High Performance, Stoichiometric ZnSnP₂ Anode for Rechargeable Lithium‐Ion Battery with Concomitant Conversion from Chalcopyrite to Sphalerite Phase

Abstract Herein, we report chalcopyrite phase of zinc tin phosphide (ZnSnP₂) as an anode for high rate, rechargeable, lithium‐ion battery. In‐situ Raman spectroscopy reveals the conversion of chalcopyrite phase of ZnSnP₂ to a symmetric sphalerite phase upon cycling, which helps in achieving stable and reversible capacity at high discharge rates. This is due to the low bandgap and high conductivity of the sphalerite phase. The in‐situ phase conversion is extremely important as it is difficult to synthesize bulk ZnSnP₂ sphalerite phase by the known methods till date. After full phase conversion, a reversible capacity of 750 mAh g⁻¹ is obtained towards the end of 1700 cycles at a rate of 5 A g⁻¹. Full cell assembled using LiCoO₂ as the cathode material yields a stable performance with a discharge capacity of around 500 mAh g⁻¹ at 0.5 A g⁻¹ and the rate capability studies demonstrate reversible capacities up to 15 A g⁻¹ current.