Phosphorus modification of Li-rich and Mn-based Li_1.2[Co_0.13Ni_0.13Mn_0.54]O₂ cathode material for lithium-ion battery

Abstract

The enhanced electrochemical performance of the lithium-rich solid solution Li_1.2[Co_0.13Ni_0.13Mn_0.54]O₂ (LMNCO) cathode was enhanced by phosphorus incorporation. The various phosphorus contents were introduced by adding NH₄H₂PO₄ into the raw materials. The pristine sample and the sulfur incorporated samples were characterized by X-ray diffraction(XRD), high resolution transmission electron microscopy(HRTEM), electrochemical impedance spectroscopy(EIS). Electrochemical performance was assessed by measuring parameters such as charge and discharge capacity, rate capability in lithium ion cells. The results show that the LMNCOP-03 material has the best initial discharge capacity of 280 mAh·g^-1. Moreover, it has about 212.2 mAh·g^-1 and 170.6 mAh·g^-1 at 1.0 C and 3.0 C rate, respectively. The LMNCOP-03 material shows an improved rate performance attributed to the enhanced electrical conductivity and lithium ion diffusion, which is proved by EIS tests.