Sol-gel-assisted, fast and low-temperature synthesis of La-doped Li3V2(PO4)(3)/C cathode materials for lithium-ion batteries

摘要

A series of La-doped Li3V2(PO4)(3)/C cathode materials for Li-ion batteries are synthesized by a sol-gel-assisted, low-temperature sintering process. La(NO3)(3) acts not only as the La source, but also, together with the intermediate product LiNO3, promotes combustion, the ultrahigh exothermic energy that is advantageous for the nucleation process. The subsequent sintering process at 600 degrees C for 4 h is sufficient to produce highly crystalline La-doped Li3V2(PO4)(3)/C composites. The as-prepared cathode materials display smaller particle size, lower electron-transfer resistance and faster Li ion migration, which is ascribed to enhanced Li-ion transfer because of the La doping. The resulting Li3V1.96La0.04(PO4)(3)/C cathode has a stable specific capacity of 160 mA h g(-1) at low charge-discharge rates over 100 cycles, and retained a stable capacity of up to 116 mA h g(-1) at a rate of 5 C, which is 40% higher than the undoped pristine cathode.