Tin Phosphide as a Promising Anode Material for Na‐Ion Batteries

Sn4P3 is introduced for the first time as an anode material for Na-ion batteries. Sn4P3 delivers a high reversible capacity of 718 mA h g−1, and shows very stable cycle performance with negligible capa­city fading over 100 cycles, which is attributed to the confinement effect of Sn nanocrystallites in the amorphous phosphorus matrix during cycling.