2015 Volume 83 Issue 4 Pages 249-255
Highly-dispersed Li3V1.8Al0.2(PO4)3 nanoparticles which are directly impregnated onto the surface of multi-walled carbon nanotubes (MWCNT) were successfully synthesized via a unique two-step process using an ultracentrifugation at 75,000 g. The synthetic procedure of the Li3V1.8Al0.2(PO4)3/MWCNT composite involves the following two steps: i) precipitation of V1.8Al0.2O3 (10–100 nm) nanoparticles on the surface of MWCNT, and ii) the subsequent transformation of the V1.8Al0.2O3 into the Li3V1.8Al0.2(PO4)3 nanoparticles without any change of their shape and dimensions. The 10% of Al-doping brought out an increase in the discharge capacity from 119 to 124 mAh g−1 per Li3V2−xAlx(PO4)3, which corresponds to a 14% increase of the Li3V2−xAlx(PO4)3 utilization ratio. The Al-doping also reduced its electric resistance by 26%. The Li3V1.8Al0.2(PO4)3/MWCNT with such an efficient electron transport can deliver excellent electrochemical performances ever attained to date; capacity density of 85 mA h g−1 at a high discharge rate of 480C and stable cycle performance over 10,000 cycles at 10C rate with 85% retention of the initial capacity.
