Yiyang Liu – Seminar/Ph.D. Thesis Defense – Wednesday, October 18, 2017 at 2:00 P.M.

JSNN – Yiyang Liu – Ph.D. Thesis Defense/Wednesday Seminar

Candidate: Yiyang Liu

Advisor and Committee Chair: Jianjun Wei, Ph.D.

Department: Nanoscience

Date: Wednesday, October 18, 2017

Time: 2:00 P.M. – 4:00 P.M.

Location: JSNN 209 Open Room

2907 E. Gate City Blvd., Greensboro, NC 27401

Title: “Manganese Dioxide Based Nano-Architectures And Supercapacitor Materials in Energy Storage Applications.”


This study describes the growth mechanism, magneto-capacitance enhancement and non-separator design of α-MnO2 on super-aligned electrospun carbon nanofibers (SA-ECNFs). The morphology of the SA-ECNFs/MnO2 hybrid electrodes were investigated by scanning electron microscope (SEM). The elemental/crystal information was characterized by X-ray photoelectron spectroscopy (XPS), Energy-dispersive X-ray spectroscopy (EDX) and X-Ray Diffraction Spectroscopy (XRD). The energy storage performance was tested by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charging/discharging technique. A time-dependent growth analysis suggests a three-step kinetics mechanism for the electrodeposition of MnOon SA-ECNFs with high specific capacitance. Furthermore, modified deposition setting can synthesize electrodes with mT magneto-supercapacitance enhancement ability. The three-step kinetics mechanism also suggests an ultra-thick MnOcoating practical for non-separator configuration. The hps/hsep model shows its potential to assemble a cell without the use of a separator, which is novel for energy storage applications.