Researchers have developed a lithium-sulfur (Li-S) battery with an improved iron sulfide cathode to address stability and safety issues commonly associated with lithium-ion batteries. Li-S batteries have the potential to hold more energy than traditional ion-based batteries, making them a promising alternative for portable devices. To make Li-S batteries stable at high temperatures, researchers have proposed using a carbonate-based electrolyte to separate the two electrodes. However, the sulfide in the cathode can dissolve into the electrolyte, causing the cell to lose capacity quickly. The team wondered if adding a layer between the cathode and electrolyte could reduce this corrosion without reducing functionality and rechargeability.
In initial tests, the researchers coated iron sulfide cathodes with different polymers and found that polyacrylic acid (PAA) performed the best, retaining the electrode’s discharge capacity after 300 charge-discharge cycles. They then incorporated a PAA-coated iron sulfide cathode into a prototype battery design, along with a carbonate-based electrolyte, a lithium metal foil, and a graphite-based anode. Both pouch cell and coin cell battery prototypes were produced and tested by the team. After more than 100 charge-discharge cycles, the pouch cell showed no substantial capacity decay, even after being folded and cut in half. The coin cell retained 72% of its capacity after 300 charge-discharge cycles.
The researchers also applied the polymer coating to cathodes made from other metals, resulting in stable capacity over 300 charge-discharge cycles for lithium-molybdenum and lithium-vanadium batteries. Overall, the results suggest that coated cathodes could lead to safer Li-S batteries with long lifespans, as well as efficient batteries using other metal sulfides. This advancement has the potential to improve the performance and safety of rechargeable batteries used in various portable devices, such as toys, handheld vacuums, and e-bikes.
The use of sulfur in lithium-ion batteries is appealing due to its low cost and potential to store more energy than lithium-metal oxides and other materials. However, stability and safety concerns have hindered the widespread adoption of sulfur-based batteries. By developing a Li-S battery with an improved iron sulfide cathode and polymer coating, researchers have made significant progress in addressing these challenges. The battery prototypes produced by the team showed stable capacity over multiple charge-discharge cycles and remained functional even after being subjected to physical damage.
The research has implications for improving the performance of rechargeable batteries in portable devices and could potentially lead to the development of more efficient and safe battery technologies. The funding received for this project highlights the importance of continued investment in battery research to drive innovation and address the challenges associated with current energy storage solutions. Overall, the development of a stable and efficient Li-S battery with an improved cathode design represents a significant step forward in advancing battery technology and meeting the growing demand for reliable and safe energy storage solutions in various industries.
