Batteries and fuel cells – simple, rechargeable and fuel cells
ChemistryElectrochemistryAges 17–18
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Sign in to playFour screens on chemical cells. Simple cells: pick two metals, read the voltage from the difference in standard electrode potentials, join cells in series to light an LED and record a results table. Fuel cells: hydrogen–oxygen (acid or alkaline electrolyte) and methanol, with half-equations, a voltage–current density curve and efficiency compared with a petrol engine. Rechargeable cells: a lead–acid and a lithium-ion cell discharge (galvanic cell) and recharge (electrolysis), compared with a non-rechargeable alkaline cell. Compare: specific energy, voltage, cycle life, advantages and disadvantages.
Lesson: Chemical cells and batteries, fuel cells, lead–acid and lithium-ion rechargeable cells
What it shows
A cell turns the energy of a redox reaction into electrical energy. In a simple cell the more reactive metal is the negative electrode, and the further apart the two metals are in the reactivity series, the larger the voltage; cells joined in series add their voltages. A fuel cell is supplied continuously with fuel and oxygen, so it never needs recharging, and it can turn more of the fuel's energy into electricity than an engine that burns it. In a rechargeable cell the discharge reaction can be reversed by electrolysis, which is not possible in an alkaline cell.
How to use
On Simple cells, choose Metal A and Metal B, then increase Cells in series until the LED lights; press Record to build the table and tick Reverse one cell to see what happens. On Fuel cells, change Fuel cell type and Current density and watch the voltage and efficiency bars. On Rechargeable cells, press Discharge, then Charge, and compare the energy out and in. Use Compare for the evaluation.
Parameters you can change
- Screen Simple cells, Fuel cells, Rechargeable cells, Compare
- Metal A Mg, Al, Zn, Fe, Ni, Sn, Pb, Cu, Ag
- Metal B Mg, Al, Zn, Fe, Ni, Sn, Pb, Cu, Ag
- Cells in series 1–6
- Fuel cell type Hydrogen–oxygen, acid electrolyte, Hydrogen–oxygen, alkaline electrolyte, Direct methanol
- Current density 0–1 A/cm²
- Cell type Lead–acid, Lithium-ion, Alkaline (not rechargeable)
- Charge / discharge current 0.1–1 C
Questions to explore
- Which pair of metals gives the largest voltage, and how can you predict it from the reactivity series?
- Why does a hydrogen fuel cell give less than 1.23 V when a large current is drawn?
- Why can a lead–acid cell be recharged but an alkaline cell cannot?
