Perhaps the most important discovery in the unremitting race towards civilization came in 1831AD when a British scientist-Michael faraday came up with the concept of electromagnetic induction-the principle behind every electric transformer and generator. This principle was critical in enabling the transformation of electricity in mass into a very indispensable technological tool. This was after efforts by his peer Hans Christian Ørsted-a Danish scientist invented the concept of electromagnetism in 1821AD.
According to Wikipedia encyclopedia electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Long before electricity was viable for use people were aware of shocks. The ancient Egyptians knew of ‘shocking fish’ which they called the ‘Thunderer of the Nile’ which to them was the protector of other fish.
Living in the twenty first century, electricity can be regarded without doubt as the most critical and important energy and drive given that air is excluded. Virtually every device out there uses electricity, from small pretty watches to massive planes and ships, from that beautiful boutique shop with flickering little lights on the street to the houses we stay in. However the most important is the use of electricity to power the most cardinal of machines today-computers which include PCs, phones-which are very widely used, calculators and toys.
For electricity to be useful enough it had to be compacted so that it can be used. This led to the discovery of the battery by Alessandro Volta an Italian physicist. He named his battery the voltaic pile which would give out electricity when connected to other devices. The second type of battery-the electrolytic cell was pioneered by Volta and his colleague Luigi Galvani when they connected legs of frogs with a wire and they experienced what they termed as animal electricity-is this the reason why boys and girls feel high when they hold hands?
Today batteries come in many sizes and forms. At first there were those that would be used and dumped commonly known as dry cells-a product of voltaic pile. As time went by there arose the need of recharging batteries so that the cost of manufacturing new ones each day be reduced. Recharging was also beneficial to the environment owing to the fact that dumping of used dry cells was harmful seeing that they contain elements which are poisonous to humans and plants. An example of a voltaic dry cell is the zinc-carbon dry cell which is commonly used in torches, watches and radios.
When the current in the dry cell is exhausted, it cannot be recharged and that is why I call them one way batteries. The reaction that occurs to produce electric charge is anodic and cathodic i.e oxidation and reduction.
Anode (oxidation reaction, marked -)
Zn(s) → Zn2+(aq) + 2 e− [E° = −0.7626 V]
Cathode (reduction reaction, marked +)
MnO2(s) + H2O(l) + e− → MnO(OH)(s) + OH−(aq)
and the overall reaction:
4 Zn(s) + 8 MnO2(s) + ZnCl2(aq) + 9 H2O(l) → 8 MnO(OH)(s) + Zn(OH)Cl(aq) + 4 H2O(l) +4 ZnO(s) + HCl
From the overall equation one of the products is hydrochloric acid which is a very strong acid and a corroding agent that is harmful to the soil and contributes to soil acidity and this kills plants.
Principal of the two though is the electrolytic cell which most of us are familiar with in terms of phone batteries. Have you ever imagined how electricity can be used to produce electricity? That is what makes these batteries special. Stereotypically, we charge our batteries to store electricity but technically we don’t. Instead we use electricity to produce charge. These batteries contain at least two electrodes and an electrolyte mostly in form of paste. The electrodes are mostly made up of lithium, nickel or cadmium elements, lithium iodide, copper, carbon or zinc. Some even contain hydrogen.
When we buy a new iPhone 5s, one instruction is to charge it to full capacity first before use. The role of charging is to drive the chemical reactions within the battery to restore the normality of every element in the cell for full functionality. Therefore the role of charging the phone battery is not to store electricity for use but to drive chemical reactions. When we use the phone, a series of reactions normally oxidation and reduction occurs within and these produce the required amount of electricity or charge that powers the phone. When we hold those gadgets, it is not that everything is calm, but a lot of processes are going on simultaneously starting from the battery until a current is produced. As useful as these processes are, sometime they might go the wrong way if some elements do not balance in what is called a chemical equilibrium thus exploding the whole device which was the case with the high end galaxy note 7. An example of a reaction of a phone battery is given below using nickel cadmium cell.
The chemical reactions at the electrodes during usage or discharge are:
Cd +2OH- Cd(OH)2 +2e-
2NiO(OH) + 2H2O +2e- 2Ni(OH)2 + 2OH-
And the overall net reaction during usage or discharge is
2NiO(OH) + Cd + 2H2O 2Ni(OH)2 + Cd(OH)2
When the battery is drained and you connect the charger, the reverse just happens and everything is restored. Electricity is just used as a means of restoring normalcy. The reactions during recharging are:
Cd(OH)2 +2e- Cd +2OH-
2Ni(OH)2 + 2OH- 2NiO(OH) + 2H2O +2e-
2Ni(OH)2 + Cd(OH)2 2NiO(OH) + Cd + 2H2O
So when playing music or games on our phones, behind the scenes a lot is happening that we don’t normally understand or appreciate. Without these simple reactions it would be virtually impossible to compact a small efficient battery into a phone. We would be using phones directly connected to power grids.
The concept of overheating of the phone is too much speedy reactions occurring due to overuse of the device, this in some cases may be dangerous because the battery may explode. Using the phone while charging is not entirely safe because these processes are directly opposing g each other and that normally the recharge wins but it kills the battery. To be safe, use recharge and use again. Just be a little patient.
Electrode-normally a metal used to make contact with a nonmetallic electric conductor
Electrolyte-volatile nonmetallic electric conductor
Oxidation-loss of electrons
Reduction-gain of electrons
Cathode-positive electrode (in a voltaic/galvanic cell but negative in an electrolytic one)
Anode- negative electrode (in a voltaic/galvanic cell but positive in an electrolytic one)