Boosting the kinetics of PF_(6)^(-) into graphitic layers for the optimal cathode of dual-ion batteries:The rehearsal of pre-intercalating Li^(+)

摘要

Large anions exhibit slow diffusion kinetics in graphite cathode of dual-ion batteries(DIBs);particularly at high current density,it suffers severely from the largely-reduced interlayer utilization of graphite cathode,which as a bottleneck limits the fast charge application of DIBs.To maximize interlayer utilization and achieve faster anion diffusion kinetics,a fast and uncrowded anion transport channel must be established.Herein,Li^(+)was pre-intercalated into the graphite paper(GP)cathode to increase the interlayer spacing,and then hosted for the PF_(6)^(-)anion storage.Combined with theoretical calculation,it shows that the local interlayer spacing enlargement and the residual Li^(+)reduce the anion intercalation energy and diffusion barrier,leading to better rate stability.The obtained GP with Li^(+)pre-intercalation(GP-Li)electrode exhibits a discharge capacity of 23.1 m Ah g^(-1) at a high current of 1300 m A g^(-1).This work provides a facile method to efficiently improve the interlayer utilization of graphite cathode at large currents.