Synthesis of MgCo2O4-coated Li4Ti5O12 composite anodes using co-precipitation method for lithium-ion batteries

Abstract

In the present work, we report synthesis of MgCo2O4 (MCO)/Li4Ti5O12 (LTO) composites for Li-ion battery anodes by a co-precipitation method. The objective of this work is to replace expensive Co with Mg and also to exploit advantages of both MCO and LTO. Three samples of MCO/LTO particles with different MCO proportion have various average particle sizes of 38.1, 56.9, and 58.5 nm, confirmed by scanning electron microscopy. Electrochemical studies show that a MCO/LTO anode offers a discharge capacity of ca. 300 mAh g−1, which is two times higher than that achieved by pristine LTO. The MCO/LTO anode also retains 75% of its initial capacity, even if the discharge rate is increased to 5 C. Cyclic stability test reveals that the composite anode still maintains nearly 85.5% of its initial capacity after 150 cycles. Electrochemical impedance spectroscopy indicates that the equivalent series resistance of MCO/LTO electrodes is significantly lower than that of LTO, i.e., from 35.5 to 9.9 Ω. The enhanced performance of the composite electrodes can be attributed to its improved conductivity as well as to the surface modification of LTO particles by MCO nanoparticle deposition which leads to increased number of active sites on the former.