EMS630U Fundamentals of Electrochemical Engineering Assignment Sample

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Introduction to Fundamentals of Electrochemical Engineering Assignment

Lab 1: Electrochemical Potentials

Main objective

The main objective of this:

• To know the electrochemical cells, calculating cell potentials
• To compare the Nernst equation as well as the effect of concentration and pH on the voltage of differential redox reactions.

Main formulas for the experiment

The equation of cell potential is

E° cell = E° cathode - E° anode

This formula can effectively calculate the standard voltage of the electrochemical cell.

Besides, Nernst Equation

E = E0 - (0.059/ n) log [oxidant/ reductant]

This needs to happen at 25 degrees centigrade.

Through this equation the effects of concentration on cell potential can be observed.

After that comes,

Gibbs free energy

ΔG = - nFE

When the ΔG is negative then this means the reaction shows spontaneity.

Difficult concept to run in the experiment

The most difficult to understand this type of experiment is the Nernst equation that defines the voltage of an electrochemical cell when ions are not under standard conditions. This equation is used when it is necessary to know how the ionic concentrations behave in practice, for example in batteries, and sensors where the concentrations are never ideal. It has features of logarithmic calculations that may not be easily understandable by most people especially those with poor experience in exponential relations (Warburton et al. 2022). In addition, the equation involves cubed temperature, and hence an accurate measurement of the temperature is required to get accurate results. One of the key challenges in electrochemistry is determining which segment of an electrochemical cell is most affected by changes in concentration. An important observation is that even small variations in ion concentration can cause significant changes in cell potential, making it essential to understand how redox reaction equilibrium shifts under different conditions. The Nernst equation plays a crucial role in electrochemical analysis, as it helps explain the relationship between ion concentration and electrode potential. This understanding is vital for practical applications such as corrosion prevention, battery design, and energy storage systems, and is often explored in detail through academic support resources like Online Assignment Help UK to enhance conceptual clarity and problem-solving accuracy.

EMS630U Fundamentals of Electrochemical Engineering Assignment Sample

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One daily life example for the experiment

An example is a battery in a remote, before using the remote, a battery has to be inserted into it and consequently, deceased batteries have to be removed from the remote and replaced with a fresh one. Batteries work in the same way as the electrochemical cells; they produce electricity using chemical reactions.

In a dry cell, MnO₂ and Zn comes into reaction where the chemical reaction is as follows.

Zn is oxidized and MnO₂ is reduced. The reaction between them occur as the Zn loses electrons meaning that it will be oxidized MnO₂ gains electrons hence it will be reduced. This gives a voltage that operates the remote control unit (Casebolt et al. 2021). Finally, the chemical combinations wear out and the battery is now drained. Batteries and their operations are best explained through this experiment so as to determine the reasons behind their failure.

Propose and solution of the numerical exercise

The problem:

There is a voltaic cell made of Zn²⁺| Zn and Cu²⁻| Cu half-cells. The standard reduction potentials are:

Zn² + 2e⁻ – Zn (E° = - 0.76 V)

Cu² + 2e⁻ – Cu (E° = + 0.34 V)

What can be the standard cell potential (E°cell) and the cell potential if [Zn²⁺] = 0.1 M and [Cu²⁺] = 1.0 M be questions.

The solution:

E° cell = E° cathode - E° anode

E° cell = (0.34 V) - (- 0.76 V) = 1.10 V

There the standard voltage is 1.10 V.

(b) Using the equation of Nernst:

E = E° - (0.059/ n) log ([Zn²⁺] / [Cu²⁺])

E = 1.10 - (0.059/ 2) log (0.1/ 1.0)

E = 1.10 - (0.059/ 2) (-1)

E = 1.10 + 0.0295

E = 1.13 V

Since the concentration of Zn²⁺ is lesser here the voltage increases to 1.13 V.

Lab 2: Batteries

Main objective

• To know about batteries and their working principles.
• To analyze charge and discharge cycles and measuring energy storage along with appreciating and making this familiar with properties like Coulombic efficiency.
• To understand the specific capacity and energy density.

Main formulas for the experiment

The Charge stored (Q):

Q = I * t

This formula calculates the Q value, which represents the charge of the battery that is stored.

Therefore, Energy stored (E):

E = V * Q

This equation points out the total energy in joules and follows the CE also.

