Improvement on electrochemical performance by electrodeposition of polyaniline nanowires at the top end of sulfur electrode

Abstract

Herein, we introduce a modification of the sulfur electrode by electrodepositing a covering layer of polyaniline nanowires at the top end for Li–S batteries. The as-fabricated electrodes are evaluated via SEM, FTIR, EDAX, EIS, CV and charge–discharge tests. The SEM images combined with FTIR spectra show that the surface of the electrode is covered by the PANI nanowires. The charge–discharge tests of PANI-5 display the best cyclic performance, delivering the initial discharge capacity of 1304mAhg−1, and 725mAhg−1 after 100 cycles at the current density of 320mAg−1. The CV results of the PANI-5 present an overlapping of cathodic/anodic peaks, indicating that the suitable mass of PANI coating can increase the reversibility of the electrode. SEM combined with EDAX tests of the electrodes after cycles show that the sulfur species are trapped by the PANI nanowires. These results demonstrate that the PANI covering layer plays a barrier to restrain the dissolution of the polysulfides, and provide spaces as well as conductive media for sulfur species.