Christopher Li, PhD, professor of materials science and engineering, has received back-to-back NSF grants to support fundamental understanding of solid-state battery functioning and the development of nanoparticle-polymer superstructures.
Patterned Solid Polymer Electrolytes for Solid-State Batteries
Lithium batteries have become the energy source of choice for a vast array of electronics because of their long life, high charge density and light weight. One of the major drawbacks of lithium batteries is their tendency to develop dendrites – spiky crystal structures that spring up like weeds during charging, causing short-circuits and posing a serious safety hazard. Solid-state batteries, which use a solid electrolyte, rather than liquid or gel, to serve as the battery’s conductive pathway, have shown great promise in increasing performance and reducing the safety hazards of lithium batteries.
Significant efforts devoted to solid-state battery research have resulted in impressive performance improvement over past two decades, however fundamental understanding of metal nucleation, growth and interaction with solid electrolytes remains elusive.
Li has received a three-year NSF grant for research that aims to bridge this knowledge gap by establishing a new solid polymer electrolyte (SPE) system to decouple complex factors such as local mechanical, chemical and electrochemical effects on lithium and sodium electrodeposition.
These novel SPEs are designed to have micro-size features that can be used to understand the battery charging and discharging processes. This class of unique pSPEs is anticipated to allow for a detailed mechanistic study of metal nucleation and growth at the electrode/electrolyte interface.
The SPEs will serve as a new materials platform to investigate metal electrodeposition, and they will significantly improve fundamental understanding of the complex electrode/electrolyte interface in solid-state batteries. The knowledge gained from this project will benefit the next generation of battery design and pave the way for safer and more efficient energy storage solutions.
Co-crystallization Assembly of Nanoparticles and Polymers
Nanoparticles ranging from one to a hundred nanometers are some of the most important building blocks for advanced functional materials and have demonstrated intriguing optical, electronic, and mechanical properties.
NSF has awarded Li a three-year research grant for a project that aims to fabricate ordered nanoparticle-polymer superstructures by co-crystallizing linear crystalline polymers and inorganic nanoparticles. This collaborative project will be conducted in conjunction with researchers from The University of Tennessee at Knoxville.
Polymers are soft and flexible, while inorganic nanoparticles are stiff and rigid. They are unlikely to co-exist in a regular crystalline structure. However, recent work shows that they co-crystallize into unusual structures, such as hollow spheres, by controlling the chemistry and crystallization conditions.
This project will systematically investigate how to fabricate and control these novel co-assembled structures. It is anticipated that a library of unprecedented nanoparticle-polymer superstructures will be formed, and these structures could find applications in bioimaging and drug delivery.