On the Mechanism of the Electrochemical Reaction of Tin Phosphide with Lithium

Abstract
With a view to the possible application of tin phosphide (Sn4P3)(Sn4P3) as the negative electrode in advanced lithium-ion battery test cells, Li7Li7 and P31P31 magic angle spinning nuclear magnetic resonance and Sn119Sn119 Mössbauer spectroscopy techniques were used to reveal the mechanism of the electrochemical reactions in lithium test cells. The formation of LiPLi3PLiPLi3P and Sn through a conversion reaction was observed. This process was followed by the successive formation of Li–SnLi–Sn intermetallics up to Li4.4SnLi4.4Sn stoichiometry. Reversibility was restricted to the formation of lithium–tin intermetallics thus limiting the maximum allowed reversible capacity.