1. Introduction
The world needs more energy to meet socio-economic development requirements and enhance global living standards to continue to improve (BP, 2019;
IPCC, 2012). In 2018, the global energy demand rose by 2.3%, the fastest in the last decade (IEA, 2019). By 2040 it is forecasted that various sources of energy will increase and still be widely used including the non- renewables such as coal, gas, and oil (BP, 2019). Around 1.1 billion people (14% of the global population) have no access to electricity (IEA, 2017). Many of those without access are found in rural areas, and more than 95% of those living without electricity are in countries in developing Asia and sub-Saharan Africa (ibid). To date, several communities still found on off-grid and don't have access to electricity (ibid) to light their homes or power, even small devices. In the Philippines, an estimated off-
grid demand of 209.86 MW in 2015 was recorded (ADB, 2018). The need for energy to even light the homes of the isolated communities are too basic but many don't have access. Efforts to address off-grid communities are through the use of solar panels, one of the easier to install or use.
In 2015, the solar-powered electricity has reached around 227 GWe, about 1% of all energy used globally (WEC, nd). However, one of the disadvantages of solar energy is the availability of the sunlight requiring the user to have energy storage to be of use when sunlight is
unavailable (Green Match, 2019; Renewable Resources Co, 2016). For ordinary families in many far-flung and off-grid communities, lighting their homes during evenings is a necessity. Most of these communities use kerosene (or other similar) lamps and candles. Candles and kerosene lamps (gasera) are among the most common cause Abstract: The paper presents the design, testing, and construction of a new energy source derived from the ionized solution and electrodes. The design focused on the optimal salt- liquid mixture as an electrolyte and the type of electrodes used to produce better energy output. Included the design is the number of cells and the packaging set-up of the power source device. It tested different liquids as electrolyte, including tap water, rainwater, cooking oil, and human urine with NaCl as well as Coca Cola and Vinegar. Results showed that the energy produced from different liquid-salt ratio and the size of the electrodes used varied slightly. With the consideration of the device functionality, manageability, total cost, and general appearance, a ten-cell zinc-cupper electrolytic cell battery using salt-water- electrolyte produced 7.5 volts for 17 hours which can be
extended by replacing electrolyte. The prototype device can light an LED lamp or charge a mobile phone.
Keywords: redox reaction, emergency power-source, small energy charging device, salt- liquid electrolyte performance, zinc-copper electrodes, saltwater lamp
Design, Testing, and Construction of an Alternative Zn-Cu Electrolytic Cell Battery
Felipe B. Café III1, Jacob M. Cioco1, Leslie R. Conge1, Adrian U. Gadin, Nikko Ardel P.
Floretes, Walvies Mc L. Alcos
1Students, College of Engineering, Samar State University, Philippines
of fires in households (PSA, 2018; BFP, 2015). In 2017, the Philippines listed a total of 463 cases of fire attributed to candles and gasera, about 40% lower than 2016 (PSA, 2018).
Aside from the risk of fire, higher cost of usage and illumination quality, candles and gasera’s (which burns kerosene for light) are also not environmentally clean.
This potential risk was also one of the reasons why many lamps have been created using alternative sources of energy to provide illumination to homes. In 2010, a lantern powered a metal-air battery using salt-water as an electrolyte catches the attention of many. Today the said
technology is available in the market with an energy output of 5volts and 160mA current capable of lighting eight ultra-bright LEDs (SALt, 2018). A metal-air battery
electrochemical cell uses an anode made from metal and an external cathode of ambient air usually with an aqueous or aprotic electrolyte (Georgi, nd; 2006). The metal-air battery described by SALt (2018) uses the salt-water mixture as its electrolyte to facilitate the flow of electrons from the metal anode and an air cathode.