Therefore, Coulombic Efficiency (CE):

CE = (Q discharge / Q charge) * 100

It is the quotient made out of the stored charges returned in discharging and charges put in during charging.

Then, Specific Capacity (C):

C = Q / m

This is the measure of the amount of energy that is present in a battery of a given mass of the material used for creating the battery.

Difficult concept to run in the experiment

Most complex in this experiment would be Coulomb efficiency (CE), which indicates the ability of a battery in storing and releasing the charge in both charging and discharging cycles. When CE is high, this means it is a good battery as it is able to capture and generate energy, while if CE is low, energy is lost and the battery has a poor performance and cannot last long. This loss of energy could be as a result of side reactions, internal resistances, and degradation of the electrodes (Tang et al. 2023). This is because a comprehension of the electrochemical reactions involving metal ions, ion transport and the properties of the metal require some basic understanding of chemistry. Furthermore, batteries in the real environment are never perfect and due to various factors it is virtually hard to determine the losses in efficiency. Temperature fluctuations, growth of crack and other external factors make it irrational to precisely measure CE (Yang et al. 2024). Underpinning this is a crucial notion that should be understood better for AMAs performance improvements in communication devices such as smartphones, electric cars, and renewable energy storage devices that directly relate to efficiency and durability.

One daily life example for the experiment

An example includes the battery of the mobile phone. It charges when connected to the source of electricity or power outages. It discharges when being used. When the battery is old, charging also takes longer time, while the phone drains even with a small load faster (Liu et al. 2021). This is because Coulombic efficiency is affected and therefore entity 2 loses the energy stored in the battery. Understanding this experiment helps in the enhancement of battery duration and effectiveness of energy in the electrical appliances.

Propose and solution of the numerical exercise

Problem:

There is a battery that draws a current of 0.5 A for 2 hours. It subsequently discharged at a current of 0.4 A for 1.8 hours As indicated in the description above then it is recharged to 4V for 8 hours at a current of 0.4 A As it prepares to be tested in the subsequent cycles Afterwards, it is recharged to 4V for 8 hours in a current of 0.4 A

This has significant facts concerning the charging process and the ability to store the amount of charge, and the ability to discharge the amount of charge during the discharging process. In addition, it will be advantageous to know what will happen with the Coulombic Efficiency.

The solution:

(a) The charge stored upon charging:

Q charge = I * t

Q charge = 0.5 * (2 * 3600)

Q charge = 0.5 * 7200 = 3600 C

(b) The charge retrieved upon discharge:

Q discharge = 0.4 * (1.8 * 3600)

Q discharge = 0.4 * 6480 = 2592 C

(c) The Coulombic Efficiency:

CE = (Q discharge / Q charge) * 100

CE = (2592 / 3600) * 100

CE = 72%

This means that, during the charging process, only 72% of the lithium ions are actually inserted into the separator, while the remaining 28% of the lithium ions are presumably lost as heat or as a result of internal electrical resistance.

Lab 3: Corrosion

Main objective

• To investigate the corrosion of different metals under various environments.
• To determine the corrosion rate using weight loss and electrochemical methods.
• To determine how corrosion is affected by the ionic strength of the media and the pH.

Main formulas for the experiment

Corrosion Rate (Gravimetric Method):

The Corrosion Rate = ((Weight Loss * 365) / (Area * Time (days)))

It measures the extent of corrosion of a metal in milligrams per square centimeter per year.

The Current Density (Electrochemical Method):

j = j₀ [exp (αₐFη /RT) - exp (- αcFη/ RT)]

This is the formula that relates current with voltage in corrosion.

The Tafel Equation:

η = (RT / αₐF) ln jₐ - (RT / αₐF) ln j₀

It is applied in determining corrosion potential and rate from the experimental results.

Difficult concept to run in the experiment

In this experiment, the most complicated principle is electrochemical corrosion measurement whereby one is required to determine how metals corrode depending on the environment prevalent at a given station. The most significant barrier is to understand the Tafel equation since it involves dealing with logarithmic functions to estimate the corrosion rates (Ramón et al. 2022). Corrosion also has a direct dependence on metal potential and current; slight shifts in the voltage cause a marked difference in the rate of corrosion of the metal. Another issue which complicates the analysis of the processes occurring on the metal surface is that reduction and oxidation processes are simultaneous. There are several agitative factors including pH, oxygen and salts among others that may cause both acceleration and retardation of corrosion making it very difficult to predict or even control for that matter (Anantharaj et al. 2021). This information turns out to be very useful in industries such as marine engineering, construction especially for engineering structures, and space engineering where avoiding corrosion is as important as the preserve of air.

