Printed supercapacitors based on graphene and other carbon materials show promise for energy storage applications. Supercapacitors provide higher power density than batteries and longer lifespan than electrolytic capacitors. Graphene is a promising material for supercapacitors due to its large surface area, high conductivity, short ion diffusion path, and ability to be manufactured at scale. Methods for producing graphene-based supercapacitors include direct laser writing, lithography, and direct printing of graphene inks. These graphene microsupercapacitors show energy densities comparable to lithium-ion batteries with orders of magnitude higher power density. Further cost reductions could enable broader adoption of printed supercapacitors for portable devices, electric vehicles, and stationary energy storage.

1. Printed Supercapacitors
Based on Graphene
and Other Carbon Materials
Bing Hsieh

2. 我想生命的意義不光是在解決各種問題，而是在
發揚人性光輝，縱使這種想法可能只是一種慰籍。

3. Energy Storage Market Space
Portable Devices; Motive Energy Storage; Stationary Storage.
Power
Tools
Home/
Buildings
Storage
SC companies:
Maxwell,
Nichicon,
AVX,
Murata,
Cornell Dubilier
Vishay
Yunasko (2010)
SC startups:
CAP-XX
Paper Battery Co.
NanoTune (2007)

4. Ragone Plots of energy generation
devices

5. CAPACITOR TECHNOLOGY COMPARISON
1.0 MJ (277 Wh) Energy Delivery System
Capacitor Type Mass (kg) Volume (m3) Cost (k$) Response time (s)
Electrostatic 200,000 140 700 10
-9
Electrolytic 10,000 2.2 300 10
-4
Electrochemical
Electric Double Layer Capacitor
(EDLC); Supercapacitor (SC)
30- 100 .02- 0.1 2 - 20 ~1
Features & Benefits
•Up to 1,000,000 duty cycles or 10 year DC life*
•Highest power and energy
•Up to 18 kW/kg of Specific Power
•Up to 4.00 Wh of Stored Energy; Maxwell 2.85 w DuraBlue cell
•7.7 Wh/kg ¼ of that of Lead acid 0.5kg, 13.8 cm x 6 cm
•Threaded terminals or laser-weldable posts

6. Summary of Supercapacitor Device Characteristics
Device
V
rated
C
(F)
R
(mOhm)
(3)
RC
sec
Wh/kg
(1)
W/kg
(95%)
(2)
W/kg
Match.
Imped.
Wgt.
(kg)
Vol.
lit.
Maxwell
Technol.
2.7 605 0.90 0.55 2.35 1139 9597 0.20 0.211
Vinatech 2.7 336 3.5 1.2 4.5 1085 9656 0.054 0.057
Ioxus 2.7 2000 0.54 1.1 4.0 923 8210 0.37 0.346
Skeleton
Technol.
3.4 3200 0.475 1.52 9.0 1730 15400 0.40 0.284
Yunasko 2.75 1275 0.11 0.13 4.55 8791 78125 0.22 0.15
Yunasko* 2.7 5200 1.5 7.8 30 3395 30200 0.068 0.038
Nesscap 2.7 3160 0.4 1.3 4.4 982 8728 0.522 0.379
LS Cable 2.8 3200 0.25 0.80 3.7 1400 12400 0.63 0.47
BatScap 2.7 2680 0.20 0.54 4.2 2050 18225 0.50 0.572
JSR-Micro* 3.8 1100 1.15 1.21 10 2450 21880 0.144 0.077
(1) Energy density at 400 W/kg constant power, Vrated - 1/2 Vrated
(2) Power based on P=9/16*(1-EF)*V2/R, EF=efficiency of discharge
(3) Steady-state resistance including pore resistance
* Hybrid "Li-ion capacitors"

