的聚苯胺主要由200 nm尺寸大小的颗粒构成,聚苯胺颗粒之间结合紧密,在铜箔表面形成均匀的层状结构。傅里叶红外变换光谱(FT-IR)和紫外分析(UV-Vis)结果表明PANI主要以混合型导电结构形式存在。以锂片为正极,LiTiO为负极,改性铜箔作负极集流体组装纽扣电池,恒流充放电试验表明:在1C倍率循环500圈后,基于PANI/Cu复合集流体构建的Li|LiTiO电池放电比容量为164.6 mAh·g,而无改性的铜箔集流体(Bare/Cu)构建的电池放电比容量只有155.6 mAh·g;当倍率提高至10C时,PANI/Cu复合集流体构建的电池循环1000圈后容量保持率为80%,而Bare/Cu集流体构建的电池容量保持率仅为60%。进一步分析认为,聚苯胺的改性提高了铜箔与LiTiO的界面兼容性,降低了电池界面阻抗,从而有效提高电池的电化学性能。

A composite copper foil collector(PANI/Cu) was prepared by forming a conductive polyaniline film on the surface of the copper foil by constant pressure method electrochemical polymerization. Scanning electron microscope(SEM) test results show that the polyaniline on the surface of the copper foil collector mainly consists of the particles with the size of 200 nm, and the polyaniline particles are tightly bound to each other, which forming a uniform layer structure on the surface of the copper foil. Fourier-infrared(FT-IR) and ultraviolet(UV-Vis) analysis results indicate that PANI exists mainly in the form of hybrid conductive structure. Using lithium sheet as the positive electrode, LiTiOas the negative electrode and modified copper foil as the negative collector, the button battery was assembled. The constant current charge/discharge test shows that the discharge specific capacity of the battery is 164.6 mAh·gafter 500 cycles at 1 C magnification, while the discharge capacity of the battery constructed with unmodified copper foil collector(Bare/Cu) is only 155.6 mAh·g. When the current density is increased to 10 C, the capacity retention of the battery constructed with PANI/Cu composite collector is 80% after 1000 cycles, while the capacity retention of the battery constructed with Bare/Cu collector is only 60%. It is concluded that the modification of polyaniline improves the interfacial compatibility of the copper foil with LiTiOand reduces the interfacial impedance of the battery, thus effectively improving the electrochemical performance of the battery.