Electric cell

Electrochemical cells are devices that use the energy produced by a spontaneous redox reaction to generate an electric current. The voltaic, cell, galvanic named after Luigi Galvani and Alessandro Volta, is an example of this type of cell. During the late 18th century, these scientists experimented with chemical reactions using electric current.

The anode and cathode are the two conducting electrodes in electrochemical cells. The anode is the electrode where oxidation takes place. A cathode is an electrode that undergoes reduction. Any sufficiently conducting material, including metals, graphite, semiconductor, and even conductive polymers, can be used to create electrodes. The electrolyte, which includes free-moving ions, sits between these electrodes.

Each metal electrode in the voltaic cell is immersed in an electrolyte solution. The anode will be oxidized, whereas the cathode will be reduced. The anode metal will oxidize, changing from a Zero oxidation state in solid form to a positive oxidation state, and becoming an ion. The metal ion in the mixture will accept one or more electrons from the cathode at the cathode, reducing the ion’s oxidation state to zero.

Electric cell chemical reaction

The voltaic cell operates based on a redox reaction, which is a simultaneous oxidation/reduction reaction. This redox reaction is made up of two halves. Copper and zinc are the redox partners in a conventional voltaic cell, as seen in the half-cell reactions:

Reaction at the Zinc anode electrode

Zn(s) = Zn2+ (aq) +2e–

Reaction at the Zinc cathode electrode

Cu2+ (aq) + 2 e– → Cu(s)

 The cells are constructed in separate beakers. The metal electrodes are immersed in electrolyte solutions. Each half-cell is connected by a salt bridge, which allows for the free transport of ionic species between the two cells. When the circuit is complete, the current flows and the cell produces electrical energy.

The anode is zinc, as well as the cathode is copper, therefore copper rapidly oxidizes zinc. Sulfates of the corresponding metals are the anions in the solutions. The electrochemical reaction occurs when an electrically conducting device joins the electrodes:

Zn + Cu2+ → Zn2+ + Cu

When the zinc electrode is oxidized, it produces two electrons, which go through the wire to the copper cathode. The electrons then seek the Cu2+ in solution, reducing copper to copper metal. The zinc electrode will be employed during the process, and the metal will reduce in size, whilst the copper electrode will grow in size due to the deposited Cu. To maintain the charge moving through the cell, a salt bridge is required. Without a salt bridge, the anode’s electrons would accumulate at the cathode, causing the reaction to stall. 

Anode

During an electrochemical process, the anode is the negative electrode that releases electrons to the external circuit and oxidizes.

Anode materials should have an efficient reducing agent, good conductivity, stable, high coulombic output, low cost, ease of fabrication metals such as Zinc and Lithium are often used as anode materials.

Cathode

The positive or oxidizing electrode, the cathode, receives electrons from the external circuit and reduces them throughout the electrochemical reaction.

Cathode materials should have an efficient oxidizing agent, ease of fabrication, low cost, stable when in contact with the electrolyte, useful working voltage, metallic oxides such as are often used as cathode materials.

Electrolyte

 The electrolyte is the medium that facilitates ion transport between a cell’s cathode and anode. Electrolytes are commonly conceived of as liquids containing dissolved salts, alkalis, or acids that are required for ionic conduction. Many batteries, including traditional (AA/AAA/D) batteries, however, contain solid electrolytes that act as ionic conductors at ambient temperature.

Electrolyte materials should have a non-reactivity with electrode materials, strong ionic conductivity, no electric conductivity, properties resistance to temperature fluctuations, safeness in handling, low cost, aqueous solutions such as dissolved salts, acids, and alkalis are often used as electrolytes.

Types of Electrochemical Cells

1. Galvanic cell or voltaic cell

When electrons shift from various species through a spontaneous redox reaction, energy is released. When the process is split into two half-reactions, oxidation and reduction, this energy can be employed to complete activities. These two reactions take place in two different containers, with a wire acting as a bridge between them to transport electrons from one to the other. A galvanic or voltaic cell is generated as a result of this.

Advantages of a galvanic cell

1. Most of them can be charged.

2. These are easily available and take less effort for manufacturing

3. They last for a long period

Disadvantages of galvanic cells

1.  Some of the galvanic cell batteries are very heavy.

2.  Some of them are more expensive than electrolytic cells.

3.  Some of the batteries show spoilage or rusting very easily.

2. Electrolytic cell

     These are the electrochemical cells that use electrical energy to drive a nonspontaneous reaction. Chemical substances, such as water, can be decomposed into hydrogen and oxygen using these. The method of electrolysis is used to decompose the material. To perform electrolysis, electrolytic cells require a DC power supply, two electrodes, and an electrolyte.  

Application  

 Electroplating

 Batteries

 Electrowinning of electro-refining

 Oxygen production

 Hydrogen fuel

Conclusion

Electric cells are very useful in carrying electrical power. The electrical power is stored in the chemical form and used whenever needed. Today every portable gadget has batteries in it and the cells are a great topic for research. Most of the research is being done to make batteries lightweight and long life.    

The anode is the negative terminal of the battery and the cathode is the positive terminal of the battery. And the electrolyte is the chemical fluid that is present in the battery.