DEVELOPMENT OF QUINONE-POSITIVE ELECTRODE MATERIALS FOR AQUEOUS RECHARGEABLE ZINC-ION BATTERIES

Abstract

The ongoing acceleration of climate change experienced over recent years, driven by increased greenhouse gas emissions, has motivated the development of sustainable energy technologies. The power sector, currently responsible for approximately 40% of the global emissions, needs to undergo a decarbonization process to reduce global emissions. While renewable energy sources, such as wind and solar, are increasing their integration into the grid, they depend on variable climate conditions. Consequently, they necessitate the development of stationary energy storage systems for mitigating the intraday fluctuations of power production. For this purpose, aqueous rechargeable zinc-ion batteries are an attractive option due to the safety of their aqueous electrolyte and the abundance of non-toxic zinc. Regardless of the extensive research around zinc-ion batteries, they still face technological challenges, particularly in the development of high-performing cathode materials.

This thesis addresses this challenge through the investigation of the performance and working mechanisms of organic cathode materials within zinc-ion batteries. The research here developed identified three organic materials with theoretical capacities above 170 mAh/g, which were reached during the initial cycles of battery cycling. Additionally, one material tested in this work exhibited an enhanced capacity retention compared to other cathode materials, reaching a high value of 83% after 100 cycles, and ex-situ characterization showed the reversible intercalation of ions in its crystal structure. This work contributes to enhancing the performance and reliability of zinc-ion batteries for stationary energy storage applications. Furthermore, the scientific insights generated in this work contribute to the ongoing scientific questions regarding the energy storage mechanisms of organic cathode materials and their degradation processes.