Improved Electrochemical Performance By Templating Carbon-Sulfur Composite Electrodes for Lithium-Sulfur Batteries

Abstract

Replacing fossil energy sources by renewable and clean energies is of large importance for decades to come. The mainly electric and intermittent renewables energies require proper electricity storage systems that must be: clean, economical, efficient, long life, safe and have high specific capacities (mass and volume). For Argentina, with its significant reserves of lithium in the north west of the country, developments on lithium-ion battery technology are of paramount importance. Current research in Argentina is carried out to improve future lithium battery prospects. Focus is on development and characterization of new active materials for Li-ion battery electrodes, and on systems beyond Li-ion. Li-S batteries are promising candidates to replace current Li-ion technology. In the case of C-S composite cathodes, there are several factors regarding the composition and structure that affect the performance of the battery. Nonetheless, little is known on how the architecture of the composite electrode influences the electrochemical performance of the battery. The present work consists of a systematic investigation of the influence of two very important factors regarding composite electrode fabrication and cell assembly. The factors that are considered are the electrode architecture, modified by templating, and the electrolyte to sulfur ratio. A full factorial two-by-three experimental design is employed, considering five response variables: the initial and final specific capacity of the sulfur cathode, the specific capacity loss per cycle, as well as the initial and final cell energy density. All battery cells are tested for 100 cycles galvanostatically with a C/10 current. Statistically significant factors and their interactions are identified.