The archipelagic condition of the Philippines provides far-flung, isolated communities with vast resources (saltwater) as the electrolyte of a metal-air battery. The use of seawater is a cheaper alternative to photovoltaic cells and another alternative power source (Rao, Hoge, Zakrzewski, Shah and Hamlen, 2013). On the other hand, salt (among others) are valuable resources in far- flung upland communities. If such resource will be used for energy production, it may compete with the flavoring of the food. This raises the question of using other types of liquid-salt mixture to serve as the
electrolyte. Also, the question of whether the existing electrolytic battery power can be
enhanced to improve voltage output to increase its utility was explored in this project.
2. Objectives
The paper presents the design, testing, and construction of a novel energy source from an ionized solution and metal, specifically, it will;
2.1 Assess the output voltage and current from different liquid-salt ratio using the following liquids;
a. tap water and salt, b. cooking oil and salt, c. rainwater and salt, d. urine and salt, e. vinegar, and f. soda
2.2 Determine the output voltage and current considering the dimensions of copper and zinc electrodes,
2.3 Determine the output volume and current considering fuel-cell design and connectivity,
2.4 Design and construct device enclosure, and
2.5 Assess the acceptability of the developed device considering cost- effectiveness and utility.
3. Methodology 3.1. Research Design
The developed project was based on an experimental study of what liquid-salt mixture, size of copper and zinc and the fuel cell design produced the needed output power to light a LED lamp and charge a device like a cellular phone. The battery was developed using electrolytic cell technology.
A total of 26 set-ups and more than 130 experimental trials were conducted. The optimal design of mixture and set-up was
used in developing the enclosure of the device which was evaluated for its
acceptability using likert scale for utility and a cost-benefit analysis was also conducted.
3.2. Testing and Evaluation
Electrolyte Design Mixture. The alternative battery used the electrolytic cell technology (Peshin, 2018; Bertrand, nd. ) wherein instead of using a salt bridge used a salt-liquid mixture to maintain the neutrality of water surrounding the electrodes. There are a total of six types of liquid used in two liquid-salt proportion. One set used 350 ml of liquid and 4 tablespoons of salt while the other set used 100 ml of liquid and 5
tablespoon of salt for tap water, cooking oil, rainwater, and urine. On the other hand, vinegar and soda (Coca-Cola) was not mixed with any salt as these are already ionized liquids. With the use of a digital multimeter tester, the output voltage and current were measured. The testing was done at least three times from three different set-ups.
Figure 1: Liquid-salt electrolyte performance experimentation
Electrodes Size and Energy
Produced. The size of electrodes used was tested; one using 100 x 33mm or 100 x 67
mm copper and zincs. A total of five pairs of copper and zinc were examined. The said electrodes were immersed in a 350 ml to 4 and 5 tablespoons of salt. Using a digital multimeter tester, the output voltage and current were observed at least three times from three similar set-ups.
Fuel Cell Set-up. The number of fuel cell and the connectivity between cells was studied. A total of nine set-ups were developed to determine which set-up produced a higher power output.
Acceptability of the Device. The different mixes (especially the use of different liquids) was examined for acceptability. This considered the
manageability of the device considering the liquid used. Cost-effectiveness was also taken into consideration in the acceptability evaluation.
Figure 2: (Top) Designing device’s enclosure using 3D Builder App. (Bottom) Printing of the metal battery enclosure using Flagforge 3D printer
3.3 Design and construction of Enclosure
The optimal design of mixture, size of electrodes, and the desired number of fuel cell including its circuitry was the basis of the enclosure design. The printed circuit board (PCB) layouting utilized Proteus application on PC to simulate the
performance of the designed circuit. The enclosure of the metal-air battery was constructed with the aid of a Flashforge 3D printer and an acrylic glass for the lamp enclosure.
Figure 3: PCB Layout Using Prosteus Application
3.4 Data Analysis and Presentation
Data were presented in tables, graphs and pictures/images. Means, standard
deviation and frequency counts and relative frequency values were used to summarize the data gathered. A one-way ANOVA and a post-hoc Tukey HSD test were performed to determine the differences between groups.
Acceptability of the developed alternative device based on an assessment of 35 potential device users was conducted. The assessment was made in terms of overall appearance, functionality/operability, manageability, and cost.
