Triple-functional carbon molecular sieve separators for next-generation Li-S batteries
Abstract
Approved for public releaseTriple-functional carbon molecular sieve separators for next-generation Li-S batteriesGlobal energy demand is rising, which is driving the need for sustainable energy storage solutions alongside renewable energy growth. Lithium-ion batteries (LIBs) are widely used, but lithium metal batteries (LMBs) offer higher energy density. Within the class of LMBs, the lithium-sulfur (Li-S) battery presents a promising alternative to current LIBs, offering higher specific energy, lower cost, and reduced CO2footprint. However, they face challenges that include unstable lithium anodes and polysulfide crossover. Extensive research has focused on cathode and battery separator improvements, particularly through the use of carbon-based coatings. These coatings prevent the loss of active material and damage to the anode by confining polysulfides, which are harmful to battery performance. The construction of microporous carbon layers on battery separators has shown promise in containing polysulfides and providing reaction sites fortheir further reduction and utilization. However, cross-flow contamination and rapid capacity decay at low cycling rates remain challenges. To mitigate these, excess lithium is often used, but this reduces battery performance. Solutions include modifying the solid electrolyte interphase (SEI) and using protective coatings like polymers. Nanoporous polymer coatings offer processability and functionality but require careful selection and functionalization. Carbon molecular sieves (CMS) are specialized filters made from tinycarbon structures. These materials have the unique ability to selectively trap or even reject certain molecules while letting others pass through. This ability can be tuned by changing how the CMS materials are made. From the perspective of an Li-S battery, the multifunctional properties of CMS are very interesting for use as a separator and as a cathode. CMS can solve the issues of stoppingthe transport of small sulfur compounds in the battery while still promoting electrical conductivity. If successful, CMS materialscan address the usual problem of trading off between addressing one performance challenge while reducing performance in another category. We propose here a collaborative course of work to develop CMS materials to the point that they make major breakthroughs in the performance of Lithium-Sulfur batteries. To date, we have promising early performance data, and indications that the performancecould be greatly improved. This work would allow the materials to be better understood and then optimized so that they can be properly tested in large cells. From a naval perspective, this could allow use in unmanned vehicles, be they underwater or aerial, as the capacity of Li-S batteries is at least double that of current Lithium Ion counterparts. The collaborative project combines expertise in CMS material fabrication and characterization (Georgia Institute of Technology) and Li-S assembly and testing (Monash University).
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 13, 2025
- Source ID
- N000142512064
Entities
People
- Matthew Q. Hill
Organizations
- Monash University
- Office of Naval Research
- United States Navy