Quantitative Analysis of Energy and Power on Direct 

Methanol Fuel Cell Systems 

by Rongzhong Jiang and Deryn Chu 

ARL-TR-3458 April 2005 

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Army Research Laboratory 

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ARL-TR-3458 April 2005 

Quantitative Analysis of Energy and Power on Direct 

Methanol Fuel Cell Systems 

Rongzhong Jiang and Deryn Chu

Sensors and Electron Devices Directorate, ARL 

Approved for public release; distribution unlimited.
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Quantitative Analysis of Energy and Power on Direct Methanol Fuel Cell 

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Rongzhong Jiang and Deryn Chu 

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14. ABSTRACT 

Two commercial direct methanol fuel cell (DMFC) systems, designed with the same power (25W) but different sizes 

(size ratio in 11 to 1), were evaluated by constant current discharge at various current loadings and environmental 

temperatures. Quantitative analysis of fuel consumption and energy output was achieved by a simple mathematical 

treatment of the experimental data. The larger DMFC system gives higher energy density (770 Wh/Kg) than that of the 

smaller one (450 Wh/Kg) based on the fuel weight. The smaller DMFC system has higher power density (15.3 W/Kg) 

than that of the larger one (3.5 W/Kg) based on system weight. Heat dissipation is attributed to be the main problem of 

limiting the discharge performance for the smaller DMFC system. Too high and too low ambient temperature will 

cause the energy density to decrease for the DMFC systems. The desire ambient temperature for the present DMFC 

systems is 20-30 o

C. The length of operation time for the DMFC systems also affects the energy output. Minimum time 

(varying with experimental conditions) is needed for the DMFC system to reach a maximum power and energy output. 

15. SUBJECT TERMS DMFC, Fuel Cell, Fuel Cell System, Energy Analysis

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Rongzhong Jiang 

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iii 

Contents 

Introduction 1 

Experimental 1 

DMFC Systems .......................................................................................................................1

Instrumental and Procedures................................................................................................2

Results and Discussion 2 

Voltage-Current and Power-Current Curves......................................................................2

Long Term Discharge Behavior under Constant Current .................................................4

Quantitative Analysis of Energy and Power......................................................................10

Conclusion 20 

References 21

Distribution list 23 

Figures 

Figure 1A. Discharge voltage-current and power-current curves of SFC-A25 DMFC system 

at room temperature (19 ± 1 o

C). Cool condition: tested after start up. Warm condition: 

tested after 1.5A running for 4 hours. .....................................................................................................3 

Figure 1B. Discharge voltage-current and power-current curves of SFC-C25 DMFC system at 

different environmental temperatures. ....................................................................................................4 

Figure 2A. SFC-A25 DMFC performance under constant current discharge (2.0A) at room 

temperature (19 ± 1 o

C)...........................................................................................................................5 

Figure 2B. Discharge performance of SFC-C25 DMFC system under constant current (2.0A) 

discharge at room temperature (19 ± 1 o

C). ............................................................................................6 

Figure 3A. SFC-A25 DMFC performance at high current (4.0A) and room temperature (19 ± 

1 o

C). .......................................................................................................................................................7 

Figure 3B. Discharge performance of SFC-C25 DMFC system at high current (2.3A) and 

room temperature (19 ± 1 o

C). ................................................................................................................8
iv 

Figure 4. Discharge performance of SFC-C25 DMFC system under constant current (2.0A) 

discharge at high temperature (40 o

C).....................................................................................................9 

Figure 5A. Variations of energy density and power with time for SFC-A25 DMFC system 

under constant current discharge (2.0A)...............................................................................................12 

Figure 5B. Variation of discharge energy density and power with time for SFC-C25 DMFC 

system under constant current discharge (2.0A) at room temperature (19 ± 1 oC)...............................13 

Figure 6A. Effect of discharge current on energy density for SFC-A25 DMFC system under 

constant current discharge at room temperature (19 ± 1 o

C).................................................................14 

Figure 6B. Effect of discharge current on energy density for SFC-C25 DMFC system under 

constant current discharge at room temperature (19 ± 1 o

C).................................................................15 

Figure 7A. Effect of discharge current on power output for SFC-A25 DMFCl system under 

constant current discharge at room temperature (19 ± 1 o

C).................................................................16 

Figure 7B. Effect of discharge current on power output for SFC-C25 DMFC system at room 

temperature (19 ± 1 o

C).........................................................................................................................17 

