LiNi_0.7Mn_0.3O₂ as a Cheap Cobalt Free Nickel Rich Cathode Material for High-Performance Li-Ion Batteries

Abstract

A high-quality Lithium Nickel Manganese Oxide (LiNi0.7Mn0.3O2) material is successfully synthesized via co-precipitation. The precursors for lithium rechargeable batteries have been prepared using starting materials (NiCl2.6H2O and MnSO4.H2O) with precipitating agents of oxalic acid and sodium hydroxide, Ethylene diamine tetra acetic (EDTA) and sodium hydroxide, and sodium carbonate for oxalate co-precipitation, hydroxide co-precipitation, and carbonate co-precipitation, respectively. Then, the precursors were calcined at 500°C for 5 hours, mixed with Li2CO3, and sintered at 850°C for 15 hours under oxygen. X-ray Diffraction (XRD) analysis results show that the particles obtained by oxalate co-precipitation (LiNi0.7Mn0.3O2-C2O4) have higher crystallinity and more uniform particle shape than hydroxide co-precipitation and carbonate co-precipitation. The Fourier Transform Infrared (FTIR) spectroscopy characterization shows no carbonate group peak in the LiNi0.7Mn0.3O2-C2O4. Furthermore, electrochemical tests were analyzed by evaluating the charge/discharge curves and cycling performance. The highest specific discharge capacity of 122 mAh/g was achieved by the LiNi0.7Mn0.3O2-C2O4 sample, which also had a low capacity loss (22.7%), retaining 89.9% of its initial specific capacity at 0.5C between 2.5 and 4.25 V after 45 cycles. Based on these results, a cheap cobalt-free cathode material is promising for a new commercialized Li-ion battery.