Development of energy storage systems that can be used to study principles of supercapacitors, fuel cells,
and batteries. Pupils can assemble the energy source and use it to drive a model car, for example.

A homemade aluminum-air battery
A nice scientific experiment, maybe it is the future energy source of all vehicles.
2 carbon cathodes 14 Eur
Consist of nanoporous carbon press-glued onto a special alloy metal mesh. 4.4 x 7 cm active area (fits into Tic-Tac 49g box). Suitable for a DIY aluminum-air (or other metal-air) battery experiment with 10% NaOH electrolyte (sewage cleaning liquid). Gives maximum >1 W power for racing with a model car. Are reuseable after washing with water.
Shipping cost to USA (6-9 days) ~9 Eur, to Europe (2-7 days) ~8 Eur.
Courier (1-3 days) 60-120 Eur.
contact: (specify product, nr of items, delivery address, phone nr)

NEW! This is more advanced cathode that has constant high power during long-lasting experiments.
It also works with NaCl solution. Mg-air or salt-water battery is the safest for schools.
Gas-diffusion cathode Ask price
This cathode is non-permeable to water, but lets oxygen in to react. Can be used in neutral or basic solutions, has long lifetime in hydroxide solution. Active area is 4.4 x 7 cm (fits into Tic-Tac 49g box). Suitable for an aluminum-, magnesium, or zinc-air battery as well as alkaline fuel cell cathode. It is much more powerful than the carbon cathode. Are reuseable after washing with water.
Current output is up to 1 A/cm2 in air or 2 A/cm2 in oxygen at 50 oC.

High purity metals and alloys
High purity aluminum has higher voltage and lower corrosion in hydroxide solution than low purity Al (such as kitchen foil). Zinc-air batteries are technically rechargeable and zinc has very low corrosion in hydroxide. Magnesium-air batteries work best with neutral NaCl electrolyte. All packs contain 2 100x44 mm electrodes, which fit into a Tic-Tac 49g box. Suitable for a metal-air fuel cell with the carbon cathodes and NaCl or hydroxide electrolyte (sewage cleaning liquid).
Aluminum (Al) 99.6% 0.2 mm thick 2 Eur
Zinc (Zn) 99.9% 0.2 mm thick 6 Eur
Magnesium (Mg) 99.8% 1 mm thick 6 Eur
Mg alloy AZ31B 1 mm thick 9 Eur
(~95% Mg, ~3% Al, ~1% Zn, ~0.5% Mn)
Copper (Cu) 99.9% 1 mm thick 9 Eur
(for Zn-Cu battery or for lemon battery)

Higher purity:
Al 99.99% 0.2 mm thick 8 Eur
Mg 99.99% 0.1 mm thick 17 Eur

Ask for other metal foil sizes

Related stuff for batteries and electrolysis

Vessel for the metal-air battery 2 Eur

6 mL syringe with plastic needle 2 Eur
(To fill the metal-air battery with electrolyte)

Step-up voltage converter (>0.8 V to USB) 8 Eur
(Can be used to charge a mobile phone using a single metal-air battery element, max 5 V 600 mA)

Graphite rod 8 cm diameter 25 cm length 8 Eur
(Suitable for electrolysis or electrodeposition experiments.)

DIY model car parts
(special micro motor, gear, 4 wheels, shafts, cell, wires, crocodile clips, DIY body. Designed for racing with the single metal-air battery element)

Gallium (Ga) 99.99% 10 g 14 Eur
(Ga + Al reacts with water, producing hydrogen. And it melts in hand.)

A homemade microbial fuel cell
Free energy from wastewater. Power is a few mW, but fuel is something you pay to get rid of.
Great scientific project at home or school.
Also ask for the whole kit including vessel.

Two electrodes for a microbial fuel cell 17 Eur.

Anode and cathode having diameter of 7.6 cm and 8 cm, respectively. Suitable for a DIY microbial fuel cell, just find a vessel and some fuel (wastewater, mud, waste food). Anode is packed airtightly, oxygen removed. Instructions are here.

A homemade supercapacitor
A full kit containing everything to make a supercapacitor at home is under development. Scientific project at home or school to study electric energy storage.
Supercapacitor kit - coming soon.