Figure 8. Effect of environmental temperature on discharge energy density for SFC-C25 

DMFC system under constant current (2.0A) discharge.......................................................................18 

Figure 9. Effect of environmental temperature on discharge power for SFC-C25 fuel cell 

system under constant current (2.0A) discharge...................................................................................19

Tables 

Table 1. Summary of SFC-A25 DMFC system discharge performance at room temperature 

(19 ± 1 o

C)...............................................................................................................................................9 

Table 2. Summary of SFC-C25 DMFC system discharge performance at room temperature 

(19 ± 1 o

C)...............................................................................................................................................9 

Table 3. SFC-C25 discharge performance under constant current discharge (2.0A) at various 

environmental temperatures..................................................................................................................10 

Table 4. Effect of discharge current on fuel cartridge utilization at room temperature (19 ± 1 o

C). ........................................................................................................................................................13 

Table 5. Effect of environmental temperature on fuel cartridge utilization under constant 

current discharge (2.0A). ......................................................................................................................13 

Table 6. Summary of SFC-A25 DMFC system performance. ....................................................................19 

Table 7. Summary of SFC-C25 DMFC system Performance. ....................................................................20
1 

Introduction 

Portable electric power source plays increasingly important role in communication, 

portable computers, digital cameras and modern military applications in the 21st century. 

The available battery technology does not meet the power requirement for these 

applications. Fuel cell technology is pursued to solve the problem of the need for electric 

powers. The most promising alternative for battery is direct methanol fuel cell (DMFC) 

[1-14], which is a type of polymer electrolyte membrane fuel cells. The advantage of 

DMFC over a hydrogen fuel cell is the high theoretical energy density of methanol (6100 

Wh/Kg, base on pure methanol) and the ease of containerization and transportation of 

liquid fuel. In recent years, the research and development of DMFC has attracted much 

attention. A practical power source of fuel cells is usually composed of a number of 

single fuel cells. Such a combination of single fuel cells is called fuel cell stack, which 

provides higher voltage, current, or power than a single fuel cell. An integration of 

multiple parts into a power source, such as fuel cell stack, air pumps, fuel pumps, flow 

meters, heat dissipation fans, transformers, sensors, electric circuit, and start-up-batteries 

is called as fuel cell system, which can continuously provide electric power as long as 

fuel is supplied. Several DMFC systems have been demonstrated with different sizes, 

shapes, materials, and power ranges. Although these DMFC systems are examined when 

they are made, no report quantitatively analyzing the fuel consumption and energy output 

for a DMFC system exists. The present article is to compares the effect of design features 

(compact design and non-compact design) of DMFC system on energy and power output. 

Experimental 

DMFC Systems 

Two DMFC systems were purchased from Smart Fuel Cell AG. One is SFC-A25. The 

output power by design is 25W. The discharge voltage ranges from 11 to 14V, depending 

on the output power. The total system volume is 20.4 liter, which is a non-compact 

design. The fuel cartridge is 2.5 liter, using concentrated methanol as fuel. The air is 

supplied to the fuel cell by an air-pump. Another DMFC system is SFC-C25. The 

nominal power by design is 25W. The nominal discharge voltage is 11 V. The total 

system volume is 1.9 liter, which belongs to a compact design. The fuel cartridge is 125 

ml, using 75% methanol as fuel. The air is supplied to the fuel cell by an air-pump. The 

system volume ratio of the compact to the non-compact DMFC systems is 0.093, 

although the two systems have about the same power output by design. 
2 

Instrumental and Procedures 

A battery test station (model No. BT-2043, Arbin Instruments) was used for the 

electrochemical measurements. The ambient temperature was controlled with a Tenney 

Environment Chamber (model No. BTRC), which was programmed through a computer 

with Linktenn II Software. The energy density of the fuel cells was quantitatively 

determined by constant current discharge. The amount of total fuel consumed was 

measured by the weighing of the fuel cartridge before and after each discharge 

experiment. 

