Facile Synthesis of MoO3 Nanobelts with Carbon Dispersed Structure and Its Application As Anode of Lithium Ion Batteries
Authors: Xia Qing , Zhao Hailei , Du Zhihong , Gao Chunhui , Zeng Zhipeng , Zhang Zijia , Zhang Tianhou 
Published: February 2020

Lithium ion batteries (LIBs) have been successfully regarded as excellent power sources for energy conversion and storage technology, due to their high energy density, long lifespan, no memory and environmental benignity [1]. Transition metal oxides have been regarded as promising candidates for anode materials of LIBs due to their high theoretical capacity [
2
]. Molybdenum oxides (MoO3 or MoO2) have attracted enormous interest in recent decades, owing to their high thermal chemical stabilities and high theoretical capacity (e.g. 1117 mAh g-1 for MoO3 and 838 mAh g-1 for MoO2) [
3
]. In this paper, we design and fabricate a carbon dispersed structured α-MoO3 nanobelts by a facile hydrothermal method. The addition of activated carbon is in an attempt to address the poor conductivity and also prevent the aggregation of the α-MoO3, consequently improve the rate capability and cycling stability of α-MoO3 anode materials.

The prepared MoO3/C nanobelts are systematically characterized by XRD, FTIR, TGA, SEM, TEM, and EDS techniques, and the electrochemical performance is investigated by CV and constant current discharge-charge test techniques.

XRD analysis reveals that the as-synthesized material is α-MoO3. The addition of activated carbon has no influence on the crystal structure of α-MoO3. The peak positions of MoO3/C are as same as the pure MoO3, indicating that the existence of carbon does not affect the lattice structure of MoO3. FTIR analysis confirms the presence of carbon in the composite. The carbon content in MoO3/C composite was determined to be about 7.85% on the basis of the TGA analysis. The MoO3 and MoO3/C samples are investigated as anode materials for LIBs. When tested at a current density of 100 mA g-1 between 0.01-3.0 V, the MoO3/C anode exhibits a much better cycling performance than the MoO3 anode, delivering a higher discharge capacity of ~1000 mAh g-1 after 50 cycles. In contrast, the capacity of pure MoO3 decreased continuously with the increasing number of cycles, only remains 632 mAh g-1 after 50 cycles. The improved cycling performance of MoO3/C can be attributed to the presence of activated carbon, which improves electronic conductivity. Moreover, the activated carbon prevents MoO3 nanobelts agglomeration and acts as a sponge for relieving the large volume change during cycling, thus further enhance the structural stability.

In summary, α-MoO3 nanobelts with carbon dispersed structure can be fabricated through a one-pot hydrothermal method. When evaluated as anode materials for LIBs, the MoO3/C exhibit exceptional high specific capacity and outstanding rate capability The results suggested this kind of composite could become a promising candidate for anode materials of high-performance lithium ion batteries.

References

[1] Zhou X, Wan L J, Guo Y G. Advanced Materials, 2013, 25(15): 2152-2157.

[2] Armand M, Tarascon J M. Nature, 2008, 451(7179): 652-657.

[3] W. Wen and J. Wu, Appl. Mater. Interfaces (2011) 4112.