Electrode Engineering of Conversion-based Negative Electrodes for Na-ion Batteries.

Due to lower costs and higher abundance of sodium, Na-ion battery technology can offer a good alternative to Li-ion batteries. Much research is focusing on developing new cathode and anode materials but the importance of the electrode engineering on the electrochemical performance is often neglected. The electrode composition is especially crucial for conversion reaction-based materials where the composite electrode (active material, conducting additive and binder) has to buffer the huge volume change occurring upon cycling.

Better cycling performances of bulk Sb in Na-ion batteries compared to Li-ion systems: an unexpected electrochemical mechanism.

Pure micrometric antimony can be successfully used as negative electrode material in Na-ion batteries, sustaining a capacity close to 600 mAh g(-1) at a high rate with a Coulombic efficiency of 99 over 160 cycles, an extremely high capacity compared to any other compound tested against both Li and Na. The reaction mechanism with Na does not simply go through the alloying mechanism observed for Li where the intermediate species are those expected from the phase diagram. In the case of Na, the intermediate phases are mostly amorphous and could not be precisely identified.