The role of porosity-graded electrode in mitigating performance degradation of high voltage lithium-ion battery

LiNi0.5Mn1.5O4 (LNMO) is one of the high potential cathodes for lithium-ion batteries due to the high operating voltage (4.7 V vs. Li) and high specific energy (650Wh.kg(-1)). However, severe accelerated performance degradations occurring especially at the interface between electrode and electrolyte, hinder the implementation of the LNMO. In this work, porosity-graded electrodes are designed to mitigate LNMO degradation. The LNMO was synthetized via solid-state reaction. X-ray powder diffraction (XRD) and scanning electron microscope (SEM) were utilized in this study. The increase in porosity can improve the conductivity and diffusivity of lithium-ions through the electrode. In addition, solid electrolyte interphase (SEI) formation can be varied and controlled when the porosity is different inside the electrode. The test results showed, comparing with conventional single-layer electrode, the double-layer porosity-graded LNMO cathode reduced the capacity fade about 8.285% for full cell and 5.29% for half-cell, respectively.