Chemical Engineering Journal, Vol.372, 408-419, 2019
Metal-organic framework-mediated synthesis of LiNi0.5Mn1.5O4: Tuning the Mn3+ content and electrochemical performance by organic ligands
Spinel LiNi0.5Mn1.5O4 has drawn considerable attention due to its wide working voltage, high energy density, low cost, natural abundance, and environmental friendliness. However, as an electrode in lithium-ion batteries, its inferior ionic/electronic conductivity and high Mn3+ concentration at the surface lead to low specific capacitance and poor rate/cycling performance, which have impeded its applications. In this work, a series of LiNi0.5Mn1.5O4 is synthesized via a hydrothermally assisted method coupled with a high-temperature calcination process based on metal-organic frameworks. In addition, this study systematically explores the effect of the organic ligand species on the electrochemical properties of synthesized LiNi0.5Mn1.5O4. Furthermore, an optimal LiNi0.5Mn1.5O4 electrode is demonstrated with a high discharge capacity of 145.3 mA h g(-1) at a 1C rate. It provides a large capacity of 122.6 mA h g(-1) even at a discharge rate as high as 20C. In particular, at an elevated temperature, 94.4% of the capacity is retained after 500 cycles at 1C and 40 degrees C. Thus, LiNi0.5Mn1.5O4 will be a promising cathode for applications in next-generation lithium-ion batteries with high energy densities.
Keywords:Metal-organic framework;Spinel LiNi0.5Mn1.5O4 cathode material;Lithium-ion battery;High energy density;Hydrothermal method