Polytriphenylamine Derivative and Carbon Nanotubes as Cathode Materials for High-Performance Polymer-Based Batteries

Abstract

Composites of polytriphenylamine (PTPA), its novel derivative poly(4-carbamoyl-N,N-diphenylaniline-2,2,5,5-tetramethyl-pyrrolin-1-oxyl) (PTPA-PO), and multiwalled carbon nanotubes (CNTs) were synthesized by in situ polymerization. The characterization results showed that the CNTs were homogeneously distributed in the polymer matrix and formed a cross-linked conductive network. The electrical properties of PTPA/CNT composites were better than those of traditional acetylene black as conductive agents. Electrochemical tests showed that the initial specific discharge capacity of the PTPA/CNT composites was 107.6 mAh g–1 (theoretical capacity of PTPA is 109 mAh g–1). Furthermore, further research to increase the specific capacity demonstrated that the as-synthesized polytriphenylamine derivative, PTPA-PO, with a CNT cathode presented two well-defined plateaus and an enhanced discharge capacity of 139.3 mAh g–1. Additionally, the PTPA-PO/CNT electrode showed superior cycling performance and remained above 90% of the initial capacity after 100 cycles. The enhanced electrochemical performance of PTPA-PO was due to its combination of the conducting polymer PTPA and free radical active site pendant PO, which increased its electrochemical reaction rate, and this composite is a promising material for high-performance polymer-based organic batteries.