Results and Discussion 

Voltage-Current and Power-Current Curves 

The non-compact and compact DMFC systems were generally evaluated by measuring 

the voltage-current and power-current curves. Figure 1A shows discharge performance of 

a non-compact DMFC system (SFC-A25). The open circuit voltage of the system is 12V 

after starting up and 15V after warming up. The voltage-current curves were obtained by 

multiple consecutive small steps of current change starting from open circuit statues. 

With current going up the voltage goes down until reaching the lower limit of system 

voltage (10V). The voltage-current curve for the cool condition is relatively straight, 

which implies an Omic-controlled electrochemical behavior. The discharge voltage is 

significantly higher for the warm condition, and the maximum current can go to 5A 

before reaching the system voltage limit. The voltage-current curve of the warm 

condition is relatively bent down, which implies a mass transfer-controlled 

electrochemical process at the high discharge current range. The power-current current 

curves were obtained by calculation from the voltage-current curves. The maximum 

discharge power is 31W for the cool condition and 52W for the warm condition. We 

were unable to measure the effect of environmental temperature on the discharge 

performance of the non-compact DMFC system because that system’s volume was too 

large to be arranged in the environmental chamber. 

Figure 1B shows the discharge performance of a compact DMFC system (SFC-C25). The 

open circuit voltage deceases from 15V to 13V as environmental temperature increases 

from 0 to 40 o

C. Discharge performance is better the lower the temperature. The compact 

DMFC system’s reverse phenomenon of discharge performance compared to the noncompact system may be attributed to a room too small for sufficient heat dissipation. The 

maximum discharge power at different environmental temperatures can be found from 

the power-current curves in the Figure 1B, and they are relatively close with values 

between 32 – 36W. 
3 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0

Current (A)

Voltage (V)

0

10

20

30

40

50

60

Power (W)

Cool Condition

Warm Condition

Figure 1A. Discharge voltage-current and power-current curves of SFC-A25 DMFC system 

at room temperature (19 ± 1 o

C). Cool condition: tested after start up. Warm condition: 

tested after 1.5A running for 4 hours. 
4 

0

2

4

6

8

10

12

14

16

0.0 1.0 2.0 3.0 4.0

Current (A)

Voltage (V)

0

5

10

15

20

25

30

35

40

Power (W)

0 oC

18 oC

30 oC

40 oC

Figure 1B. Discharge voltage-current and power-current curves of SFC-C25 DMFC 

system at different environmental temperatures. 

Long Term Discharge Behavior under Constant Current 

A voltage-current curve describes only the short term behavior of a DMFC system. In 

general, the long term behavior of a DMFC system is different than the short term 

behavior due to system factor changes in heat dissipation and mass transfer. Constant 

current discharge is a convenient way to measure a long term discharge performance. 

Figure 2A shows voltage-time curve of the non-compact DMFC system under constant 

current discharge (2.0A). Because of periodical air purging in the DMFC system, the 

voltage-time curve is not smooth, but fluctuates with the same periodical term. The step 

of purging air is designed to freshen the air electrode and to increase the performance of 

the fuel cell. The fluctuation of the voltage-time curve does not affect analyzing the data 

of the DMFC system if these fluctuated data points are not considered in the data 

treatment. As shown in Figure 2A, the voltage slowly increases with time, and becomes 

constant for a few hours later (without considering the fluctuated points). The discharge 

voltage is 12V at the beginning, and finally reaches 13V. No voltage decrease was found 

for continuous operation of the DMFC system. 

Figure 2B shows voltage-time curve of the compact DMFC system under constant 

current discharge (2A). Voltage fluctuation is also seen in the figure due to purging air by 

the internal system design. Therefore, in the present article the fluctuated data points are 
5 

not considered. The average discharge voltage of the compact DMFC system is 12V, 

about 1V lower than that of the non-compact DMFC system. 

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

0 100 200 300 400 500 600 700

Time (min)

Voltage (V)

Figure 2A. SFC-A25 DMFC performance under constant current discharge 

(2.0A) at room temperature (19 ± 1 o

C). 
6 

0

2

4

6

8

10

12

14

16

18

0 10 20 30 40 50 60 70

Time (min)

Voltage (V)

Figure 2B. Discharge performance of SFC-C25 DMFC system under constant current 

(2.0A) discharge at room temperature (19 ± 1 o

C). 

