Batteries are ubiquitous in our daily lives, from mobile phones and smart watches to the growing number of electric vehicles. Most of these devices use the well-known lithium-ion battery technology. And while lithium-ion batteries have come a long way since they were first introduced, they still suffer from some familiar drawbacks such as short life, overheating, and supply chain issues with certain raw materials.
US Department of Energy Scientist (DOEs) Argonne National Laboratory is researching solutions to these problems by testing new materials in battery construction. One such substance is sulfur. Sulfur is extremely abundant and cost-effective, and can hold more energy than traditional ion-based batteries.
In the new study, researchers advanced sulfur-based battery research by creating a layer within the battery that adds energy storage capacity while nearly eliminating the traditional problem of sulfur batteries causing corrosion.
“These results indicate that the redox-active interlayer may have a significant impact on the development of Li-S batteries. We are one step closer to seeing this technology in our daily lives. — Wenqian Xu, beamline scientist APS
A promising battery design combines a sulfur-containing positive electrode (cathode) with a lithium metal negative electrode (anode). Between these components is an electrolyte, a substance that allows ions to pass between the ends of the battery.
Early lithium-sulfur (Li-S) batteries performed poorly because the sulfur species (polysulfides) dissolved in the electrolyte and caused corrosion. This polysulfide shuttling effect negatively impacts battery life and reduces the number of times the battery can be recharged.
To prevent this polysulfide shuttle, previous researchers tried to place a redox-inert intermediate layer between the cathode and anode. the term ?““Redox inert” means that the material does not undergo electrode-like reactions. However, this protective interlayer is heavy and dense, which reduces the battery’s energy storage capacity per unit weight. Also, you can’t reduce the shuttle enough. This has proven to be a major barrier to commercialization of Li-S batteries.
To address this, researchers developed and tested a porous sulfur-containing interlayer. Laboratory tests showed about three times higher initial capacity for his Li-S battery with this active interlayer as opposed to an inert interlayer. Even more impressively, cells with active interlayers maintained high capacity over 700 charge-discharge cycles.
“Previous experiments with cells with a redox-inactive layer only suppressed shuttle, but the layer added extra weight, thus sacrificing energy for a given cell weight.” Argonne chemist and dissertation. ?“In contrast, our redox active layer increases energy storage capacity and suppresses the shuttle effect. ”
To further study the redox active layer, the team conducted an experiment 17-BM Beamline of Argonne’s Advanced Photon Source (APS), DOEs Office of Science User Facility. Data collected by exposing cells containing this layer to her X-ray beam allowed the team to confirm the benefits of the intermediate layer.
The data confirmed that the redox-active intermediate layer reduces shuttle, reduces harmful reactions within the battery, and increases the battery’s capacity to hold more charge and last more cycles.“These results indicate that the redox-active interlayer may have a significant impact on the development of Li-S batteries. APS.?“We are one step closer to seeing this technology in our daily lives. ”
Going forward, the team hopes to evaluate the potential for growth in redox-active interlayer technology. ?“We want it to be thinner and lighter,” says Guiliang Xu.
Original: Lithium-sulphur batteries are one step closer to powering the future
Than: Argonne National Laboratory
