1. Rechargeable batteries!
By: Jasmina (Nina) Jovanovic

2. Chemistry behind batteries:
Battery – a group of two or more galvanic cells connected in series
1. Disposable batteries - primary cell ( cannot be recharged)
2. Rechargeable batteries- secondary cell ( can be recharged)
A galvanic cell - spontaneously produce electric current
Half cell= electrode + electrolyte
A battery is a group of two or more galvanic cells connected in series. Each galvanic cell consists of two connected half cells and its function is to spontaneously produce an electric current. The half cells consist of an electrode and an electrolyte. A battery can either be a disposable battery or a rechargeable battery. Primary cells cannot be recharged and they are used in disposable batteries, where as the secondary cell can be recharged and they are used in rechargeable batteries.

3. Chemistry behind batteries:
A battery with two electrodes  voltaic cell.
Electrical current runs in between the battery’s two electrodes
Electrolyte - in liquid or solid state
Electrolyte- contains ions
A battery that contains two electrodes is called a voltaic cell, and an electrical current that is caused from the voltage difference between anode (-) and cathode (+) runs in between the battery’s two electrodes. “Electrolyte” is a chemical that is in either liquid or solid state, and this is where the voltage runs through.

4. Chemistry behind batteries:
What are rechargeable batteries?
Known as storage batteries due to their ability to accumulate and store energy
Group of one or more electrochemical cells
Known as secondary cells since its electrochemical reactions are electrically reversible
Standard power source for today’s products
Exist in many shapes and sizes
Rechargeable batteries also known as storage batteries due to their ability to accumulate and store energy. They are a group of one or more electrochemical cells. Since its electrochemical reactions are electrically reversible they are also known as secondary cells. Rechargeable batteries are widely used and due to their convenience they are definitely becoming more preferable. They are the standard power source for today’s products, mostly for portable appliances such as cell phones, computers, and digital cameras and they exist in many shapes and sizes.

5. Chemistry behind batteries :
Batteries made up of plates
Device connects = electrons move to the +’ve side Secondary cell:
External source of electrical energy is required
Redox reaction needs to be reversed
Allows it to be reused
Reactive chemicals that are separated by barriers help the batteries to be made up of plates. Polarizing these barriers causes then the electrons to all come together on one side causing it to be negatively charged and the other side that they left, it causes it to become positively charged. The electrons start moving to the positive side as soon as the device is connected. While this is happening, an electrochemical reaction also occurs inside the batteries at the same time where it causes the replenishment of electrons. Therefore this whole process results in a chemical process that creates electrical energy. However, to recharge a secondary cell the redox reaction that is occurring in the cell needs to be reversed using the external source of electrical energy which then this process regenerates the reactants. The process of recharging batteries allows the battery to keep on producing electricity and it allows it to be reused at any time.

6. Electrons flow from one electrode to another through an electrolyte
Current produces through an electrochemical reaction involving anode, cathode, and electrolyte
Electrons flow from one electrode to another through an electrolyte
Outside source is used to apply the electrical energy to a secondary cell
(-) to (+) electron flow that happens during discharge is reversed, and the cell’s charge is restored.
The rechargeable batteries or secondary cells produce current the exact same why as disposable batteries (primary cells). The way the current produces is through an electrochemical reaction that involves an anode (negative end), cathode (positive end) and electrolyte (chemical which is either in liquid or solid state). The electrochemical reaction causes the electrons to flow from one electrode to another through an electrolyte. The battery consists of (-) and a (+) terminals which give an outlet and inlet for the electrons to flow. However in the rechargeable batteries the reaction is reversible. The outside source is used to apply the electrical energy to a secondary cell, after this process the (-) to (+) electron flow that happens during discharge is reversed, and the cell’s charge is restored. Overall after reversing the chemical reaction the chemical elements involved are restored to their original form due to the reversed electron flow which then the battery starts the process again.

7. The Different Types of Rechargeable Battery: -Nickel Cadmium (NiCd) -Nickel Metal Hydride (NiMH) -Lithium-ion (Li-ion) - Sealed Lead Acid (SLA)
Better option than disposable batteries
Reduce the amount of waste generated
There are a lot different types of rechargeable battery and each of them have a little difference due to their own internal chemistry. The different types of rechargeable battery are: -Nickel Cadmium (NiCd)  the oldest type Cell voltage: Energy Density (MJ/kg): least expensive, least temperature sensitive. - Many recharge cycles, and Cadmium is environmental hazard -Nickel Metal Hydride (NiMH) Cell voltage: Energy Density (MJ/kg): less money effect than NiCd - Fewer recharge cycles than NiCd and self discharge is faster than NiCd Lithium-ion (Li-ion)  new type Cell voltage: Energy Density (MJ/kg): no memory effect - very low self-discharge and many recharge cycles - expensive - Sealed Lead Acid (SLA) Cell voltage: Energy Density (MJ/kg): Moderately expensive, Moderate rate of self discharge. -Higher discharge rates – a great loss of capacity. - no memory effect
Rechargeable batteries don’t last indefinitely but they are still a better option than disposable batteries, because one rechargeable battery can substitute for hundreds of single use batteries which reduce the amount of waste generated.

