Transcript Batteries and Chemistry

Batteries and Chemistry
AP Chemistry Final Project
Derek Leung
Essential Questions
• How do traditional, rechargeable, and lithiumion batteries work?
• How do chemical concepts explain the
mechanisms behind batteries?
• What advancements are being made for the
future of batteries?
Thermodynamics and Energy
• Batteries convert chemical potential energy
into kinetic energy which can do work.
– Conservation of Energy (1st Law of
Thermodynamics)
• Relationship between Free Energy and voltage
– ΔG°cell = −nFE°cell
– If E°cell > 0, spontaneous (galvanic cell)
– If E°cell < 0, nonspontaneous
History of the Battery
• 1786, Luigi Galvani discovered
“animal electricity”
• 1800, Alessandro Volta built
the first practical battery
• 1859, Gaston Plante invented
the first rechargeable battery
with lead acid
• 1899, Waldmar Jungner
invented the NiCd battery
• 1991, Sony commercialized
the lithium-based battery
Lemon Battery Demonstration
• Classic Example of Electrochemistry
• Metals Used: Zinc (Zn) and Copper (Cu)
• Half Reactions
– Cathode: 2H+ + 2e-  H2 (reduction)
– Anode: Zn  Zn2+ + 2e- (oxidation)
Is essentially....
Traditional Battery
• A battery is composed of many voltaic cells.
• Most common non-rechargeable battery nowadays is the
alkaline battery
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Reaction between Zinc and Manganese (IV) oxide
Anode: Zn(s) + 2OH-(aq)  ZnO(s) + H2O(l) + 2e- [E°=-1.28]
Cathode: 2MnO2(s)+H2O(l) +2e-Mn2O3(s)+2OH-(aq) [E°=+0.15V]
E°cell = E°cathode - E°anode = 0.15V – (-1.28V) = 1.43V
• In the case of AAA, AAA, C and D batteries, the more cells, the
more current the battery can provide. Voltage stays the same.
– Analogous to a water pipe
Rechargeable Battery
• Rechargeable batteries work because they use
reactions that are reversible.
– Reactants <-> Products
• External work needed
Memory Effect
• A con of rechargeable batteries
such as nickel cadmium and
nickel-hydride batteries
• With each recharge, the
battery holds less charge
• Overcharging affects crystalline
structures
Lithium Ion Battery
• Lithium ions are a type of rechargeable battery with high
energy density and tiny memory effect.
– Cathode: Metal oxide
– Anode: Carbon
– Electrolyte: lithium salt in organic solvent
• Cons?
Non-rechargeable vs. Rechargeable
• What happens when one attempts to recharge
a traditional battery?
– Actually, one can recharge a regular battery.
– However... there are concerns.
• Efficiency
• Voltage and Safety
Future of Batteries
• Disposal and Recycling
– Alkaline batteries can be disposed.
• Mercury and heavy metals
– Lithium Ion batteries should be recycled.
– Car batteries should be brought to waste management centers.
• Improved performance and safety
– Lithium-air batteries
– Solid-state batteries
Works Cited
"Battery Care, Use and Disposal | Duracell Batteries." Duracell
Batteries. N.p., n.d. Web. 25 May 2016.
Brown, Theodore L., H. Eugene LeMay, and Bruce Edward. Bursten.
"Chapter 20 Electrochemistry." Chemistry: The Central Science.
Upper Saddle River, NJ: Prentice Hall, 2000. 751-803. Print.
Buckle, Kenneth. "How Do Batteries Store and Discharge Electricity?”
Scientific American (2006): n. pag. Print.
Lerner, Michael. "How Do Rechargeable (that Is, Zinc-alkaline or
Nickel-cadmium) Batteries Work and What Makes the Reactions
Reversible in Some Batteries, but Not in Others?" Scientific
American (1999): n. pag. Scientific American. 21 Oct. 1999. Web.
25 May 2016.
Roberts, Royston M. "The Electric Battery and Electromagnetism.”
Serendipity: Accidental Discoveries in Science. New York: Wiley,
1989. 16-18. Print.