Polypeptides for Bio-Tethering and Self-Assembly of Lithium Ion Battery Electrodes

Abstract

The goal of this research is to isolate multifunctional polypeptide sequences for bio-tethering electrode material and carbon nanotubes in order to decrease internal resistance in lithium ion batteries thereby improving their performance. Phage display is the key technique performed in our research. This involves the use of an M13 bacteriophage library which has been genetically engineered to express a randomized polypeptide sequence of 12 amino acids on the pIII minor coat protein. To perform phage display a library of bacteriophage expressing these randomized polypeptide sequences were mixed with electroactive materials lithium manganese oxide(LMO) and lithium titanate oxide(LTO). Samples were then shaken and elution of bound phage was performed by adding increasing concentrations of surfactant in order to isolate phage that stick tightly to the electroactive materials. The supernatants from each of the successive wash rounds were saved and titered. The strongest elutions represent bacteriophage expressing a peptide sequence with high binding affinity for the tested materials. Isolated colonies produced from single bacteriophage were then sequenced. Results have currently been obtained for LTO and LMO binding peptides. As research progresses we will refine and isolate other peptides that bind specifically to electroactive materials as well as conductive carbon nanotubes, current collectors, and separator materials. Binding studies will be performed to characterize the amino acid sequence as well as to improve peptide-material interactions, such that electrode binders may be replaced by these peptides. These peptides will then be used to generate an aqueous, self-assembling, lithium ion battery electrode.This work was funded by the UMBC Department of Chemistry and Biochemistry.