Student News

Envisioning Sustainable Futures Competition

The 6th Annual 2014 Sustainability Project Competition was held on Wednesday, April 16, 2014 at 2:00 pm in the Gordon Library.

Congratulations to the winners of the Graduate section:

Fabrication of TiO2/Graphene in Core Shell Structure as Advanced Anode Materials

Yinjie Cen, Yuqin Yao, Quan Xu, Zhenhai Xia

Advisors:  Richard Sisson, Jianyu Liang

Graduate Student: Yinjie Cen is being questioned in picture on the right.

Abstract

TiO2 nanoparticles (NPs) synthesized by a facile sol-gel method were encapsulated in graphene nanosheets (GNS) to enhance their performance as the active anode material in Li-ion batteries. The encapsulation was facilitated by electrostatic interaction between the positively charged, silane decorated, TiO2 surface and the negatively charged graphene oxide. Following encapsulation, the graphene oxide was reduced to create a graphene encapsulated TiO2 nanocomposite. Scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM) imaging revealed the uniform and individual wrapping of the TiO2 NPs by graphene. X-ray powder diffraction (XRD) results further validated uniform distribution of graphene encapsulated anatase TiO2 NPs. Fourier Transformation Infrared Spectroscopy (FTIR) and Zeta potential results confirmed that the electrostatic interaction was effective in facilitating the uniform wrapping of graphene oxide around TiO2 NPs. Electrochemical performance of the nanocomposite was tested by cyclic voltammetry, and coin cell tests. The graphene encapsulated TiO2 materials demonstrated a high initial capacity of 409mAh·g-1 at 1C, while retaining a capacity of 141mAh·g-1 at 20C. The nanocomposite electrode also showed a Coulombic efficiency above 98% and good long term cycling performance, as high as 343mAh·g-1 after 100 cycles, at a rate of 1C. Possible mechanisms resulting in the observed improved performance are discussed in this report.

For more information regarding the Sustainability Project Competition -

http://www.wpi.edu/about/sustainability.html

                    

                          Sponsored by the President’s Task Force on Sustainability

                            and Environmental and Sustainability Studies Program

                 

April 16, 2014