Increasing discharge current causes production of more heat, and eventually results in 

heat dissipation problem. Figure 3A and 3B show voltage-time curves under high current 

discharge for the non-compact and compact DMFC systems. For the non-compact DMFC 

system, a maximum current of 4.0A can be applied. For the compact DMFC system, only 

2.3A maximum current can be used. Under high current discharge the DMFC systems 

can operate only less than 20 minutes and must then be turned off due to reaching the 

system temperature limits. Heat dissipation causing problems with the DMFC system is 

further confirmed by increasing the environmental temperature. Figure 4 shows voltagetime curves at high environmental temperature under constant current (2.0A) discharge. 

The maximum operation time under this condition is only 20 minutes. 

The effect of discharge current on the operation performance of non-compact and 

compact DMFC systems is summarized in Table 1 and Table 2, respectively. Increasing 

discharge current results in decreasing average voltage and increasing average power. 

The effect of environmental temperature on the performance of compact DMFC system is 

summarized in Table 3. The variation of environmental temperature seems not to cause 

significant changes to average voltage and average power. 
7 

0.0

4.0

8.0

12.0

16.0

20.0

0 5 10 15 20

Time (min)

Voltage (V)

Figure 3A. SFC-A25 DMFC performance at high current (4.0A) and room 

temperature (19 ± 1 o

C). 
8 

0

2

4

6

8

10

12

14

16

18

0 2 4 6 8 10 12

Time (min)

Voltage (V)

Figure 3B. Discharge performance of SFC-C25 DMFC system at high current (2.3A) 

and room temperature (19 ± 1 o

C). 
9 

0

2

4

6

8

10

12

14

16

18

20

0 5 10 15 20 25

Time (min)

Voltage (V)

Figure 4. Discharge performance of SFC-C25 DMFC system under constant current 

(2.0A) discharge at high temperature (40 o

C). 

Table 1. Summary of SFC-A25 DMFC system discharge performance at room temperature (19 ± 1 o

C). 

Current (A) 1.5 2.0 3.0 4.0 

Average Voltage (V) 14 13 11 10 

Average Power (W) 20 26 34 41 

Energy Density (Wh/Kg Fuel) 333 722 771 753 

Table 2. Summary of SFC-C25 DMFC system discharge performance at room temperature (19 ± 1 oC). 

Current (A) 1.5 2.0 2.3 

Average Voltage (V) 12.5 11.5 10.0 

Average Power (W) 18.8 23.0 23.0 

Energy Density (Wh/Kg Fuel) 404.2 456.5 190.8 
10 

Table 3. SFC-C25 discharge performance under constant current discharge (2.0A) at various environmental 

temperatures. 

Temperature. 

(

o

C) 

Average 

Voltage (V) 

Average 

Power (W) 

Energy Based on Fuel 

(Wh/Kg) 

0 11.0 22.0 228.6 

18 11.5 23.0 456.5 

30 11.0 22.0 496.7 

40 11.5 23.0 488.3 

Quantitative Analysis of Energy and Power 

Generally, quantitative analysis of commercial DMFC systems is difficult because of 

many unknown factors affecting complex system integration, such as stack configuration, 

cell numbers in a fuel cell stack, style of air supply, fuel concentration, heat dissipation, 

operation of startup battery, and internal consumption of energy. 

We quantitatively analyze two types of DMFC systems, emphasizing energy output and 

fuel consumption. 

The energy output can be quantitatively calculated from the data of the voltage – time 

curves shown in Figure 2A and 2B. Here, we describe a method of analyzing energy 

conversion in the DMFC system under constant current discharge. The output energy can 

be expressed by an equation, 

∫ =

t

v t dt i E

0

( ) 3600 (1)

Where, E (energy, Wh) is the output energy of the fuel cell system; i (Ampere, A) is the 

discharge current; t (Second, s) is the time of the discharge process. v (Voltage, V) is the 

stack voltage, and v(t) is a function of stack voltage versus time. 

