New battery idea gets lots of power out of unusual sulfur chemistry

In the realm of battery innovation, sulfur has emerged as a focal point due to its potential for enhancing lithium battery performance. This element is known for its ability to store lithium effectively, promising batteries with remarkable power densities. However, the challenge has always been sulfur's tendency to engage in various chemical reactions, leading to rapid degradation in lithium-sulfur batteries as unwanted byproducts form. Despite years of exploration, the commercial success of lithium-sulfur batteries has remained elusive. Now, a research team from China has discovered a groundbreaking approach that flips sulfur's complex chemistry into an advantage. They have developed a sodium-sulfur battery, where sulfur serves as the primary electron donor, integrating chlorine into its chemical framework. Initial lab results reveal that this innovative battery design boasts impressive energy-to-weight ratios while utilizing cost-effective materials. Sulfur, located just below oxygen in the periodic table, possesses distinct chemical behaviors. Like oxygen, it is capable of forming covalent bonds and is integral in biological systems, notably in two key amino acids. Furthermore, sulfur can both accept and donate electrons, interacting with elements such as chlorine and oxygen. The researchers focused on sulfur's ability to form an eight-atom complex that can release a total of 32 electrons under optimal conditions. Their breakthrough involved creating a system with a cathode made of pure sulfur paired with an anode crafted from aluminum, which functions as a current collector. The electrolytes used in their experiments incorporated significant amounts of aluminum, sodium, and chlorine, specifically an eight Molar aluminum chloride solution combined with a 4.5 Molar sodium salt solution. This configuration not only stabilizes the anode but also facilitates the reactions essential for battery operation.