Enhancing lithium-ion and electric conductive Li_(2)FeSiO_(4)cathode through in situ boron-doping and carbon-coating strategy

摘要

The extremely low electrical conductivity and ion-diffusion coefficient of Li_(2)FeSiO_(4)limits its application as a cathode material in lithium-ion batteries.Therefore,in situ boron-doped Li_(2)FeSi_(1)-xB_(x)O_(4-δ)/C(x=0,0.01,0.03,0.05 and 0.07)at the Si site was prepared via the solid-state reaction method using pitch as the c arbon source.B doping in the lattice structure and a c arbon coating on the surface of the composites could effectively enhance the Li^(+)/electron conductivity.Moreover,the reduced particle size of the active material with the relatively high specific area via borondoped modification could improve the wettability between the electrolyte and cathode.With the synergistic effect of appropriate boron doping and carbon coating,it exhibits a good rate performance,specific capacity,and cycling performance.As a result,the as-prepared Li_(2)FeSi_(0.95)B_(0.05)O_(4-δ)/C cathode showed a high discharge capacity of 160.7mAh·g^(-1)at 0.2C,and the capacity retention rate was 96%after 100 cycles at 1.0C.This work presents an effective path for designing advanced cathode materials for lithium-ion batteries.