According to electrochemical knowledge, the consumed amount of fuel is proportional to 

the discharge capacity if neglecting the factor of fuel crossover or considering that the 

lost fuel by crossover is equal for per unit of time. Under constant current discharge the 

consumed fuel amount is also proportional to the discharge time. Therefore, we have, 

W = Ct (2)

Where, W (g) is the amount of consumed fuel, and C (g⋅s

-1) is a constant. Therefore, the 

output energy density Ed (Wh⋅kg-1) can be expressed as, 
11 

∫ =

t

d v t dt

Ct

i E

0

( ) 3600

1000

(3)

The constant, C, in equation (3) can be obtained from the weight loss of fuel cartridge for 

a time period during discharge. The function, v(t), is known from the voltage-time 

curves. Therefore, the equation (3) can be solved, and we can quantitatively describe the 

energy density for all the discharge time. 

Figure 5A shows variations of energy density and discharge power with time for the noncompact DMFC system. The energy density increases sharply from zero at the beginning 

time, then continues to increase very slowly, eventually reaching a plateau after a long 

time period. This phenomenon implies that the energy or fuel efficiency is affected by the 

length of an operation time of the DMFC system. The power-current curve is almost a 

plateau in Figure 5A, with only a small increase over time. Periodical fluctuation of 

power is seen in the power-time curve because of purging air by the DMFC system. 

However, the energy-time curve is smooth and without fluctuation, which indicates that 

short time purging of air apparently does not affect the integration of energy. 

Figure 5B shows variations of energy density and discharge power over time for the 

compact DMFC system. The energy density and discharge power have similar variations 

to those in figure 5A. However, the compact DMFC system self stopped for only a short 

time running due to the fuel limitation. The percentage of fuel cartridge use is 

summarized in Table 4 and 5. The fuel is unable to be completely used in the fuel 

cartridge. The highest fuel cartridge use is only 30.5% at room temperature under 2.0A 

discharge. Increasing current density or increasing temperature will cause fuel cartridge 

use to decrease due to overheating of the DMFC system. 
12 

0

100

200

300

400

500

600

700

800

0 100 200 300 400 500 600 700

Time (min)

Energy (Wh/kg)

0

5

10

15

20

25

30

35

40

45

50

Power (W)

Energy (Wh/Kg)

Power (W)

Figure 5A. Variations of energy density and power with time for SFC-A25 DMFC system 

under constant current discharge (2.0A). 
13 

0

100

200

300

400

500

0 10 20 30 40 50 60 70

Time (min)

Energy (Wh/Kg)

0

10

20

30

40

50

Power (W)

Energy (Wh/Kg)

Power (W)

Figure 5B. Variation of discharge energy density and power with time for SFC-C25 DMFC 

system under constant current discharge (2.0A) at room temperature (19 ± 1 o

C). 

Table 4. Effect of discharge current on fuel cartridge utilization at room temperature (19 ± 1 o

C). 

Current (A) 1.5 2.0 2.3 

Time Lasted (min) 60.5 61.8 11.3 

Fuel Consumed (g) 46.9 51.9 22.7 

Fuel Cartridge Utilization (%) 27.6 30.5 13.4 

Table 5. Effect of environmental temperature on fuel cartridge utilization under constant current discharge 

(2.0A). 

Temperature o

C 0 18 30 40 

Time Lasted (min) 27 61.8 52.7 20.0 

Fuel Consumed (g) 44.3 51.9 38.9 29.2 

Fuel Cartridge Utilization (%) 26.1 30.5 22.9 17.2 
14 

Figure 6A shows the effect of discharge current on energy density for the non-compact 

DMFC system. All these energy-time curves eventually form flat plateaus. Increasing the 

discharge current from 1.5A to 3.0A the plateau of energy density jumps appreciably. 

The maximum energy density is about 770 Wh/kg (based on fuel) for current 3.0A. The 

average energy density under different current discharge for the non-compact DMFC 

system is listed in Table 1. 

Figure 6B shows the effect of discharge current on energy density for the compact DMFC 

system. Increasing discharge current from 1.5A to 2.3A increases the energy density. 

