Measurements of fracture properties of MWCNTs modified LiNi_0.5Mn_0.3Co_0.2O₂ electrodes by a modified shear lag model

The multi-walled carbon nanotubes (MWCNTs) modified LiNi_0.5Mn_0.3Co_0.2O₂ (NMC532) electrodes were prepared by using blade-coated method. The corresponding microstructure morphology were observed by scanning microscopy electron. The impedance spectroscopy and cycle performances of the electrodes with different MWCNTs contents were measured and discussed. Tensile fracture measurements of the electrodes were performed with the aid of digital image correlation technique. The cracking nucleation and propagation on the active layer surface were in situ monitored. A modified shear lag model was developed to analyze the fracture strength, fracture energy and fracture toughness of the active layer during tensions. The effect of MWCNTs on tensile failure mechanisms of two-layered NMC532 electrodes was discussed. The proposed method is useful for appraising the mechanical properties of other advanced active layers in lithium ion batteries.