4. Results and Discussion
The end-goal of the project study is to develop a prototype alternative liquid- water-based power source utilizing the electrolytic cell battery technology. In the search for higher voltage and current output, several alternative electrolyte, and metal as electrodes were examined.
Electrical energy is produced in many forms such as through combustion, mechanical movement, and photosynthesis (Battery University, 2017a). Electrical energy generation of batteries is produced by an electrochemical reaction between two metals having different affinities (ibid) such as zinc and copper. When the metals (the electrodes) are exposed to a type of liquid (usually acid) voltage is developed between them as part of ion transfer (ibid). The energy produced in the process comes from the chemical change in dissolving the metal into the acid termed as redox reaction (Bewick et al., 2019; Bates, 2012; Bertrand, nd).
4.1 Electrode Performance Assessment
The project utilized copper and zinc as the battery electrodes. Sourced from junk materials, it was prepared in two different sizes to check its effect on power generation.
With the amount of electrolyte (water-salt solution) remained the same, the produced voltage and current differ slightly in terms of value. Data shown in Table 1 suggests that the size of electrodes influences the amount of voltage generated significantly.
On the other hand, the current produced is slightly different from each sample group but the difference was not statistically significant.
The battery tested generates electricity through an electrochemical
reaction. With elements involved having larger surface area improves the reaction process (Papiewiski, 2018; Susanto, 2017).
Increasing the surface area of anodes (zinc or aluminum) and maintaining the distance between electrodes increases current while the higher surface area of the zinc anode in the shorter distance with the cathode generates higher voltage and current (Susanto, 2017). In the study, the distance between the electrodes was placed at the shortest possible to produce a smaller sized device. The little variation in the distance has not significantly affected the amount of current as shown in Table 1. On the other hand, the voltage produced is slightly higher but significantly different for set-up having larger zinc electrode as shown in Table 2.
The size of the metal electrodes will have some effects on the serviceability of the battery. The metal electrodes corrode as it reacts with the electrolyte solution which
makes larger sized electrodes longer time to consume. However, the rate of corrosion will depend on the kind of electrolyte
composition. In this paper, the zinc electrode will corrode until it stops giving off
electrons to copper (Bates, 2012). This means that larger electrodes will have a longer life span.
4.2 Type of Electrolyte and Energy Produced
An electrolyte is a chemical medium which allows the transfer of electrical charge between electrodes; commonly it is in forms of salt, acids or other bases in liquid or dry format (Bates, 2012; Battery University;
2017b; Schubert & Tsupova, 2017). In this project, six different liquid was examined, some mixed with salt to improve ionic composition. Four were mixed with table salt (NaCl) were the other two were used as is. Voltage and current produced were Table 1. Anode-Cathode Size and Output Voltage
Anode Cathode Water/Salt Ratio (g/g)
voltage v
σ p-value (Tukey HSD)
Copper Size (mm)
Zinc Size (mm)
(b) (c) (d) (e)
(a)100x67 100x33 350/60 0.7487 0.0006 0.622 *0.012 0.899 0.899
(b)100x33 100x67 350/60 0.7493 0.0006 0.102 0.283 0.622
(c)100x67 100x67 350/60 0.7507 0.0006 *0.004 *0.011
(d)100x33 100x33 350/60 0.7483 0.0006 0.899
(e)100x33 100x33 350/75 0.7487 0.0006
significant @ * 0.05 **0.01
Table 2. Anode-Cathode Size and Output Current Anode Cathode Water/Salt
Ratio (g/g)
current A
σ p-value (Tukey HSD) Copper
Size (mm)
Zinc Size (mm)
(b) (c) (d) (e) (a)100x67 100x33 350/60 0.5000 0.0100 0.899 0.735 0.735 0.899 (b)100x33 100x67 350/60 0.5033 0.0058 0.899 0.429 0.735
(c)100x67 100x67 350/60 0.5067 0.0058 0.195 0.429
(d)100x33 100x33 350/60 0.4933 0.0058 0.899
(e)100x33 100x33 350/75 0.4967 0.0058
significant @ * 0.05 **0.01
examined from six different battery set-up, maintaining type, size and distance of electrodes. Table 3 and 4 summarizes the result of the tests. The battery with
electrolyte using tap water, rainwater, and urine mixed with the same amount of salt have produced not significantly different voltage output of about 0.750, 0.747, and 0.753 volts respectively. The use of vinegar and Coca Cola resulted in slightly higher voltage output which is significantly higher than water (tap and rain) and oil with salt electrolyte as shown in Table 3.