7. Huge Market Size for Energy Storage Devices
2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Portable Energy Storage
Lux Research 27.0
Markets& Markets 10.9
Motive Energy Storage
IMS Research 30.0 31.0 33.0 38.0 42.0 47.0
Lux Research 21.0
Stationary Energy Storage
Lux Research 2.8
Total Battery Market
Battery University 47.5 74.0
Freedonia 121.0 132.0
Lux Research 50.8
Lithium Batteris
Statista 1.5 10.0 15.6
Navigant Research 5.7 24.0
Frost & Sullivan 11.7 22.5 33.1
Lithium battieries in Evs
Frost & Sullivan 0.4 7.6
Supercapacitors in Transporation
Paumanok Publications 0.4
Next Gen Batteries
Navigant Research 0.2 9.4
All in Billions of US dollars

8. LIB in Full Throttle but SCs are Making
a Strong Inroad into the EV Market
• Replacement of lithium-ion traction
batteries with SCs in hybrid electric
vehicles is now commonplace but the
opposite is not, despite their low
energy density.
• Maxwell Technologies sold over
600K units of 3000F supercap modules
for start-stop application in hybrids.
• Trains, planes, and automobiles
account for about 40% of today’s
400M global supercap market.

9. Energy Storage in Portable Devices
Current Trends:
1. Thinner devices with reduced battery capacity.
2. Modern devices become more power hungry.
3. Including a supercap enables a more efficient use of
energy.
4. Supercaps as back-up power for memory protection.
Recent Market Announcement:
CAP-XX: 1mm thick surface mount supercap for
smartphones that use re-flow solder board and high-
power camera flashes.
Paper Battery: 0.3mm thick supercap enables extended
battery energy by up to 33%
2013 Value Sales

10. Cost is almost everything?
•Cost is the key market consideration
and barrier for mass adaptation.
•Materials and assembly account
for 40% and 60% of production cost.
•Material cost includes:
electrode cost(50%); packaging (25%)
electrolyte (15%); separator (10%)

11. Supercap: a Strong Contender for
Stationary Energy Storage
At 200 Wh/kg, A 150 L (4.5 ft3=
= 21” cube storage will be
needed.
At 100 Wh/kg, A 300 L (26”
cube) storage will be needed
•Supercaps have replaced 3% of LIB market with only 1% of LIB energy
density because of their long cycle life.
•Market research company IDTechEx recently presented a brave thesis
that “Supercapacitors can destroy the lithium-ion battery market“
Function
Graphene Supercapacitor Lithium-ion (general)
Charge time 1–10 seconds 10–60 minutes
Cycle life >1 million 1000
Cell voltage 2.3 to 2.75V 3.6 to 3.7V
Specific energy (Wh/kg) 180 (lab research) 200
Specific power (W/kg) 10,000+ 2,000
Cost per Wh
$120
$20 (research)
$0.50-$1.00 (large system)
Service life >15 years
5 years (depending upon
rating levels, i.e. 80% of
capacity)
Charge temperature –40 to 65°C (–40 to 149°F) 0 to 45°C (32°to 113°F)
Costs & Environmental
Hazards of Disposal or
Replacement
LOW HIGH

12. Stationary Energy Storage Road Map
$400/kWh
2015:
•Cost for a 100kWh storage system =
$400/kWh x 100kWh=$40000
•if the life to the system is 2000 cycles
which is 5.4yr
•if a house uses 80kWh/day, the total
energy need over 5.4yr is 157,000kWh
•$40000/157000kWh = ȼ25/kWh
2030:
•Cost for a 100kWh storage system =
$100/kWh x 100kWh=$10000
•if the life to the system is 3500 cycles
which is 10yr
•if a house uses 80kWh/day, the total
energy need over 10yr is 292,000kWh
•$10000/292000kWh = ȼ3.0/kWh
$100/kWh
2015 2030
Supercapacitors could realize ȼ3/kWh mark in 2020 – 2025.

13. Next Gen Storage Technologies:
the hunt for the ultimate energy storage technology
• Lithium Metal Batteries with Solid Electrolytes
• Lithium Sulfur
• Metal Air
• Non-Li Batteries (Na, Mg)
• Flow Batteries
• Supercapacitors
- Established Technologies
- Safe without reactive metals
- Environmentally friendly
- Low cost materials
- Long cycle life
- High power density
- 10 – 25X lower energy density than Li ion batteries.

