Conducting Polymer Coated Cathode Nanoparticles for Improved Battery Performance

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This grant supports research to enhance lithium ion battery performance and longevity through research on a unique manufacturing process that generates new scientific knowledge. Currently, lithium ion battery electrode materials are prone to degrade when the battery is repeatedly used and recharged. Specifically, cathode materials degrade in the highly energetic, corrosive battery environment. To overcome these challenges and to make the cathode materials more stable, a novel manufacturing process is used to wrap a protective conducting polymer layer around the nanoparticles that make up the cathode. This process creates an extremely thin film that helps keep the underlying cathode nanoparticles active. The electrically conducting polymer maintains a well-connected battery circuit and provides a physically dense and chemically stable barrier for maximum protection. This project studies the oxidative chemical vapor deposition process to manufacture protected cathode materials for more stable, high performance batteries. The ability to coat miniscule parts and components with ultrathin conducting polymers impacts broader energy technology areas such as solar cells, fuel cells and supercapacitors, which creates a more sustainable U.S. energy economy. Furthermore, this coating technology enables applications in sensors, electronics, smart textiles, biomedical and aerospace industries that makes U.S. manufacturing more competitive. This research involves disciplines of manufacturing, materials science, electrochemistry and nanotechnology that attracts broad participation, particularly from underrepresented groups and women, and helps equip the future U.S. workforce with cutting-edge science and value-added skill-sets.The oxidative chemical vapor deposition (oCVD) process is a solvent-free thin film coating technique that directly polymerizes the monomer vapor into a solid intrinsically conducting polymer (ICP) film through the use of an oxidant vapor. Being liquid-free, it overcomes conventional solvent processing problems of encapsulating conducting polymer coatings around cathode nanoparticles. Conducting polymers are often not very soluble so they are not amenable to solution processing. Furthermore, liquid methods are often less precise, which makes it difficult to produce ultrathin, nanoscale coatings. The dry oCVD process shows promise in overcoming these manufacturing barriers. However, this technology is relatively new, and this research fills the knowledge gap by identifying the key processing factors and mechanisms for achieving conformal, fully encapsulating ICP coatings around particle substrates. The research further understands the precise role of the coatings in stabilizing cathode materials and enhancing battery performance. The research team conducts a comprehensive experimental analysis from materials fabrication to device testing to understand the relevant processing-structure-property relationships for achieving maximum cathode protection and superior battery performance.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.