A new solid electrolyte for batteries is synthesized from two low-cost compounds, expected to reduce the cost of raw materials to $14.42/kg.
University of Science and Technology of China (USTC) develops Li7P3S7.5O3.5 (LPSO) solid electrolyte, a breakthrough in solid-state battery research, Interesting Engineering The new solid electrolyte eliminates the need for expensive Lithium sulfide (Li2S).
Unlike traditional batteries that use a gel or liquid electrolyte to conduct ions between electrodes, solid-state batteries use a solid electrolyte. They promise to overcome the capacity and safety limitations of traditional lithium-ion batteries. The sulfide solid electrolyte plays a key role in the development of this new type of battery.
Solid-state batteries can use either oxides or sulfides as cathode electrodes to increase energy density. Due to their superior performance, sulfides are often considered the most promising option for practical use of all-solid-state batteries in the future, but high cost remains a barrier.
The price of sulfide solid electrolytes typically exceeds $195/kg, far above the $50/kg threshold needed for widespread adoption. Experts say the cost challenge stems from the electrolyte’s complex synthesis process and its heavy reliance on expensive Li2S.
To solve this problem, Ma Cheng, a researcher at USTC, and his colleagues developed an LPSO electrolyte that eliminates the need for Li2S. The new electrolyte is synthesized from two low-cost compounds, reducing the cost of raw materials to just $14.42/kg, less than 8% of the cost of other solid sulfide electrolytes.
Notably, LPSO retains the key benefits of sulfide electrolytes, including compatibility with anodes, ensuring stable performance. It pairs well with high-energy density anodes such as lithium metal and silicon.
A battery made from LPSO and lithium metal has demonstrated stable operation for more than 4,200 hours at room temperature. Ma said the performance is expected to improve further and the team is actively working towards that goal.