Conducting Block Copolymer Binders for Carbon-Free Hybrid Vanadium Pentoxide Cathodes with Enhanced Performance.
Polymeric binders are essential to battery electrodes, mechanically stabilizing the active materials. Most often, these binders are insulating, and conductive carbons must be added to the electrode structure. Conductive polymer binders, those that transport both ions and electrons, are of primary interest because they potentially eliminate the need for carbon additives. However, it is challenging to incorporate both ion- and electron-conductive polymeric binders into electrode systems because of differences in physical affinities among the two polymer types and the electroactive material. Here, we investigate amphiphilic polymeric binders comprised of electron- and ion-conducting poly(3-hexylthiophene)-block-poly(ethylene oxide) (P3HT-b-PEO) as compared to P3HT, PEO, and a blend of P3HT/PEO homopolymers in carbon-free V2O5cathodes. The electrode with P3HT-b-PEO binder has the highest capacity of 190 mAh/g, whereas V2O5is only 77 mAh/g at a C rate of 0.1 after over 200 cycles: a 2.5-fold improvement. Similarly P3HT, PEO, and the blend have capacities of 139, 130, and 70 mAh/g, which are not nearly as impressive as the block copolymer binder. The unique architecture of P3HT-b-PEO, wherein P3HT and PEO blocks are covalently bonded, promotes the uniform distribution of conductive binders within the V2O5structure, whereas the analogous P3HT/PEO blend suffers from phase separation. This work demonstrates that conductive block copolymer binders enable carbon-free electrodes for lithium-ion battery systems.
Artie McFerrin Department of Chemical Engineering, Texas A&M University , College Station, Texas 77843, United States.
Hyosung
H
An
Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States.
Xiaoyi
X
Li
Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States.
Cody
C
Chalker
Artie McFerrin Department of Chemical Engineering, Texas A&M University , College Station, Texas 77843, United States.
Maria
M
Stracke
Department of Chemical and Biomolecular Engineering, Rice University , Houston, Texas 77005, United States.|Department of Materials Science and NanoEngineering, Rice University , Houston, Texas 77005, United States.
Rafael
R
Verduzco
Artie McFerrin Department of Chemical Engineering, Texas A&M University , College Station, Texas 77843, United States.|Department of Materials Science and Engineering, Texas A&M University , College Station, Texas 77843, United States.
Jodie L
JL
Lutkenhaus
block copolymer; conductive binders; electroactive polymers; hybrid electrodes; lithium-ion battery; poly(3-hexyl thiophene); poly(ethylene oxide); vanadium pentoxide