Synergetic effects of LiNi1/3Co1/3Mn1/3O2-LiMn2O4 blended materials on lithium ionic transport for power performance

Blended cathode materials generally suffer from capacity loss impacting on their power performance in lithium-ion batteries. This work reports a systematic study of LiNi1/3Co1/3Mn1/3O2-LiMn2O4 blended materials incorporated with characterizations of particles, calculations of charging-discharging characters, and analysis of cyclic voltammetry. A synergetic effect, a capacity increasing at high discharging rate referring to the linear superposition of blending components, is observed in a wide blending ratio for blended materials. The model analysis of charging-discharging characters shows that LiMn2O4 releases more reversible capacity in the blended materials than when it is alone at the same electrochemical condition. An equivalent circuit model is proposed to interpret the electrochemical behaviors showed in electrochemical impedance spectroscopy. The mechanism of particle synergetic effect is attributed to the compensating property of blending components, which improves the inter-particles diffusibility of Li+, therefore reduces the particle impedance of blended materials promoting rate performance. Over the blending range, the scheme LiNi1/3Co1/3Mn1/3O2/LiMn2O4-Blend (50:50 in mass ratio) shows the best performance and highest capacity increasing.