Electrochemical Na-insertion/extraction properties of Sn-P anodes

Thick-film electrodes of tin phosphides, Sn4P3 and SnP3, were prepared using a mechanical alloying method followed by a gas-deposition method, and were evaluated as Na-ion battery anodes in an organic electrolyte and ionic liquid electrolytes. The Sn4P3 electrode showed a better cycling performance in the organic electrolyte compared with the SnP3 electrode and an Sn electrode. The performance of the Sn4P3 electrode was further improved by using ionic liquid electrolytes because of a uniformly formed surface layer and resulting uniform sodiation/desodiation reactions on the electrode.