Rational design of Sn_(4)P_(3)/Ti_(3)C_(2)Tx composite anode with enhanced performance for potassium-ion battery

摘要

The potential application of high-capacity Sn_(4)P_(3)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 conduc-tivity.To address the above issues,sandwich-like struc-tured Sn_(4)P_(3)/Ti_(3)C_(2)T_(x)was designed and synthesized as anode material for PIBs.As a result,Sn_(4)P_(3)/Ti_(3)C_(2)T_(x)pre-sents 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 perfor-mance of sandwich-like structured Sn_(4)P_(3)/Ti_(3)C_(2)Tx is orig-inated from the synergistic effect between Sn_(4)P_(3)and Ti_(3)C_(2)T_(x),where Ti_(3)C_(2)T_(x)acts as a conductive matrix to facilitate electron transfer and buffer the volume change of Sn_(4)P_(3)particles upon cycling,while Sn_(4)P_(3)serves as pillars to prevent the collapse and stacking of Ti_(3)C_(2)T_(x)sheets.Moreover,significant capacitive contribution is demonstrated as a major contributor to the excellent rate capability.