Objective and Activities

The objective of the project is the preparation of innovative carbonaceous materials derived from woods to use as cathodes for oxygen-based electrochemical systems, such as fuel cells and metal-air batteries, in order to replace the highly expensive platinum-dispersed carbons (Pt/C), typically used as electrocatalysts for oxygen-based reactions.

To achieve this goal, the research project is structured into four main activities (work packages) which involve the preparation, characterization and testing of air cathodes made with wood-derived activated carbons.

Firstly, the research is involved in the selection of wooden materials with specific physico-chemical properties, so as to obtain highly porous activated carbons with good performances in terms of oxygen diffusion and electrical conductivity.

Hence, starting from literature studies, several woods are subjected to anatomical structural and chemical characterizations to select the species that are subsequently used for the carbon preparation.

Figure 1. Vine sawdust after washing with distilled water at 40°C

Figure 2. Vine sawdust after carbonization at 700° C

Then, the activity is centered on the identification of a suitable procedure for the production of carbons.

The woods will undergo one or more carbonization steps in order to convert the typical lignocellulosic structure of the wooden biomass into a graphitic structure.

Furthermore, the woods may also be subjected to some additional steps, such as washing, powdering and chemical treatments, for the removal of undesired impurities, the improvement of the biomass homogeneity, and eventually, the introduction of catalysts for the cathodic oxygen reactions.

After, the obtained carbons are characterized through thermal, optical and structural techniques with the purpose of estimating the graphitization degree, porosity and specific surface area, presence of structural defects and thermal stability, since these properties strongly affect the final performances of the air cathode in the cell.

Figure 3. SEM image of vine sawdust at a magnification of 630x

Figure 4. SEM image of an air-cathode derived from vine sawdust

Finally, the wood-derived carbons are used for the production of the air cathodes, which are subsequently analysed in cell configuration through electrochemical tests effected on aluminum-air batteries (Al-air) made with pure aluminum discs, biodegradable gel polymer electrolytes and the prepared wood-derived cathodes.