La2(MoO4)3@C as novel anode for lithium ion battery: Structural and chemical evolutions upon electrochemical cycling

Abstract

La2(MoO4)3 is a kind of transition metal molybdate. It has been proved to be a possible anode material for lithium ion batteries due to the high theoretical capacity. In this work, molybdenum-based La2(MoO4)3 material is successfully synthesized through a traditional solid-state reaction method. Carbon-coated La2(MoO4)3 is designed by using glucose as carbon source. By comparing the carbon-coated La2(MoO4)3 with the carbon-free La2(MoO4)3, carbon-coated La2(MoO4)3 delivers better cyclic stability and rate performance. Carbon-coated La2(MoO4)3 obtains a reversible charge capacity of 525.9 mA h g−1 at 100 mA g−1 after 100 cycles, corresponding to capacity retention of 75.2%. However, the capacity retention of carbon-free La2(MoO4)3 is only 33.4%. The results indicate that carbon layer can evidently alleviate the irreversibility of structure and improve capacity retention of La2(MoO4)3. It demonstrates that the carbon-coated La2(MoO4)3 composite can be a possible anode candidate for high capacity lithium ion batteries. In addition, in-situ X-ray diffraction investigation (XRD), ex-situ X-ray photoelectron spectroscopy (XPS), and ex-situ transmission electron microscopy (TEM) are employed to analyze the electrochemical behavior during process of cycling. These experimental results indicate that the conversion behavior of La2(MoO4)3 upon lithiation/delithiation is a process of structural pulverization. Based on that, our work provides guidance for the research of molybdenum-based electrode materials.