14. Large Gains in Supercapacitor Research Last Year
Research last year!

15. What is a Supercapacitor (SC)?
Electrochemical Double Layer Capacitor (EDLC)
1/CT = 1/CA + 1/CB
When CA = CB = C
CT = C/2
𝐸 =
1
4
𝐶𝑉2 =
𝟏
𝟒
(εrε0A/L)V2
P = V2/4R =
𝑉2
4
𝐴
ρ𝐿
Both High energy and Power density requires
(1) High voltage electrolyte materials,
(2) Large electrode surface,
(3) Short Ion diffusion length
High Power density requires
(4) Low resistance electrode material

16. A Typical sandwich-SC (SSC) Cell Assembly
Positive Pole
Negative Pole
Separator
Carbon Electrode
Current Collector
Carbon Electrode
Safety Vent
Sealing Disk
Aluminum Can

17. Types of Eletrolytes
• Aqueous electrolytes: PVA/H2SO4/H2O (small voltage window of 1.3V)
• Organic electrolytes: N+(Et)4
.BF4
-/CH3CN (large voltage window of 2.5V)
• Ionic Liquids: High voltage window of >4.5V
• Solid state electrolytes

18. Sandwich SC vs In-plan MSC
C ∝ 𝑊 𝑒/𝑊𝑠
C ∝ 𝑡2
t 𝑠 = 20 – 30 µm; t1 = 20-200 µm
C ∝ 𝑡1
𝑡1↑, ion diffusion length ↑,
Charging rate ↓, P ↓

19. Graphene
discovered in 2004
1 µm2 area contains about
19 million fused benzene rings!
0.34 nm
3.4 Å
Al was discovered in 1820 and find its killer app in 1920
What would the kill app for graphene be?

20. Why Graphene materials for SCs Applications?
Materials
Specific
Surface
Area (m2/g)
Density
(g/cm3)
Conductivity
(S/cm)
Capacitance
(Aqueous
Electrolyte)
Capacitance
(Organic
Electrolyte
F/g F/cm3 F/g F/cm3
Activated Carbon 1000-3500 0.4-0.7 0.1-1 150-300 <80 100-200 <50
Activated Carbon Fibers 1000-3000 0.3-0.8 5-10 120-370 <150 80-200 <120
Carbon Aerogels 400-1000 0.5-0.7 1-10 100-125 <80 <80 <40
Carbide derived Carbon 1000-3000 180 150
Onion Like Carbon 600 30
Graphite 10 2.26 104 - - - -
Carbon Nanotube 120-1000 0.6 104-105 50-200 <60 100 <30
Graphene 2630 1.2 106 100-200 >100 80-110 >80
Graphene meets the following requirement for High energy and power densities:
(1) large electrode surface,
(2) high capacitance;
(3) Low resistance,
(4) Short Ion diffusion path for superior frequency
Response and rate capability (in-plane ion transport)

21. Graphene Sandwich vs. In-plan MSC
SubstrateSubstrate- - -
+ + +
_
_
_
_
_
+
_
_
_
_+
_
-
+
+
+ + + - - -

22. Rapidly Up-Trending in SCs and Graphene
$3.5B in 2020
SC market to show
3-4X increase in 5 yrs
Graphene market to show
4-5X increase in 5 yrs

23. Manufacturing Methods of Graphene
GrapheneQuality&Cost
Scalability
Chemical Structure of
Graphene Oxide (GO)
(an insulator).
Greaphene based materials have
become “THE” material Platform
for a wide range of applications

24. Fabrication Methods of Patterned Graphene Layers
1. Coat graphene oxide layer followed by etching.
2. Print with graphene inks
3. Print with graphene oxide inks followed by reduction.
4. Direct laser scribe on polyimide or other common polymers

25. Graphene SC and MSC via Direct Laser Writing –
The UCLA approach
•LS line resolution is ~20 µm.
•Graphene oxide layer (3 µm, 10-3 S/cm)
expanded to 7.6 µm (7K layers) after laser
exposure. High conductivity of 2350 S/cm
•No current collector used in both SSC and
MSC.

