Flexible Nanocellulose paper based electronics
Xiaodan Zhang
March 14th, 2014
School of Materials Science & Engineering
Georgia Institute of Technology
1
Introduction
Paper based electronics
Microfibrillated cellulose (MFC)
Paper based electronics
Abundant
Low cost
Flexible
Green
MFC for electronics :
excellent mechanical,
optical(transparent) properties, etc.
Recyclable
2
I. Siro, D. Plackett, Cellulose, 17 (2010) 459-494.
Introduction
Paper based electronics
Multi-walled carbon nanotubes
(MWCNT)/paper based supercapacitors (1)
Flexible and transparent paper-based ionic diode (2)
3
Cellulose aerogel based supercapacitors(3)
Paper-based solar cells (4)
(1) Zhang, et al., Journal of Materials Chemistry A, 2013, 1(19), 5835-5839.
(2) Zhang, el, Journal of Power Sources, 2014, 246, 283-289.
(3) Zhang, et al., Journal of Physical Chemistry C, 2012, 116 (16), 9227-9234.
(4) Cha, et al. Energy & Environmental Science, 2012,5, 6071-6075.
Background
Fabrication of MFC/MWCNTs based supercapacitors
Electric double layer structure
Structure and mechanism of supercapacitors. 1 and 2—current collectors; 3 and 4—
electrodes; 5—separator; 6—electrolyte; 7—pores in the electrode material; 8—
positive charge; 9—negative ion; 10—negative charge(electrons); 11—positive ion.
4
V.V.N. Obreja, Physica E-Low-Dimensional Systems & Nanostructures, 40 (2008) 2596-2605.
Experiment
Design
Fabrication of MFC/MWCNTs based supercapacitors
 Experiment Design
 Electrode sheets: MWCNT, MFC, PEO/LiCl (solid polyelectrolyte).
 Separator sheets: MFC, PEO/LiCl (solid polyelectrolyte).
5
Design of MFC/MWCNTs based supercapacitors. PEO is impregnated into both
electrodes and separator but not demonstrated here.
Results
Fabrication of MFC/MWCNTs based supercapacitors
SEM images of a) electrode sheets of MWCNT as active electrode materials, PEO and
LiCl as electrolyte, MFC as sheet supporter. Solid arrows point to the representative
entangled MWCNT, dashed arrows point to the representative MFC fibers. b)
separator sheets with PEO and LiCl as electrolyte, MFC as film supporter.
6
Results
Fabrication of MFC/MWCNTs based supercapacitors
a) Cyclic voltammetry(CV) of MWCNT/MFC supercapacitors at different scan rates. b)
Galvanostate charge-discharge curve at different current densities.
∫ IdV
CS =
s × ∆V × r
CS ∞ area, r-1
7
Cs =
2I
s × dV
dt
CS ∞ slope-1
Cs: specific areal capacitance, I :current density, V: voltage, s : area of electrodes, r: scan rate,
∆V: voltage scan range.
Results
Fabrication of MFC/MWCNTs based supercapacitors
(a)
(b)
309mF/cm2
Bad!
a) Cyclic voltammetry of MWCNT/MFC supercapacitors at different thickness at a scan rate of
20mV/s. b) Specific areal capacitance and specific mass capacitance with different thickness of
electrode sheets at scan rate of 20mV/s.
CS ∞ area, r-1
8
Results
(a)
Fabrication of MFC/MWCNTs based supercapacitors
(b)
a) CV plots of supercapacitors at different bending radius(area of supercapacitance being
6mm*8mm). b) Photo of flexibility of the supercapacitors.
Bending will not influence the electrochemical properties of the
MFC/MWCNT supercapapcitors
9
Results
Fabrication of MFC/MWCNTs based supercapacitors
Stress-strain curve of MWCNT/MFC electrode sheet
The mechanical properties of electrode sheets are much better than the liquid
based supercapacitors.
10
Summary
Fabrication of MFC/MWCNTs based supercapacitors
 MFC/MWCNTs based supercapacitors were fabricated with
specific capacitance was calculated to be 309 mF/cm2 at
20mV/s from cyclic voltammetry.
 The electrochemical properties of the supercapacitors will
not be affected under different bending radius.
 The mechanical properties of MFC/MWCNTs based
supercapacitors are excellent.
11
Acknowledgement
 Thesis advisors:
Dr.Yulin Deng, CHBE
Dr.Youjiang Wang, MSE
 Group members
 Institute of Paper Science and Technology fellowship
12
13
Introduction
Paper based electronics
Multi-walled carbon nanotubes
(MWCNT)/paper based supercapacitors (1)
Flexible and transparent paper-based ionic diode (2)
14
Cellulose aerogel based supercapacitors(3)
Paper-based solar cells (4)
(1) Zhang, et al., Journal of Materials Chemistry A, 2013, 1(19), 5835-5839.
(2) Zhang, el, Journal of Power Sources, 2014, 246, 283-289.
(3) Zhang, et al., Journal of Physical Chemistry C, 2012, 116 (16), 9227-9234.
(4) Cha, et al. Energy & Environmental Science, 2012,5, 6071-6075.

Medical Fee Structure

projected schedule of graduate classes

TRABAJOS FIN DE MASTER (Curso 2013-2014) Alumno