Vinegar (Datu Puti brand) used in the project likely consists 3.97% acetic acid (Bacongco et al., nd) other brands ranges from 5-21% CH3COOH (Helmenstine, 2019) while its pH is around 2.5-2.7. Coca Cola like vinegar is acidic with pH of 2.6-2.7 (Cotton, 2011) and probably 80-89% of it is water. The acid in the two liquids makes it
qualify as an electrolyte for the battery. On the other hand, urine is about 91-96% water (Rose et al., 2015) and ammonium
bicarbonate is the dominant compound in it (Pettersson, 1994). The addition of NaCl was made to transform urine into an effective electrolyte. As urine ages, urea is biologically decomposed to ammonia which releases unpleasant odor (Andreev, 2017) making it unfavorable electrolyte.
The current observed to battery set- up having vinegar and Coca Cola as electrolyte is significantly higher than tap water, rainwater, urine, and cooking oil. On the other hand, the vinegar registered higher voltage and current than the Coca Cola set- up. Vinegar and Coca Cola will make the battery expensive than tap water or rainwater. The result observed did not consider long-term changes in the energy produced; chemical reaction changes with Table 3. Liquid-Salt and Output Voltage
Liquid Used Liquid/Salt Ratio (g/g)
voltage v
σ p-value (Tukey HSD)
(b) (c) (d) (e) (f)
(a) Tap Water 350/60 0.7500 0.010 0.864 0.899 0.899 **0.001 **0.001 (b) Cooking Oil 350/60 0.7433 0.006 0.899 0.581 **0.001 **0.001
(c) Rain 350/60 0.7467 0.006 0.864 **0.001 **0.001
(d) Urine 350/60 0.7533 0.006 **0.001 **0.001
(e) Vinegar 350/00 0.8100 0.010 0.864
(f) Coca Cola 350/00 0.8033 0.080
significant @ * 0.05 **0.01
Table 4. Liquid-Salt and Output Current Liquid Used Liquid/Salt
Ratio (g/g)
Current A
σ p-value (Tukey HSD)
(b) c (d) (e) (f)
(a) Tap Water 350/60 0.507 0.006 0.797 0.899 0.481 **0.001 **0.001 (b) Cooking Oil 350/60 0.513 0.006 0.481 0.082 **0.001 **0.001
(c) Rain 350/60 0.503 0.060 0.797 **0.001 **0.001
(d) Urine 350/60 0.497 0.006 **0.001 **0.001
(e) Vinegar 350/00 0.753 0.006 **0.001
(f) Coca Cola 350/00 0.650 0.001
significant @ * 0.05 **0.01
the changing chemical profile of electrolyte as it is used.
The effect on the energy produced versus the amount of salt added was evaluated. The increase in the liquid-NaCl ratio of 350/60 to 100/80 has resulted in an increase in voltage and current significantly.
4.3 Fuel Cell Design
The produced energy from the tested set-up was not sufficient to power a higher luminosity lamp or charge a mobile phone or the likes. The small energy produced requires setting-up series of these cells to provide more substantial energy. Various configurations were tested and a ten-cell set- up connected in series was more preferred.
4.3 Construction of Device Enclosure
The device enclosure was
constructed using a 3D printer; the rest of the device is made of acrylic glass. The
printing made use of Flashforge 3D printer taking at least two hours to complete. The device is comprised of three sections;
solution container, system circuitry, and the load section (see Figure 6). The upper part is the solution container (see Figure 5)
containing ten cells to hold ten separate batteries in which are connected in series (see Figure 4).
