X. Jiang, F. Liu, C. Xiong
Wuhan Institute of Technology,
Keywords: one-spot synthesis, hierarchical structure, cathode, li-ion battery
Summary:The layered lithium-metal oxides are considered as one of the most promising cathode material for Li-ion batteries, However, their widespread applications are limited by their poor rate performance and cycle stability resulting from the Ni2+/ Li+ mixing which depresses the Li+ mobility. Herein, we developed a one-spot method using glucose as the blowing agent and urea as the chelation agent to prepare hierarchical porous nano-/microsphere LiNi0.5Mn0.2Co0.3O2 (NMC523). In the voltage range of 3.0-4.2, 3.0-4.5 and 3.0-4.8V, the specific gravimetric discharge capacities of NCM523 are 175.6, 244.2 and 217.4 mAh g-1.The material exhibits not only a relatively high discharge capacity but also relatively good rate performance and cycling stability in the range of 3.0-4.5V, the discharge capacity was kept at 130.3 mAh g-1 for 50 cycles. The enhancement of the material is attributed to the hierarchical porous nanostructure of NCM523, which could serve as shortcuts for the fast migration of electrolyte, Li+ and electrons, the polyhedrons with exposed active crystal facets that could provide more channels for Li+ diffusion. Moreover, as revealed by the XRD Rietveld refinement analysis, the negligible Ni2+/ Li+ mixing level and high crystallinity also resulted in the relatively excellent stability. The one-spot approach proposed in this work can be extended to fabricate NCM series as well as other mixed trasition metal-based material for Li-ion batteries.