Tuning Ion Conducting Pathways Using Holographic Polymerization

Drexel University, Philadelphia PA

Investigators

Abstract

Lithium-ion batteries are the systems of choice for portable electronic devices because they offer high-energy density, flexible and lightweight design and long lifespan. If lithium metal is used to form lithium-metal battery, even higher power densities can be achieved. However, the system proved to be not viable, because the liquid electrolytes currently used can lead to explosion hazards. In order to achieve safe operation for lithium-metal battery, mechanically strong polymer electrolyte membranes or PEMs with good room temperature ionic conductivity are needed. This grant provides funding for development of a novel nanomanufacturing process, i.e. holographic polymerization, to fabricate such membranes. Holographic polymerization employs multiple light beams and photosensitive material mixtures to create functional nanostructures. Under this grant, a series of polymer electrolyte membranes with precise structural control will be fabricated using this technique. Specifically, electrolytes will form tiny channels with the size of approximately a millionth of the diameter of a human hair. Such channels will significantly improve the efficiency of ion conduction in these membranes, while they retain their strength. The project will lead to a library of unprecedented polymer electrolyte membranes that enable safe operation of lithium-metal batteries. The proposed system is advantageous because extremely regular, tiny ion conducting channels can be formed in a controllable fashion in these membranes. Therefore, the proposed approach provides a promising solution to achieving both enhanced mechanical and ionic conducting properties of PEMs, a major challenge for using such materials in lithium batteries. There are also numerous material choices in the proposed system to meet different battery needs. Furthermore, the fabrication process takes approximately 30 seconds, and it can potentially be combined with continuous, roll-to-roll nanomanufacturing for scale-up purposes.