26. Microsupercapcitors via Lithography –
The Max-Planck-Institute for Polymer Research
Only 15 nm thick
15 graphene Layers
200 um

27. Ragone Plots of graphene SSCs vs MSCs
• Although LSG is 500X thicker than MPG, the LSG-MSC and the MPG-MSC show similar performance
characteristics, indicating superior performance for the MPG-MSC. This could be due to the use of Au
current collector, and increased ion transport with the absence of GO interspatial layer in the MPG-MSC.
• GO is relatively unstable as compare to graphene and may gives substantial leakage current.
• The energy density of these graphene MSCs are similar to the commercial thin film lithium ion batteries
while maintaining 4 orders of magnitude higher in power density.
Substrate
LSG LSG LSG
330 µm
150 µm
Substrate
AuAuAu
200 µm 200 µm 200 µm70 µm 70 µm
7.6 µm
15 nm
3 µm
Graphene oxide
UCLA – LightScribed GO Max Plank – Mathane Plasma reduced GO

28. Direct Printing: from MSC to Large SC
Direct printing of graphene oxide inks onto a substrate followed by radiation.
Direct printing methods: inkjet, Gravure, flexo, waterless offset, screen printing, or
Microcontact, followed by optional printing of current collectors
Direct printing should be superior than direct laser writing:
(1) A high throughput manufacturing process which could enable large SC at low cost.
(2) Enhanced stability, reduced leakage current, improved ion transport due to the
avoidance of graphene oxide interspatial layer.
Inkjet printed graphene oxide Inkjet printed graphene Gravuer graphene
Thin Plastic Substrate
Graphene
AgAgAg
Graphene Graphene
Thin Plastic Substrate
Graphene Graphene Graphene

29. Coat an electrolyte
Print Silver current collector
Reduce GO to graphene
GO
Flexible Substrate
Print GO
A Proposed Process & the Resulting Printed GSC
(A)
(B)
(C)
(D)
(E)

30. • GO synthesis via a modified Hummers route established. GO concentration up to
6.0g/L was prepared.
• We casted GO films of various thickness (1 – 10 µm) on PET.
Free Standing, highly flexible graphene oxide papers (20-60 µm)
have been prepared by suction filtration. These GO papers can be
used to prepare higher concentration GO inks.
• High power 980nm laser (50W) obliterated GO films; while
LightScribe laser (780 nm, 47mW) failed to reduce our GO films.
• 266nm laser effectively reduced GO film.
1cm2 areas written with the 266nm laser.
Resistivity of 100, 20, and 10k Ω respectively
404nm
455nm
266nm
Initial Results

31. A Sandwich SC with High Specific Energy
Hydrogen Annealed
graphene (HAG)
Graphene based sandwich SC maybe ready for stationary storage application!
HAG+binder+conducting
additive on nickel mesh

32. In-Plane SC with High Energy Density
Activated carbon based in-plane SC exceeds LIB in energy density!?
Activated carbon in-plane SC performs better than that based on Graphene?!

33. Vertically Oriented Graphene
RF Plasma Enhanced CVD (JME, inc)
1. Vertically aligned graphene works well in both sandwich and in-plane (planar) device.
2. Ion channels in alignment with electric field to give enhanced capacity and charging rate.
3. No distributed charge storage behavior due to low ionic resistance, lower RC time constant.
4. Frequency independent impedance behavior suitable for voltage filtering application for
portable electronics.
5. too expansive?
50nm

35. Mission Statement
Develop, manufacture, and market high
energy density supercapacitors and establish
them as the main stream energy storage
devices for mobile devices, EVs, as well as for
energy harvested from renewable resources.

36. Concluding Remarks
• A couple years ago Tesla CEO Elon Musk said in an
offhand remark that he thought super capacitors
— rather than batteries — might be the energy
storage tech to deliver an important
breakthrough for electric transportation.
• According to a recent article in the Economist,
supercapacitors are already starting to be used in
a variety of novel ways in electric vehicles