These 'mollusks-inspired' batteries promise better performance

Snails have inspired scientists to develop new high performance Li-ion battery electrodes.

According to new research presented at the 59th annual meeting of the Biophysical Society, researchers at the University of Maryland, Baltimore County (UMBC) have isolated a peptide, a type of biological molecule, which binds strongly to lithium manganese nickel oxide (LMNO), a material that can be used to make the cathode in high performance batteries. The peptide can latch onto nanosized particles of LMNO and connect them to conductive components of a battery electrode, improving the potential power and stability of the electrode.

Barannikova said that one of the inspirations for her research was the way that organisms such as mollusks use peptides to control the growth of their shells. They demonstrate remarkable control in order to build intricate nano- and macrostructures from inorganic materials like calcium carbonate.

The researchers borrowed the general approach of the mollusks, but had to employ some lab-bench wizardry to find the appropriate peptide. No snail, after all, makes its shell from lithium manganese nickel oxide.

Barannikova and her colleagues used a procedure called "Phage Display" to screen more than one billion possible peptides in search of one that would stick strongly to lithium manganese nickel oxide. They isolated a peptide that binds to lithium manganese nickel oxide by combining the library with a sample of the metal oxide and then repeatedly washing away the peptides that didn't stick to it. They then combined the newly-discovered peptide with a previously isolated peptide that binds to carbon nanotubes. Carbon nanotubes can serve as conductive nanowires in Li-ion electrodes.

The resulting peptide could then form a bridge, binding to both the lithium manganese nickel oxide nanoparticles and the carbon nanotubes and keeping them close to each other so that they can maintain a connection through multiple charging cycles. By helping to maintain a highly organized architecture at the nanoscale, the researchers expect that their peptides will improve the power and cycling stability of future Li-ion batteries, allowing them to be smaller and maintain longer lifetimes.

The researchers will present their results at the 59th annual meeting of the Biophysical Society.