Design and characterization of low-dimensional electrodes for high-energy-density lithium–sulfur batteries

Abstract

i) low electrical conductivity of elemental sulfur, ii) volume expansion during the electrochemical reaction, and iii) dissolution of lithium polysulfides into the electrolyte. There have been extensive researches to overcome these issues by designing a successful structure of the conductive matrix to incorporate the sulfur species. For the practical use of the Li–S, recently, areal capacity has been in the spotlight, which connotes the aspect of sulfur loading and specific capacity. Securing the high areal capacity significantly contributes to the high energy density of Li–S batteries but is limited by the low sulfur loading amount. In this regard, I have designed and characterized the novel and effective structure of porous sulfur host by utilizing low-dimensional materials such as nanofibers, microtubes, and hollow spheres to accommodate a large amount of sulfur and promote the sulfur utilization directly coupled to the improvement of areal capacity. Starting from the structural design of the conductive scaffold, the research has been developed to characterize the mechanism of Li–S electrochemistry to acquire both high areal capacity and stable cyclability. After accomplishing the high areal capacity, all the designed electrodes were introduced to full cell application with the well-designed lithium anodes to develop the practical potential of Li–S batteries.

High energy density is a prerequisite of advanced energy storage systems for the expanding spectrum of electronic applications over the past decades. Hitherto, lithium–sulfur batteries (Li–S) have been regarded as a promising system to realize the high energy density beyond the state-of-the-art lithium-ion batteries having limited energy density. This is because the Li–S has a high theoretical specific capacity (1675 mAh g−1) and a high theoretical energy density (2500 Wh kg−1 or 2800 Wh L−1) via conversion reaction with multiple lithium ions. However, chronic obstacles hinder the commercialization of the Li–S batteries