Effect of cross-linking on electrochemical performances of polyaniline as the cathode material of lithium-ion batteries

Developing advanced organic cathodes with significant charge–discharge performances would prove a potential alternative for traditionally inorganic cathode materials of lithium-ion batteries in the future. Herein, a conductive polymer as electrode with improved electrochemical performances was reported. Polyaniline (PANI) with fibrous morphology was firstly polymerized by using perchloric acid (HClO) as the large molecular doped acid. Furthermore, the cross-linking PANI was prepared with using triphenylamine as the cross-linkers and p-phenylenediamine as the molecular chain extender. Applied as the cathode of lithium-ion batteries, the cross-linking PANI fibers with moderate cross-linking degree exhibited an improved electrochemical and cell performances, in which it presented a highest discharge specific capacity of 138.5 mAh·g and a relatively stable capacity retention of around 126.3 mAh·g after 150 cycles. Also, the cross-linking PANI exhibited the improved rate capabilities, and it could still provide a discharge specific capacity of 92.5 mAh·g even at a higher current density of 500 mA.g, which is obviously higher than that of pure PANI. The work presented herein demonstrated that the cross-linking for conductive polymers was a potential way to obtain the improved electrochemical performances for the polymer-based electrode material.