Olivine-based blended compounds as positive electrodes for lithium batteries

Abstract

Blended cathode materials made by mixing LiFePO4 (LFP) with LiMnPO4 (LMP) or LiNi1/3Mn1/3Co1/3O2 (NMC) that exhibit either high specific energy and high rate capability were investigated. The layered blend LMP-LFP and the physically mixed blend NMC-LFP are evaluated in terms of particle morphology and electrochemical performance. Results indicate that the LMP-LFP (66:33) blend has a better discharge rate than the LiMn1-yFeyPO4 with the same composition (y = 0.33), and NMC-LFP (70:30) delivers a remarkable stable capacity over 125 cycles. Finally, in situ voltage measurement methods were applied for the evaluation of the phase evolution of blended cathodes and gradual changes in cell behavior upon cycling. We also discuss through these examples the promising development of blends as future electrodes for new generations of Li-ion batteries.