Synthesis of spherical LiFePO₄ microparticles with encapsulated carbon nanotubes for high-power lithium-ion batteries

Abstract

Lithium ferrophosphate – LiFePO₄(LFP) – is one of the widely studied and used materials for lithium-ion batteries. However, one of the main drawbacks of LFP is its poor electrical conductivity. To address this issue, we propose an effective approach based on encapsulating carbon nanotubes within the volume of LFP particles in the volume of spherical LFP particles. Electrodes based on the obtained materials exhibit more aTₜᵣactive electrochemical characteristics than LFP obtained by the standard method: increased specific capacity (62 and 92 mAh g–1 at a current density of 20C for LFP and LFP/SWCNT, respectively), stability of cyclic characteristics (preservation of 98% capacity after 100 charge/discharge cycles for LFP/SWCNT and 96.5% for LFP), as well as reduced charge transfer resistance. Encapsulation of SWCNT into the structure of iron phosphate during deposition is an easy-to-implement approach to formation modified LFP-based cathodes with improved characteristics, which expands the possibilities of their practical application in high-power lithium-ion batteries.