Figure 6. Main Device Enclosure Table 5. Circuit Output Using Different Connections
Liquid Used Liquid/Salt Ratio (g/g)
No. of Cells
Type of Connection
Output Voltage (v)
Output Current (A)
ave. σ ave. σ
Tap Water 350/60 10 Series 7.503 0.006 2.507 0.012
Tap Water 350/60 6 Series-Parallel 1.650 0.010 1.353 0.006
Tap Water 350/60 8 Series 4.503 0.015 2.103 0.006
Tap Water 350/60 2 Series 1.493 0.006 0.853 0.006
Tap Water 350/60 2 Parallel 0.757 0.006 0.203 0.006
Figure 4. Circuit Diagram of 10-Cell Battery Figure 5. Perspective View of 10-cell Container
Below the solution container is where the system circuits are found (see Figure 6). It is also where the USB charging port, the switch, battery, the LED indicator, and the PCB are kept. On the other hand, the lower portion of the device is an acrylic enclosure which is transparent. It is where the lamp will be located (see Figure 8).
Shown in Figure 7 is the block diagram of the entire device.
Figure 7. Block Diagram of the System
Figure 8. The Alternative Salt-Water Zinc- Cupper Electrolytic Battery Powered Lamp and Energy Source
4.4 Device Acceptability Assessment
Appearance. Table 6 shows a summary of the assessment made about the developed device. Its assessment made is not based on any existing lamp or equipment with similar capacity. Out of 35 respondents, around 83% rated it as very good or
excellent. Overall, the device enclosure and how it looks received a rating of 4.25.
Respondents critique was it seems fragile and may fall-off during use. Improving the rigidity of the device and the color choices may further improve the rating.
Functionality. The device received an excellent rating in terms of functionality.
It produced the desired/promised outcome says the respondents. The device is capable of lighting an LED lamp for more than 17 hours after which the solution needs to be replaced.
Table 6. Circuit Output Using Different Connections
Attribute Liquid Used
Rating Ave. Interpretation Overall
Appearance
- 4.25 Very Good Functionality - 4.51 Excellent Device
Management
*Tap Water 4.40 Very Good
*Rainwater 4.31 Very Good
*Oil 3.22 Good
*Urine 2.06 Bad Coca Cola 4.26 Very Good Vinegar 2.94 Good Cost
Efficiency
*Tap Water 4.20 Very Good
*Rainwater 4.20 Very Good
*Oil 3.23 Good
*Urine 4.49 Very Good Coca Cola 3.43 Good Vinegar 3.37 Good
Legend: 1.00 – 1.50 (Very Bad) 1.51-2.50 (Bad) 2.51-3.5 (Good) 3.51-4.5 (Very Good) 4.51-5.00 (Excellent)
Power Device Management. The smell of the vinegar and more specifically of the urine was the main issue raised by respondents. These were the reason why urine and vinegar as electrolyte material received a low rating of Bad and Good respectively. The other factor which made the device receive a Bad score was the hygienic aspect of urine.
Cost Efficiency. One major issue raised by the potential user of the device was the use of more expensive electrolyte such as cooking oil, vinegar, and Coca Cola (soda). The device costs around PhP 3,000.00, making it less appreciated by possible users. The total cost of the device may be further reduced when mas
manufactured.
5. Conclusion and Recommendation
5.1 . The device is capable of producing 7.5 volts which can run for 17 hours enough to light an LED lamp and cost
approximately PhP 3,000.00.
5.2 The type of liquid, the amount of salt mixture and the size of electrodes used produced very small variations in the output voltage and current. Differences which will have little bearing on the functionality of the device.
5.3 Among the different liquid (with salt) used as an electrolyte, the more
preferred is the tap water and rainwater due to availability and cost while the least preferred are the urine and vinegar because of its smell and hygienic consideration.
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