One-step nonlinear electrochemical synthesis of TexSy@PANI nanorod materials for Li-TexSy battery

Abstract

As a promising cathode material for rechargeable lithium ion batteries, tellurium has attracted a great deal of attention due to its high conductivity and high theoretical capacity. Yet, the large volume expansion (~104 vol%) during Li-Te alloying process prevents the application of Li-Te battery. Here, by using a novel one-step nonlinear electrochemical approach, we prepared a TexSy@polyaniline nanorod composites, in which elemental sulfur is successfully embedded into tellurium matrix to effectively tackle the volumetric variation problem. In situ transmission electron microscopy (TEM) of the Li-Te (de)alloying process on single TexSy@polyaniline particle demonstrated that the volumetric variation was efficiently suppressed in comparison to the situation of pristine Te particles. Moreover, polyaniline binder effectively trapped Te and sulfur species in its network and guaranteed stable electric contact and fast transport of Li ions, which resulted in significant improvement of the battery performance. Interestingly, the as-obtained composites display a high initial capacity of 1141 mA h g−1 with typical Li-S battery characteristics at a low current density of 0.1 A g−1, while it shows a good cycling stability at high current density of 5 A g−1 with Li-Te battery features.