Enhanced aluminium batteries could provide 'perfect' renewable energy storage

Aluminium batteries enhanced with cheap and abundant materials could provide the perfect low-cost storage for renewable energy, researchers have claimed.

While lightweight lithium-ion batteries are ideal for electric cars, they are also quite expensive – and therefore unsuitable for large-scale, stationary power storage, claimed scientists from ETH Zurich and Empa in Switzerland.

Instead, the team identified two new materials that could improve cheap aluminium batteries. The first was titanium nitride, a corrosion-resistant ceramic material.

The electrolyte fluid in aluminium batteries is extremely aggressive and corrosive, even damaging gold and platinum, so the team searched for a hardy replacement. Lead researcher Maksym Kovalenko and colleagues said they found what they were looking for with titanium nitride, an easy-to-manufacture compound made of abundant titanium and nitrogen.

The scientists made batteries with conductive parts made of titanium nitride in the laboratory. The material can form thin films, coat other materials or even be printed on to plastic for greater flexibility.

The second identified material was polypyrene, which could act as the positive electrode in a new generation of low-cost aluminium batteries. While the negative electrodes are made of aluminium, the positive pole is usually graphite, a mineral which is resistant to modification.

Instead, the team used polypyrene, which rivals graphite in energy storage. Properties such as porosity can also be adapted, the researchers said, meaning it can be optimised for specific applications.