Storage of energy through electrochemical means (batteries, capacitors) is critical to providing power for advanced transportation and portable electronics. Next-generation energy storage materials must simultaneously satisfy a number of criteria: excellent charge and ion transport, high capacity, and reversible charge transfer. For this reason, electron- and ion-conducting polymers are often explored as additives in cathodes such as V2O5, LiCoO2, LiFePO4, etc. to form hybrid electrodes. Unfortunately, it remains extremely difficult to obtain a hybrid electrode that successfully balances electron and ion transport with charge transfer because of large-scale phase separation and poor structure control among the electrode?s various components.
This project will investigate a model system of hybrid electrodes for energy storage based on nanostructured blends of poly(3-alkylthiophene)-block-poly(ethylene oxide) (P3AT-b-PEO) multifunctional block copolymers and V2O5. P3AT-b-PEO is capable of simultaneous electron and ion transport, and V2O5 is a commonly explored high-capacity cathode material for Li-ion batteries. V2O5 will be synthesized within selected polymer blocks using ?structure directed? synthesis. The PIs hypothesize that through bottom- up assembly methods, the resulting hybrid materials will exhibit favorable properties characteristic of both organic and inorganic components.
This project will determine the relationship between block copolymer composition and morphology as it is affected by V2O5, side chain functionalization, and electrochemical performance. The relationship between block copolymer morphology and charge transfer, electron transport, and ion transport has never before been systematically investigated as a whole, so the proposed research will establish a broad knowledge base to guide the development of multifunctional block copolymers for energy storage. First, the PIs will establish relationships between the morphology of hybrid electrodes containing block copolymer bearing a single type of side chain and V2O5 and electrochemical performance (Objectives 1 and 2). This knowledge will then be applied to a wider family of block copolymers of varying side chain chemistry so as to balance electrochemical properties with processability.
The proposed work will have broader impacts within the scientific community as well as the general public through educational activities and outreach. Within the scientific community, this work will establish a knowledge base for multifunctional block copolymers in electrodes, where several processes (reaction and diffusion) must be balanced.
The PIs will pursue educational activities including hosting high school teacher(s) through Enrichment Experiences in Engineering, providing summer research opportunities for talented, underrepresented groups from the Houston Community College system, hosting Nova-sponsored, materials science-themed Science Cafés at Houston-area high schools, and organizing Texas Soft Matter Meetings at TAMU and Rice University.
