Rational design of Sn₄P₃/Ti₃C₂T _x composite anode with enhanced performance for potassium-ion battery

The potential application of high-capacity Sn₄P₃ anode for potassium-ion batteries (PIBs) is hindered by the poor cycle stability mainly rooted from the huge volume changes upon cycling and low electronic conductivity. To address the above issues, sandwich-like structured Sn₄P₃/Ti₃C₂T_x was designed and synthesized as anode material for PIBs. As a result, Sn₄P₃/Ti₃C₂T_x presents superior cycle stability (retains a capacity of 103.2 mAh·g⁻¹ even after 300 cycles at 1000 mA·g⁻¹) and rate capability (delivers 60.7 mAh·g⁻¹ at high current density of 2000 mA·g⁻¹). The excellent electrochemical performance of sandwich-like structured Sn₄P₃/Ti₃C₂T_x is originated from the synergistic effect between Sn₄P₃ and Ti₃C₂T_x, where Ti₃C₂T_x acts as a conductive matrix to facilitate electron transfer and buffer the volume change of Sn₄P₃ particles upon cycling, while Sn₄P₃ serves as pillars to prevent the collapse and stacking of Ti₃C₂T_x sheets. Moreover, significant capacitive contribution is demonstrated as a major contributor to the excellent rate capability. Graphical abstract: [Figure not available: see fulltext.]