One daily life example for the experiment

A good example is the state in which iron fences may rust. When rain and air get in contact with iron, they act upon it in presence of oxygen. They form iron oxide commonly known as rust which degrades the quality of the metal. In sea-close cities people get corroded faster as they contain a pinch of salt in the environment (Kuratani et al. 2022). As for this experiment, it shows the kind of precautions undertaken in an attempt to eradicate rusting such as painting, galvanizing or using stainless steel. That is why the understanding of corrosion processes makes it possible to maintain infrastructures, avoid failures at bridges, pipelines, and even buildings.

Propose and solution of the numerical exercise

Problem:

In this experiment, 6 cm² of steel will be immersed in 1M NaCl for ten days. Initially, the weight of the specimen is 10.5 g and the weight after exposure is 10.45 g. The problem is about what is the corrosion rate in mg/cm²·year of the corrodes specimen as determined from the mass loss measurements. If the same steel sample is exposed to the acidic water and corroded at the rate double, to what weight would it be reduced after 10 days.

The solution:

(a) The calculation of Corrosion rate:

Weight Loss = 10.5 - 10.45 = 0.05 g = 50 mg

Corrosion Rate = (Weight Loss * 365) / (Area * Time)

= (50 * 365) / (6 * 10)

= 18250 / 60 = 304.2 mg/ cm²·year

The corrosion rate of the steel is 304.2 mg/ cm²·year in NaCl solution.

(b) New Weight after 10 Days in Acidic Water:

As corrosion is twice as fast, the new weight loss is the following:

New weight loss,

50 * 2 = 100 mg

= 0.1 g

New Weight = 10.5 - 0.1

= 10.4 g

As such, after 10 days of treatment in acidic water, the steel will have a mass of 10.4 g.

Lab 4: Electrolytic Cells

Main objective

• The objective of the electrolysis experiment is to determine the way electrical energy is used to induce chemical change.
• To measure the voltage required to electrolyse water, and identify hydrogen and oxygen gas with an electrolytic cell.

Main formulas for the experiment

The Electrolysis of Faraday's Law:

m = (Q * M) / (n * F)

The formula calculates the amount of any substance that is deposited or liberated through the process of electrolysis.

Charge (Q),

Q = I * t

Below is one of the formulas that finds the total charge passed through the given system. Volume of Gas Produced (at STP):

V = n * 22.4

It is used to find the volume of the gas that is produced, and the other one is the number of moles of the gas.

The energy consumed,

E = V * I * t

It is applied to determine the energy used in the process of electrolysis.

Difficult concept to run in the experiment

Among these, the clearest but hardest to grasp is a notion found within the first idea, namely the efficiency of electrolysis and overpotential concerning the capacity with which electrical energy splits water into hydrogen and oxygen. In theory, electrolysis will begin with the voltage that has been set, nevertheless, in reality, additional voltage is applied because of resistance, side reactions, and overpotential (Jiang et al. 2022). It is true that there is overpotential because the process occurring at the surface of both the electrodes is not an efficient one and therefore loss in energy occurs. Additionally, the efficiency is vested on the type of electrodes applied, which may either be platinum or graphite. This is because Platinum does not have high or overpotential because it is very conductive while Graphite may require a bigger voltage. Secondly, the efficiency is also a factor of the concentration of the electrolyte, temperature, and contamination (Cavaliere, 2023). Information concerning these matters is crucial towards enhancing the efficiency of generating hydrogen, which is an essential element in renewable energy and fuel cells, whereby entropy and the loss of energy should be kept to the lowest level for purposes of efficacy.

One daily life example for the experiment

One is a typical example of water electrolysis used in the production of hydrogen fuel. Water electrolysis dissociates H₂O into H₂ (hydrogen) and O₂ (oxygen). It is well-known that hydrogen gas is used in the operation of hydrogen-fueled automobiles and rockets. It is a known fact that hydrogen combusts rather irresponsibly that is far from pollutants, and therefore it contributes to green energy (Johnson, 2021). The experiment helps one to realize how electricity is utilized to turn water into fuel. Hydrogen is one of the future energies and electrolysis is a key to producing it.

