Two Cathodes in One for Lithium‐Ion Batteries: Voltammetric Study of a Composite Cathode of Sulfur and LiFePO4

• Published in: ChemistrySelect (Weinheim) 2020-05, Vol.5 (20), p.6172-6177
• Main Authors: David Garay‐Marín, Juan, Quiroga‐González, Enrique, Leticia Garza‐Tovar, Lorena
• Format: Article
• Language: English
• Subjects: Composite cathode; Electrochemistry; Hydrothermal synthesis; Lithium-Sulfur battery; Two cathodes in one
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202001292

In order to satisfy the growing energy demand of large‐scale applications such as energy storage for renewable sources and for electromobility, advanced electroactive materials are required for energy storage technologies. The aim of this work is to develop a new cathode concept for Li‐ion batteries, which allows high charging/discharging rates as well as high gravimetric capacities. The composite cathode consisting of LiFePO4 (high rates) and S (high capacity), takes advantage of the benefits of both materials. However, it is a challenge considering the reactivity of both materials, and the electrolytes needed for each of them. This paper deals with some strategies to make the composite work; the problems encountered when having two materials with different electrochemical behavior in the same electrode in a battery have been partially solved. The voltammetric studies of this work show promising results for the development of the new concept of lithium‐ion batteries. This is the first reported combination of active materials of high capacity (sulfur) and high charging rate (LiFePO4) as a single cathode for Li ion batteries. The combination of cathode materials has been enabled by hindering the reaction between them. For this purpose, an alternative hydrothermal carbonization process has been developed to coat LiFePO4 with carbon, which avoids its chemical or thermal decomposition.