Up‐Scaled Microspherical Aggregates of LiFe_0.4V_0.4PO₄/C Nanocomposites as Cathode Materials for High‐Rate Li‐Ion Batteries

Abstract

A series of microspherical LiFexV2/3−2x/3PO4/C (0<x<1) composites are successfully prepared using spray drying and the carbothermal reduction method. Compared with Li3V2(PO4)3/C and LiFePO4/C, LiFe0.4V0.4PO4/C is a solid solution and has a microspherical morphology. The LiFe0.4V0.4PO4/C microspheres with an essentially log‐normal distribution around 18.2 μm consist of nanosized LiFe0.4V0.4PO4/C particles as building blocks, which have an average size of around 50 nm, a specific surface area of 11.3 m2 g−1, and a Barrett–Joyner–Halenda pore diameter of 21.9 nm. Moreover, LiFe0.4V0.4PO4/C delivers a discharge capacity of 144.8 mAh g−1 at C/10, which is close to the theoretical discharge capacity of 148.2 mAh g−1 in the insertion/extraction process at 2.5–4.3 V. Even at 10C and 20C, LiFe0.4V0.4PO4/C shows excellent specific capacities of 125.2 and 119.6 mAh g−1, respectively, corresponding to excellent rate capacity retentions of close to 86.5 % and 82.6 %, respectively.

Spray-Drying of Electrode Materials for Lithium- and Sodium-Ion Batteries

“…Regarding the inorganic active material, heat treatment usually aims at a homogeneous, single-phase composition. Occasionally (see Composites at the end of Table 1), the precursor obtained by spray-drying of a solution is deliberately meant to crystallize into a mixture of two active phases, for example LiFePO 4 -Li 3 V 2 (PO 4 ) 3 [359,360,361,362,363]. …”