The preparation of three-dimensional binder-free polyaniline/aligned carbon nanotube on flexible etched Al foil substrate as high-performance pseudocapacitive cathode for nonaqueous lithium-ion capacitor

Abstract

In this work, 3D binder-free polyaniline (PANI)/aligned carbon nanotube (ACNT) nanocomposite arrays on flexible etched Al foil with strong bonding strength is developed as a high-capacity pseudocapacitive cathode material in a non-aqueous electrolyte for lithium ion capacitors (LICs). The optimized PANI/ACNT nanocomposite with a rational 3D pore structure facilitates the ion transportation and fully utilizes the synergistic effect between PANI and ACNTs to improve capacitive performance substantially. The as-prepared nanoscale PANI demonstrates a specific capacity of 325.2 F•g−1 (180.7 mAh•g−1) at 0.5 A•g−1 in the non-aqueous lithium-ion electrolyte and achieves excellent rate performance and cycling stability (retains 95.6% after for 5,000 cycles charge-discharge at 1 A•g−1 in Li-half cell). Furthermore, when matched with a lithium titanate (Li4Ti5O12) anode, the nanoscale PANI delivers a superior specific energy of 295.3 Wh•kg−1 at the specific power of 125.1 W•kg−1. The as-fabricated LIC delivers a specific energy of 49.6 Wh•kg−1 at the specific power of 21.0 W•kg−1 and successfully retains 39.1 Wh•kg−1 at 480.5 W•kg−1. Moreover, the as-fabricated LIC exhibits an excellent capacity retention of 86.8% after 1,000 cycles at 2 A•g−1. The results verify that the as-prepared PANI/ACNTs/etched Al foil is a promising pseudocapacitive cathode material for high-performance LIC application.