Protein Batteries For An Environment-Friendly And Safer Energy Storage
Proteins are good for building muscle as we all know, but their building blocks also might be helpful for building sustainable organic batteries called protein batteries which could someday be an effective and viable substitute for conventional lithium-ion batteries, without their safety and environmental concerns. By using synthetic polypeptides — that make up protein — and other polymers, scientists have taken the initial steps toward constructing electrodes for such power sources. This work can also provide a new understanding of electron-transfer mechanisms.
The scientists will present their results today at the American Chemical Society (ACS) Fall 2019 National Meeting & Exposition.
Tan Nguyen who is a Ph.D. student who helped develop the project said that the current trend in the battery field is to look at how the electrons are transported within a polymer network. The real beauty of polypeptides is that we can control the chemistry on their side chains in 3D without changing the geometry of its backbone, or say the main part of the structure. We can then systematically examine the effect of changing different aspects of the side chains.
Lithium-ion batteries used currently can harm the environment
, and because the cost of recycling them is higher than manufacturing these from scratch and they often accumulate in landfills. Currently, there is no safe way of disposing of the lithium batteries. By developing a protein-based, or organic, the battery would change this scenario.Karen Wooley who leads the research team at Texas A&M University, said that the amide bond along the peptide backbone is pretty stable — which ensures that the durability is there, and we can then trigger when these break down for recycling. Wooley envisions that polypeptides could eventually be used in applications such as flow batteries for storing electrical energy. She added that the other advantage of using protein batteries is this protein like architecture, we are building in the kinds of conformations that are found in proteins in nature that already transport electrons efficiently and we can also optimize this to control battery performance of these protein batteries.
The scientists built the system using electrodes made of composites of carbon black, constructing the polypeptides that contain either viologen or 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO). Scientists attached viologens to the matrix used for the anode (negative electrode) and used a TEMPO-containing polypeptide for the cathode (positive electrode). The viologens and TEMPO are redox-active molecules. Nguyen said that what they have measured so far for the range, the potential window between the 2 materials is about 1.5 volts, suitable for low energy requirement applications, such as biosensors.
Nguyen has synthesized several polymers, which can adopt different conformations like the random coil, an alpha helix, as well as a beta-sheet to investigate their electrochemical characteristics, for potential use in an organic battery. With these peptides in hand, Nguyen is collaborating with Alexandra Danielle Easley who is a Ph.D. student in Jodie Lutkenhaus’s lab at Texas A&M University to build the protein batteries and its prototypes. Part of this work will include testing to better understand how the polymers function when they’re organized on a substrate.
While this early-stage study has far to go before organic-based protein batteries are commercially available, the flexibility and its variety of structures that proteins can provide promises a wide potential for sustainable energy storage that is very environment-friendly.
