Multi-cations doped LiVPO4F cathode for lithium-ion batteries

The multi-cations doped LiVPO 4 F , nominally Li 0.97 Cr 0.01 V 0.95 Al 0.01 Nb 0.02 PO 4 F 0.97 , is prepared by Chromium ( Cr ) doping on lithium site and Al – Nb co-doping on vanadium site via a conventional carbothermal reduction (CTR) route. The crystallographic lattice volume, particle size and morphology are not obviously changed comparing with un-doped LiVPO 4 F . However, the high rate and lifetime cycling performances are noticeably improved although the capacities at very low currents are slightly decreased. The reversible capacity at 1/10 C, 1 C, 2 C and 4 C of the pristine LiVPO 4 F is 143 mA h g -1 , 99 mA h g -1 , 86 mA h g -1 and 70 mA h g -1 , respectively, while that of the doped counterpart is 138 mA h g -1 , 102 mA h g -1 , 95 mA h g -1 and 82 mA h g -1 , respectively. The capacity retention after 100 galvanostatic cycles at 1.5 C is enhanced from 85.4% to 90.9% by such multi-cations doping. Moreover, the initial coulombic efficiency is significantly increased from 81.8% to 90.3% as well.