Improving Cycle Stability and Kinetics of Rechargeable Aluminum-CO2 Batteries using Functional Cathode Materials

Abstract

The aluminum-carbon dioxide (Al-CO2) battery has been demonstrated as a rechargeable system capable of delivering high discharge voltage and capacity. Unfortunately, this secondary battery faces challenges with low cycle stability. This work is focused on the enhancement of the Al-CO₂ battery performance through the optimization of gas diffusion electrodes (GDEs). We developed and characterized a novel GDE, designated as KBGR311 GDE, composed of three parts ketjenblack and one part graphene. By implementing high surface area and high conductivity carbon-based materials (ketjenblack and graphene), significant improvements were observed in current density and cycle stability of this battery. The investigation of hydrophobicity and active surface area between cathode-electrolyte interfaces created the fundamental knowledge necessary to optimize material properties, enhance electron mobility, and improve CO2 diffusion. The contact between electrolyte-electrode and the high surface area of the material is crucial to reduce mass transport resistance. Significant improvements were observed in the current density and cycle the stability of the Al-CO2 battery when evaluating the new improved GDE design. During cyclic voltammetry tests, the new GDE demonstrated over five times increased in discharge current density and over four times improvement in cyclability. These results offer valuable insights into material properties and electrode design, demonstrating that the KBGR311 GDE offers a promising advancement optimizing both surface area and CO2 diffusion kinetics for next-generation Al-CO2 battery applications.