Propose and solution of the numerical exercise

Problem:

3 Amperes are passed through the electrolytic cell during the electrolysis of water for one hour.

The problem is the charge which flows through the solution is called electrolytic current, the amount of hydrogen gas is produced and the volume of hydrogen gas collected at STP.

The solution:

(a) The calculation of Charge:

Q = I * t

Q = 3 * (1 * 3600)

Q = 10,800 C

In this case, 10,800 C charge passes through the solution.

(b) The calculation of Moles of H₂ Formed:

According to Faraday's Law,

n = Q / (n * F)

For H₂ production, n = 2 electrons per mole.

n = 10,800 / (2 * 96,485)

n = 0.056 moles of H₂

(c) The volume of H₂ at STP:

V = n * 22.4

V = 0.056 * 22.4

V = 1.25 L

So, if one hour is taken as the basis, about one-and-a-quarter liters of hydrogen gas is formed.

Reference List

Journals

• Anantharaj, S., Noda, S., Driess, M. and Menezes, P.W., 2021. The pitfalls of using potentiodynamic polarization curves for tafel analysis in electrocatalytic water splitting. ACS Energy Letters, 6(4), pp.1607-1611.
• Casebolt, R., Levine, K., Suntivich, J. and Hanrath, T., 2021. Pulse check: Potential opportunities in pulsed electrochemical CO2 reduction. Joule, 5(8), pp.1987-2026.
• Cavaliere, P., 2023. Thermochemical Water Splitting Cycles. In Water Electrolysis for Hydrogen Production (pp. 105-157). Cham: Springer International Publishing.
• Jiang, S.P., Li, Q., Jiang, S.P. and Li, Q., 2022. Fuel Cell Thermodynamics. Introduction to Fuel Cells: Electrochemistry and Materials, pp.27-68.
• Johnson, J.C., 2021. Development of a Mathematical Model for Galvanic Cells.
• Kuratani, K., Fukami, K., Tsuchiya, H., Usui, H., Chiku, M. and Yamazaki, S.I., 2022. Electrochemical polarization part 1: fundamentals and corrosion. Electrochemistry, 90(10), pp.102003-102003.
• Liu, Y., Deng, Q., Li, Y., Li, Y., Zhong, W., Hu, J., Ji, X., Yang, C., Lin, Z. and Huang, K., 2021. CoSe@ N-doped carbon nanotubes as a potassium-ion battery anode with high initial coulombic efficiency and superior capacity retention. ACS nano, 15(1), pp.1121-1132.
• Newman, J. and Balsara, N.P., 2021. Electrochemical systems. John Wiley & Sons.
• Ramón, J.E., Martínez, I., Gandía-Romero, J.M. and Soto, J., 2022. Improved Tafel-based potentiostatic approach for corrosion rate monitoring of reinforcing steel. Journal of Nondestructive Evaluation, 41(4), p.70.
• Sullivan, I., Goryachev, A., Digdaya, I.A., Li, X., Atwater, H.A., Vermaas, D.A. and Xiang, C., 2021. Coupling electrochemical CO2 conversion with CO2 capture. Nature Catalysis, 4(11), pp.952-958.
• Tang, Z., Zhou, S., Huang, Y., Wang, H., Zhang, R., Wang, Q., Sun, D., Tang, Y. and Wang, H., 2023. Improving the initial coulombic efficiency of carbonaceous materials for Li/Na-ion batteries: origins, solutions, and perspectives. Electrochemical Energy Reviews, 6(1), p.8.
• Wang, D., Kijkla, P., Saleh, M.A., Kumseranee, S., Punpruk, S. and Gu, T., 2022. Tafel scan schemes for microbiologically influenced corrosion of carbon steel and stainless steel. Journal of Materials Science & Technology, 130, pp.193-197.
• Warburton, R.E., Soudackov, A.V. and Hammes-Schiffer, S., 2022. Theoretical modeling of electrochemical proton-coupled electron transfer. Chemical reviews, 122(12), pp.10599-10650.
• Yang, Y., Wu, C., He, X.X., Zhao, J., Yang, Z., Li, L., Wu, X., Li, L. and Chou, S.L., 2024. Boosting the development of hard carbon for sodium‐ion batteries: strategies to optimize the initial coulombic efficiency. Advanced Functional Materials, 34(5), p.2302277.