MULTI-FUNCTIONAL POLYPEPTIDES FOR APPLICATIONS IN LITHIUM ION BATTERIES

dc.contributor.advisorAllen, Mark A
dc.contributor.authorWinton, Alexander James
dc.contributor.departmentChemistry & Biochemistry
dc.contributor.programChemistry
dc.date.accessioned2021-01-29T18:12:59Z
dc.date.available2021-01-29T18:12:59Z
dc.date.issued2019-01-01
dc.description.abstractBiological organisms have demonstrated the ability to synthesize complex inorganic structures through evolved polypeptides (nature's most diverse polymer). The investigation of these polypeptides has led to improved understanding of biomineralization processes and generated interest in biomimetic, non-natural materials, for applications in sensing or energy storage. Lithium ion (Li+) batteries represent one such material of interest due to their ubiquity as a portable energy device. While highly developed, current Li+ technology still faces limitations in cost, safety, cycle life, and power performance hindering its applications in future higher power systems. This research seeks to utilize a bio-inspired approach for addressing limitations in Li+ batteries by employing a bio-tethering polypeptide as a specific electrode binding agent. Initially, a versatile bacterial expression scheme was developed for generation of polypeptides identified through combinatorial display. A desired target peptide was expressed with an N-terminal 6xHis-SUMO tag and subsequently purified by ULP1 cleavage. Expression of 12mer and 24mer domains has resulted in yields of 8 – 13 mg/L of purified peptide which were then utilized for further study. M13 bacteriophage display was carried out against electrode materials utilized in Li+ batteries and mutant phage exhibiting binding for Li4Ti5O12 (LTO) and MWCNTs were identified. Phage affinity for LTO was assessed through binding assays and a peptide (THHSTKYWPPSQ) was selected for further characterization by isothermal titration calorimetry (ITC) where it demonstrated micromolar affinity for LTO. Alanine scanning and subsequent ITC experiments indicated three residues pertinent for the peptides' affinity. A bifunctional peptide composed of the characterized LTO peptide and an MWCNT peptide was expressed in bacteria and purified. The bifunctional peptide exhibited similar LTO affinity in ITC experiments. Incubation of the bifunctional peptide with MWCNTs in aqueous solution demonstrated its ability to interact with MWCNTs by enhancing their dispersion. This bifunctional peptide was utilized as a specific binding agent in LTO electrode slurries which were processed in aqueous rather than organic solvent. An optimized peptide electrode exhibited improved capacities at fast charge-discharge rates compared to a standard LTO electrode indicating the ability for a bifunctional peptide to be utilized as a specific binding agent in lithium ion battery electrodes.
dc.formatapplication:pdf
dc.genredissertations
dc.identifierdoi:10.13016/m2zxty-rtwj
dc.identifier.other11975
dc.identifier.urihttp://hdl.handle.net/11603/20784
dc.languageen
dc.relation.isAvailableAtThe University of Maryland, Baltimore County (UMBC)
dc.relation.ispartofUMBC Chemistry & Biochemistry Department Collection
dc.relation.ispartofUMBC Theses and Dissertations Collection
dc.relation.ispartofUMBC Graduate School Collection
dc.relation.ispartofUMBC Student Collection
dc.sourceOriginal File Name: Winton_umbc_0434D_11975.pdf
dc.subjectbio-tethering
dc.subjectgenetically engineered polypeptides for inorganics
dc.subjectlithium ion
dc.subjectmulti-functional peptide
dc.subjectpeptide expression
dc.subjectPhage display
dc.titleMULTI-FUNCTIONAL POLYPEPTIDES FOR APPLICATIONS IN LITHIUM ION BATTERIES
dc.typeText
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