Algae Derived Electrodes for Rechargeable Na-Ion Batteries: Materials Characterization and Electrochemical Performances

The use of algal biomasses as alternative materials to the fossil fuel-derived ones for the production of non-graphitic hard carbon open structures (HC) as active materials for Na-ion batteries electrodes is considered. Selected algae are dried and decomposed in tubular furnaces under inert nitrogen atmosphere at temperatures comprised between 700 and 1000°C. The products, before and after decomposition, are characterized with optical and SEM microscopes and with XRD analysis. This organic hard carbon is tested as electrode's active material of a sodium half coin cell. Different cyclic discharge/charge profiles between 2.5 and 0.01V are performed, the electrochemical performances of the cell analyzed and compared to those of identically assembled cells, with the only difference in the use of synthetic hard carbon instead of algae derived one. The performances of the two kinds of cells are comparable.