Fuji Pigment Unveils Aluminium-Air Battery Rechargeable by Refilling Salty or Normal Water

Fuji Pigment Co. Ltd. has developed a new type of aluminium-air battery rechargeable by refilling salty or normal water and having a modified structure that ensures longer battery lifetime.

Due to fossil fuel depletion and the air pollution arising from its combustion, there is urgent demand for renewable, clean fuel alternatives for our future energy supply. Although commercialized rechargeable lithium-ion batteries are widely used in mobile phones, laptop computers, and similar electronic devices, their energy density is still insufficient to permit their use in electric vehicles at an industrial level with economical cost. The highest energy storage technologies faced by recent researchers are the metal-air batteries. Several metal-air batteries such as lithium, iron, aluminium, magnesium and zinc-air, etc. have been investigated due to their promising energy densities. Among them, aluminium is an abundant, attractive anode material for energy storage and conversion because of its high specific capacity, highly negative standard electrode potential. In addition, aluminium is the most recycled metal in the world and is economically cheap.

The aluminum-air battery has a theoretical specific energy level of 8,100 Wh/kg and has the second largest capacity among various types of potential secondary batteries. Theoretical specific energy of a commercialized lithium-ion battery is 120-200 Wh/kg. Therefore, the aluminium-air battery possesses theoretical capacity more than 40 times as large as that of a lithium-ion battery.

A major barrier to commercialization has been the high corrosion rate of aluminium during the electrochemical process. In addition, byproducts such as Al2O3 and Al(OH)3 accumulate at electrodes, hindering further battery reaction.

Regarding this obstacle, Dr. Ryohei Mori at Fuji Pigment Co. Ltd. (headquartered in Kawanishi, Hyogo Prefecture, Japan; http://www.fuji-pigment.co.jp/en/index.html) has invented the new type of aluminium-air battery. He has modified the aluminium-air battery structure by placing ceramic and carbonaceous materials between aqueous electrolyte and electrodes as an internal layer. Owing to this modified structure, anode corrosion and byproduct accumulation were suppressed, which resulted in longer battery lifetime.

The newly invented aluminium-air battery can work just by refilling salty water or normal water once in a while.

Aluminium is an abundant, cheap and safe material which can be applied for metal-air batteries. Therefore, battery prices can be cheap.

The new battery can be manufactured and work in an ambient atmosphere because it is stable in ambient air conditions. Moreover, there is no need to worry about explosion or flammability like a lithium-ion battery.

All materials (electrode, electrolyte) are safe and cheap, and can be made very easily even in the house kitchen.

Theoretically, the aluminium-air battery has the second largest capacity next to a lithium-air battery which is the strongest secondary battery. (lithium-ion battery: 120-200 Wh/kg, aluminium-air battery: 8,100Wh/kg, lithium-air battery: 11,400 Wh/kg)

The aluminium-air battery has theoretical capacity more than 40 times that of a lithium-ion battery.