However, the maximum energy density is limited to only about 450 Wh/kg for current 

2.0A. The poor performance of 2.3A discharge is attributed to system overheat. The 

average energy density under different current discharge for the compact DMFC system 

is listed in Table 2. 

0

100

200

300

400

500

600

700

800

900

0 50 100 150 200

Time (min)

Energy (Wh/kg)

3.0A 2.0A 1.5A

Figure 6A. Effect of discharge current on energy density for SFC-A25 DMFC system 

under constant current discharge at room temperature (19 ± 1 o

C). 
15 

0

100

200

300

400

500

0 10 20 30 40 50 60 70

Time (min)

Energy (Wh/Kg)

2.0A 1.5A 2.3A

Figure 6B. Effect of discharge current on energy density for SFC-C25 DMFC system 

under constant current discharge at room temperature (19 ± 1 o

C). 

Figures 7A and 7B show effect of discharge current on power output for the non-compact 

and compact DMFC systems respectively. These power-current curves form flat plateaus 

if not considering the experimental points by purging air. If discharge current is the same, 

the results of power output are relatively close by comparing the non-compact and 

compact DMFC systems. The non-compact DMFC system has higher discharge power 

because it can go to higher discharge current without causing a thermal problem. 
16 

0

5

10

15

20

25

30

35

40

0 50 100 150 200

Time (min)

Power (W)

3.0A 2.0A 1.5A

Figure 7A. Effect of discharge current on power output for SFC-A25 DMFCl system 

under constant current discharge at room temperature (19 ± 1 o

C). 
17 

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70

Time (min)

Power (W)

2.0A 2.3A 1.5A

Figure 7B. Effect of discharge current on power output for SFC-C25 DMFC system at 

room temperature (19 ± 1 o

C). 

Figure 8 shows effect of environmental temperature on discharge energy density for the 

compact DMFC system. The highest discharge energy density is obtained at 30 o

C. 

Increasing or deceasing temperature will cause energy density to decrease, and result in a 

self stopping of the DMFC system in a short operation time. The reason for the energy 

density drop is heat loss and lower electrochemical kinetics of the DMFC system in low 

temperature. Figure 9 shows the power output at various temperatures for the compact 

DMFC system. The power output variation is not appreciable (22 – 23 W) at different 

temperatures. Table 3 summarizes energy density and power output for the compact 

DMFC system at different temperatures. The overall discharge performance and 

electrochemical data for the non-compact and compact DMFC systems are summarized 

in Table 6 and Table 7 respectively. 
18 

0

100

200

300

400

500

600

0 10 20 30 40 50 60

Time (min)

Energy (Wh/Kg)

 30 oC

40 oC

18 oC

 0 oC

Figure 8. Effect of environmental temperature on discharge energy density for SFC-C25 

DMFC system under constant current (2.0A) discharge. 
19 

0

10

20

30

0 10 20 30 40 50 60

Time (min)

Power (W)

0 oC 18 oC 30 oC 40 oC

Figure 9. Effect of environmental temperature on discharge power for SFC-C25 fuel cell 

system under constant current (2.0A) discharge. 

Table 6. Summary of SFC-A25 DMFC system performance. 

System Weight + Fuel Cartridge (Kg) 9.7 

Fuel Cartridge Weight (Kg) 2.2 

Fuel Cartridge Volume (dm3) 2.5 

System Size (dm3) 20.4 

Average Voltage (V) (at 3A discharge) 11 

Average Power (W)* 34 

System Power Density (W/Kg)* 3.5 

System Power Density (W/L)* 1.7 

Energy Based on Fuel (Wh/Kg)* 771 

Energy Based on Fuel Cartridge (Wh/Kg)* 701 

Time needed for 1 cartridge to be full discharged at 3A (Hour) 46 

Energy Based on SFC-A25 System and Fuel Cartridge (Wh/Kg)* 159 for 1 cartridge used 

* Calculated with the data at 3A discharge. 
20 

Table 7. Summary of SFC-C25 DMFC system Performance. 

