New hybrid cathode increases the energy density of lithium-sulfur batteries

According to foreign media NewAtlas, lithium-sulfur batteries have better energy density and lighter weight, so they have great prospects as a potential successor to lithium-ion batteries. But emerging technologies have their own problems that need to be overcome. Now, engineers have developed a new hybrid cathode for lithium-sulfur batteries, which seems to have a better energy density than existing lithium-ion and lithium-sulfur batteries. Generally, the cathode of a lithium-sulfur battery is composed of a sulfur-carbon matrix, and these sulfurs are constructed in one of two ways. Unfortunately, there is a trade-off-they can choose to have a high energy density in terms of weight or a high energy density in terms of volume, but not both. In the most basic sense, this means that your battery is small and heavy, or light and large. This is the problem addressed by the new research institute. Researchers from the Massachusetts Institute of Technology, Samsung Advanced Institute of Technology, Tongji University, Chinese Academy of Sciences and Songshan Lake Materials Laboratory participated in this research. The researchers built their new hybrid sulfur cathode in an attempt to get the best of both worlds. The solid cathode is made of a combination of pure sulfur and Chevrel phase molybdenum sulfide particles compressed together. Because the end result is high conductivity, it does not require as much carbon-it only requires about 10% compared to the 20% or 30% required by other sulfur cathodes. The team used the new cathode to manufacture a three-layer soft-pack battery with a capacity of 1000-mAh, and said that it is already superior to existing battery technology in some respects. Generally, the energy density of commercial lithium-ion batteries is up to 265 watt-hours/kg and 700 watt-hours/liter. At the same time, the current energy density of lithium-sulfur batteries can reach up to 400 watt-hours/kg and 400 watt-hours/liter. The energy density of the new lithium-sulfur battery can currently reach 360 watt-hours/kg and 581 watt-hours/liter, which means that it has a better weight energy density than lithium ion and a better volume energy density than other lithium-sulfur devices. The team believes that the energy density of the new lithium-sulfur battery will reach 400 watt-hours/kg and 700 watt-hours/liter. But the new lithium-sulfur cathode has a major disadvantage: longevity. For these batteries, this is a fairly common problem, and researchers say they are working to improve the overall battery design to overcome this problem. Other teams are solving it by improving the lithium anode. The research was published in the journal Nature Energy.