Facile method of preparation of carbon nanotubes based aerogels as cathodes for lithium-oxygen cells

Lithium oxygen cells (Li-O2 cells) are considered one of the most promising solutions to the constantly growing demand for energy storage capacity, mainly in the electric vehicle and industrial energy storage sectors, due to their extremely high energy density resulting from the semi-open system in which these cells operate, and the type of reactions taking place during discharging and charging (ORR and OER, respectively). However, potential of the Li-O2 cell is heavily limited by the sluggish kinetics of electrode reactions and the possible side reactions occurring during the work of the cell. The development of an effective cathode is one of the possible solutions to address this challenge. Carbon nanotubes (CNT), have been proposed for cathode application because of their good electrical conductivity, relatively high surface area, and high catalytic activity in ORR and OER. To facilitate those favorable characteristics of CNT, the development of a free-standing cathode could further enhance the performance of Li-O2 cells. In this work, the facile method for the preparation of CNT aerogels, via intensive homogenization and freeze-drying, is presented. The influence of the precursor concentration on the porous structure of obtained aerogels is analyzed. Furthermore, the correlation between concentration, porosity, and electrochemical performance is discussed.