8. Advantages of using Rechargeable batteries:
Help the environment
Convenience
Cost efficient
Better performance
Rechargeable batteries have more advantages than disadvantages. Some of the advantages of using rechargeable batteries are: Help the environment- because they can be used again instead of throwing them away and filling up the landfills. Most batteries release harmful metals such as mercury, cadmium and lead into the environment but since rechargeable batteries are easy to recycle and can be recharged, they contribute less waste to landfills.
Convenience- they can last up to 5x longer on each charge than disposable batteries. Especially when used with high drain devices, example: digital cameras
Cost efficient- instead of buying batteries constantly using, a one that’s rechargeable is more beneficial. They have higher initial cost but then it can be used many times and recharged cheaply. They are capable of being used more than 500 times.
Better performance- rechargeable batteries use 1.2 volts of energy entire time when used while the disposable batteries start at 1.5 volts and decrease until they die.

9. Disadvantages of using rechargeable batteries:
Charging
Hazard
Uses
Rechargeable batteries have more advantages, however there are few disadvantages as well. Some of the disadvantages of using rechargeable batteries are: Charging- sometimes charging takes a while, and it can be a strong disadvantage if some of the other devices have to be powerless in order for the batteries to recharge. Hazard – Some rechargeable batteries (mostly nickel- cadmium variety), contain chemicals that are more dangerous than the ones that are inside alkaline batteries .
Uses-Some types of batteries are useful only with certain devices.

10. Capacity of a standard rechargeable battery before it has to be recharged:
Battery Type
Total Capacity
Self-Discharge Rate
Use Charactersitics
Nickel-Metal Hydride (NiMH)
Up to 1,000, AAA. Up to 2,700 mAh, AA. Available capacities vary widely. Check the mAh rating before you buy.
Does not hold charge well over long periods. Loses 4 percent per day1, much more in warm temperatures.
Works well in devices that require sudden high amperage discharge, such as digital cameras. Also works well in most other devices
Low Self Discharge Nickel-Metal Hydride (LSD NiMH)
Up to 800, AAA. Up to 2,000, AA Almost all LSD batteries sold have close to these capacities.
Holds charge well over long periods. Loses 15 percent per year2, very slightly more in warm temperatures.
Works well in devices that require sudden high amperage discharge, such as digital cameras. Also works well in most other devices.
Nickel-Cadmium (NiCd)
Up to 350 mAh, AAA. Up to 1,000 mAh, AA. Available capacities vary widely. Check the mAh rating before you buy.
Loses 1 percent per day3, slightly more in warm temperatures.
Does not work well in devices that require sudden high amperage discharges. Does not work well in digital cameras, but does work well in most other devices.
--> chart from the website This chart shows the comparison of the rechargeable batteries. The column of “use characteristics” shows that Nickel-Cadmium (NiCd) is the only one that differs in that column when compared to the other two.

11. Methods that should be used for disposing batteries:
Alkaline and carbon-zinc batteries, and individual NiMH batteries =disposed with the regular household trash.
Batteries that are before1996 ( large amount of mercury)=hazardous waste
Button batteries containing mercury oxide, silver oxide and zinc-air cells, and sealed lead-acid batteries=hazardous waste.
Avoid disposing too many batteries, together at once
Car batteries that contain lead should be brought only to waste management centres.
There are a variety of different types of batteries, therefore they differ and should not be disposed in the same way. Some batteries such as Alkaline batteries (used to power radios, and appliances), and carbon-zinc batteries (used to power remotes, toys, etc.), can be disposed with the regular household trash. Individual NiMH batteries can as well be disposed with other household waste if the disposal service does not exist in the area. However if ten or more batteries are accumulated then it should be disposed in a secure waste landfill. Then there are some batteries that should be treated in a more reasonable way, in order to protect our environment. Household batteries that are manufactured before May 13, 1996 are said to contain 10 times more mercury than the batteries today. Any batteries that are before 1996 should be dropped off at a hazardous waste facility due to the large amount of mercury contained in those batteries. Button batteries containing mercury oxide, silver oxide and zinc-air cells, and sealed lead-acid batteries are considered to fall into the category of hazardous waste.
Car batteries that contain lead should be brought only to waste management centres, where they are going to be eventually recycled.
Disposing too many batteries at once should be avoided, because a reaction can occur if the dead batteries come in contact with each other.

12. Impact of the rechargeable batteries in portable electronic devices on society:
New electronics
No need for changing batteries constantly
Provides people with more powerful, reliable, and reusable-costing.
Many portable electronic devices use only rechargeable batteries
Helped many companies develop in many industries
The impacts of rechargeable batteries in portable devices on society are really strong. The rechargeable batteries have made the usage of electronic devices much easier to deal with, because these batteries provide us now with powerful, reliable, and reusable-costing. Many portable electronic devices, such as smartphone’s, laptops and MP3 players, use only rechargeable batteries, therefore these batteries made it possible for people to use these types of electronic devices. Not only does it allow us to produce new electronics but it is much easier to have rechargeable batteries that can be easily recharged at any time rather than continuously buying new, disposable ones. Moreover the rechargeable batteries has helped many companies develop in many industries, and as new electronics demand more from batteries, battery technology will also improve in future years, which will be even more beneficial.

13. Resources:
battery-disposal-methods/
power/rechbattinfo.htm
review.toptenreviews.com/battery-chargers- and-the-benefits-of-rechargeable- batteries.html
news/the-different-types-of-rechargeable- battery/