BATTERIES

• DIFFERENT TYPES OF CELLS?

  • non-rechargeable
  • rechargeable
  • fuel cells
• NON-RECHARGEABLE CELLS?

  ZINC-CARBON

  • Zn + 2NH3 + 2H+ + 2MnO2 -> Zn(NH3)2 (2+) + Mn2O3 + H2O

  ALKALINE

  • Zn + 2MnO2 + 2H2O -> Zn (2+) + 2OH- + 2MnO(OH)
• RECHARGEABLE CELLS?

  LEAD ACID

  • 6 cells
  • used in cars
  • DISCHARGE: PbO2 + 2H2SO4 + Pb -> 2H2O + 2PbSO4

  NICKEL/CADIUM

  • portable
  • DISCHARGE: 2NiO(OH) + Cd + 2H2O -> 2Ni(OH)2 + Cd(OH)2

  LITHIUM ION

  • laptops/ tablets/ phones
  • Li+ + CoO2 + e- ⇋ LiCoO2
  • Li+ + e- ⇋ Li
  • DISCHARGE: Li + CoO2 -> LiCoO2
• FUEL CELLS?

  ALKALINE HYDROGEN-OXYGEN FUEL CELL

  • spacecraft
  • 2H2 + 4OH- -> 4H2O + 4e-
  • O2 + 2H2O + 4e- -> 4OH-
  • OVERALL: 2H2 + O2 -> 2H2O
• EVALUATION OF NON-RECHARGEABLE CELLS?

  + cheap

  -waste issues
• EVALUATION OF RECHARGEABLE CELLS?

  + less waste

  + cheaper long-term

  + lower environmental impact

  -some waste issues (after usage)
• EVALUATION OF HYDROGEN-OXYGEN FUEL CELLS?

  + only waste is water

  + do not need recharging

  + very efficient

  -constant fuel supply required

  -hydrogen is flammable and expensive

  -hydrogen made using fossil fuels

  -high cost