A step towards new ‘beyond lithium’ rechargeable batteries with superior performance has been made by researchers at the University of Bath in the UK.
Rechargeable batteries are already used for wide range of applications, from powering mobile phones and electric cars to electrical grid storage. At present, these applications are mostly met by lithium-ion batteries. But as we continue to transition from fossil fuels to low emission energy sources, new battery technologies will be needed for new applications and more efficient energy storage.
"Multivalent batteries are a really exciting direction for battery technology, potentially offering higher charge densities and better performance. New battery technologies are going to be more and more important as we wean ourselves off fossil fuels and adopt greener energy sources."Benjamin Morgan, University of Bath
One approach to developing batteries that store more energy is to use ‘multivalent’ metals instead of lithium. In lithium-ion batteries, charging and discharging transfers lithium ions inside the battery. For every lithium ion transferred, one electron is also transferred, producing electric current. In multivalent batteries, lithium would be replaced by a different metal that transfers more than one electron per ion. For batteries of equal size, this would give multivalent batteries better energy storage capacity and performance.
The Bath researchers, together with colleagues from France, Germany, Holland and the US, have now shown that titanium dioxide can be modified to allow it to be used as an electrode in multivalent batteries, providing a valuable proof of concept in their development. These modifications comprised deliberately introducing defects in titanium dioxide to form high concentrations of microscopic holes. The researchers then showed that these holes can be reversibly occupied by magnesium and aluminum, which carry more than one electron per ion.
The team also described a new chemical strategy for designing materials that can be used in future multivalent batteries. They report their findings in a paper in Nature Materials.
"Multivalent batteries are a really exciting direction for battery technology, potentially offering higher charge densities and better performance," said Benjamin Morgan in the Department of Chemistry at the University of Bath. "New battery technologies are going to be more and more important as we wean ourselves off fossil fuels and adopt greener energy sources."
"There are quite a few technical hurdles to overcome, including finding materials that are good electrodes for multivalent ions. We've shown a way to modify titanium dioxide to turn it into a multivalent electrode.
"In the long term, this proof of concept is a possible step towards ‘beyond lithium’ batteries with superior performance."
This story is adapted from material from the University of Bath, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.