chem batteries

equation for batteries to memorize

lead acid battery (discharging)

A: Pb(s) +HSO4-(aq)—→ PbSO4 +H+2e

C: PbO2(s) +3H +HSO4-(aq)+ 2e—→ PbSO4(s) +2H2O(l)

Overall: Pb(s) + PbO2(s) +2H2SO4(aq)—→ 2PbSO4(s) +2H2O(l)

lead acid batter (recharging)

A: PbSO4(s)+2H2O(l)—-. PbO2(s) +3H+ HSO4-(aq)+ 2e

C: PbSO4(s) + H+ 2e—→ Pb(s) + HSO4-(aq)

overall: 2PbSO4(s) +2H2O(l)—→ Pb(s) +PbO2(s) +2H2SO4(aq)

Nickel-cadimium battery (discharging)

A: Cd(s) + 2OH-(aq)—→ Cd(OH)2(s) + 2e

C: 2NiO(OH)(s) +2H2O(l)+ 2e—→ 2Ni(OH)2(s) +2OH-(l)

Overall: Cd(s)+2NiO(OH)(s) +2H2O(l)—→ 2Ni(OH)2(s)+Cd(OH)2(s)

Nickel-cadmium battery(recharging)

A: 2Ni(OH)2(s) +2OH-(l)—→ 2NiO(OH)(s) +2H2O(l)+ 2e

C: Cd(OH)2(s) + 2e—→ Cd(s) + 2OH-(aq)

Overall: 2Ni(OH)2(s)+Cd(OH)2(s)—→ Cd(s)+2NiO(OH)(s) +2H2O(l)

lithium-ion battery(discharging)

A: Li(graphite)—→ Li+(electrolyte) +e

C: Li(electrolyte) +e+CoO2(s)—→ LiCoO2(s)

Overall: Li(s)+CoO2(s)—→ LiCoO2(s)

Lithium-ion battery (recharging)

A: LiCoO2(s)—→ Li(electrolyte) +e+CoO2(s)

C: Li+(electrolyte) +e—→ Li(graphite)

overall: LiCoO2(s)—→ Overall: Li(s)+CoO2(s)

hydrogen fuel cells

1. alkali fuel cell

2. acidic fuel cell

3. PEM fuel cell

alkali fuel cell

A: 2H2(g)+4OH-(aq)—→ 4H2O(l)+4e

C: 2H2O(l) +O2(g) +4e—→ 4OH-(aq)

overall: 2H2(g)+O2(g)—→ 2H2O(l)

acidic fuel cell

A: 2H2(g)—→ 4H+(aq) +4e

C: O2(g) +4H+(aq) +4e—→ 2H2O(l)

overall: 2H2(g)+O2(g)—→ 2H2O(l)

PEM fuel cell

A: 2H2(g)—→ 4H+(aq) +4e

C: O2(g) +4H+(aq) +4e—→ 2H2O(l)

overall: 2H2(g)+O2(g)—→ 2H2O(l)

Methanol fuel cell

1. direct methanol fuel cell

   a. PEM/acidic electrolyte

   b. Alkaline electrolyte

2. Reformed methanol fuel cell

PEM/acidic electrolyte

A: CH3OH(aq)+ H2O(l)—→ CO2(g) +6H+(aq) +6e

C: 3/2 O2(g)+6H+(aq)+ 6e—→ 3H2O(l)

overall: CH3OH(aq)+3/2 O2(g)—→CO2(g)+ 2H2O(l)

Alkaline electrolyte

A: CH3OH(aq)+ 6OH-(aq)—→ CO2(g)+5H2O(l) +6e

C: 3/2 O2(g)+ 3H2O(l) +6e—→ 6OH-(aq)

overall: CH3OH(aq)+3/2 O2(g)—→CO2(g)+ 2H2O(l)

reformed methanol fuel cell

A: 2H2(g)—→ 4H+(aq) +4e

C: O2(g) +4H+(aq) +4e—→ 2H2O(l)

overall: 2H2(g)+ O2(g)—→ 2H2O(l)