System Weight (Kg) 1.5 

Fuel Cartridge Weight (g) 170 

System Size (cm3) 1939.2 (19.4 x 12.25 x 8.16) 

Average Voltage (V) 11.5 

Average Power (W) 23 

System Power Density (W/Kg) 15.3 

System Power Density (W/L) 11.9 

Energy Base on Fuel (Wh/Kg) 450 

Energy Based on Fuel Cartridge (Wh/Kg)* 159 

Energy Based on SFC-C25 System and Fuel Cartridge 

(Wh/Kg)** 

16 (for 1 cartridge used) 

* About 60g methanol can be utilized for one fuel cartridge. 

** The total weight of system and fuel cartridge is 1.67Kg. 

Conclusion 

Quantitative analysis of energy density and fuel consumption for DMFC systems can be 

achieved under constant current discharge with a sample mathematical treatment of 

experimental data. By comparing two DMFC systems with non-compact and compact 

designs, the non-compact system has better heat dissipation and higher energy density 

based on fuel weight. The compact system has higher power density based on system 

weight. 
21 

References 

1. S. Surampudi, S. R. Narayanan, E. Vamos, H. Frank, G. Halpert, A. Laconti, J. 

Kosek, G. K. S. Prakash, and G. A. Olah, J. Power Sources, 47, 377 (1994). 

“Advances in direct oxidation methanol Fuel cells.” 

2. X. M. Ren, M. S. Wilson, and S. Gottesfeld, J. Electrochem. Soc., 143, L12 (1996). 

“High performance direct methanol polymer electrolyte fuel cells.” 

3. Q. B. Fan, C. Pu and E. S. Smotkin, J. Electrochem. Soc., 143, 3053 (1996). “Ins situ 

Fourier transform infrared-diffuse reflection spectroscopy of direct methanol fuel cell 

anodes and cathodes.” 

4. D. Chu and S. Gilman, J. Electrochem. Soc., 143, 1685 (1996). “Methanol electrooxidation on unsupported Pt-Ru alloys at different temperatures.” 

5. J. T. Wang, J. S. Wainright, R. F. Savinell and M. Litt, J. Applied Electrochem., 26, 

751 (1996). “A direct methanol fuel cell using acid-doped polybenzimidazole as 

polymer electrolyte.” 

6. C. K. Witham, W. Chun, T. I. Valdez, S. R. Narayanan, Electrochemical and Solid 

State Letters, 3, 497 (2000). “Performance of direct methanol fuel cell with sputterdeposited anode catalyst layers.” 

7. X. M. Ren, P. Zelenay, S. Thomas, J. Davey and S. Gottesfeld, J. Power Sources, 86, 

111 (2000). “Recent advances in direct methanol fuel cells at Los Alamos National 

Laboratory.” 

8. A. S. Arico, S. Srinvasan and A. Antonucci, Fuel cells, 1, 133 (2001). “DMFCs: 

From Fundamental Aspects to Technology Development.” 

9. D. Chu and S. Gilman, J. Electrochem. Soc., 141, 1770 (1994). “The Influence Of 

Methanol On O2 Electroreduction At A Rotating Pt Disk Electrode In Acid 

Electrolyte.” 

10. R. Jiang and D. Chu, J. Electrochem. Soc., 147, 4605 (2000). “Remarkably active 

catalysts for the electroreduction of O2 to H2O for use in an acidic electrolyte 

containing concentrated methanol.” 

11. X. M. Ren, T. E. Springer, T. A. Zawodzinski and S. Gottesfeld, J. Electrochem. 

Soc., 147, 466 (2000). “Mthanol transports through Nafion membranes, electroosmotic drag effects on potential step measurements.” 
22 

12. Rongzhong Jiang and Deryn Chu, Electrochem. Solid-State Lett., 5 (7), A156-A159 

(2002). “CO2 Crossover through A Nafion Membrane in A Direct Methanol Fuel 

Cell.” 

13. Rongzhong Jiang, Charles Rong and Deryn Chu, Journal of Power Sources, 126, 

119-124, (2004). “Determination of energy efficiency for a direct methanol fuel cell 

stack by a method of fuel circulation.” 

14. Rongzhong Jiang and Deryn Chu, Journal of the Electrochemical Society, 151, A69-

A76, (2004). “Comparative Studies of Methanol Crossover and Cell Performance for 

a Direct Methanol Fuel Cell.” 
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