Lithium-ion batteries are the favoured technology for powering electric vehicles at the moment, but they’re too expensive for long-term grid-scale energy storage systems, and lithium is getting increasingly difficult to come by.
While lithium has a number of advantages, including a high energy density and the ability to be paired with renewable energy sources to allow grid-level energy storage, lithium carbonate prices have reached an all-time high. Furthermore, because of the enormous environmental costs and the possibility for human rights breaches, many countries are unwilling to approve lithium mining.
New research conducted at the University of Houston and published in Nature Communications suggests ambient temperature solid-state sodium-sulfur battery technology as a viable alternative to lithium-based battery technology for grid-level energy storage systems, as governments and industries around the world scramble to find energy storage options to power the clean energy transition.
Yan Yao, Cullen Professor of Electrical and Computer Engineering, and his colleagues created a homogeneous glassy electrolyte that allows for reversible sodium plating and stripping at higher current densities than previously feasible.
“The quest for new solid electrolytes for all-solid sodium batteries must concurrently be low cost, easily fabricated, and have incredible mechanical and chemical stability,” said Yao, who is also principal investigator of the Texas Center for Superconductivity at the University of Houston (TcSUH). “To date, no single sodium solid electrolyte has been able to achieve all four of these requirements at the same time.”
The researchers discovered a new type of oxysulfide glass electrolyte that might meet all of these criteria at the same time. The electrolytes were made at room temperature using a high-energy ball milling technique. “The oxysulfide glass has a distinct microstructure, resulting in a completely homogeneous glass structure,” said Ye Zhang, who works as a research associate in Yao’s group. “At the interface between sodium metal and the electrolyte, the solid electrolyte forms a self-passivating interphase that is essential for reversible plating and stripping of sodium.”
“The new structural and compositional design strategies presented in this work provide a new paradigm in the development of safe, low-cost, energy-dense, and long-lifetime solid-state sodium batteries,” Zhang added.
Read the entire study here.