A team of researchers from the University of Bayreuth in Germany, in collaboration with research partners from China, has developed a solid-state lithium-metal battery the exhibits both high energy density and stability, and is easy to produce. Using a novel nitrate-based additive, the researchers resolved incompatibility issues in battery electrolytes, underscoring the importance of molecular design in creating effective additives for quasi-solid-state electrolytes.
The team has, for the first time, succeeded in resolving the incompatibility between lithium nitrate and 1, 3‐dioxolane (DOL) for use in quasi-solid battery electrolytes. The advancement holds significant implications for the design and production of solid-state batteries, enabling the development of solid-state lithium metal batteries that are not only very safe and durable but also relatively simple to make. Furthermore, the process fits in with existing methods for manufacturing conventional liquid batteries.
‘At the same time, the batteries’ solid-state nature ensures a high level of safety, while their manufacturing remains straightforward,’ said Professor Francesco Ciucci, chair of electrode design for electrochemical energy systems at the University of Bayreuth. ‘We demonstrated the approach’s universality by creating various types of lithium-metal batteries. Notably, the manufactured pouch Li-S cell exhibits superior performance compared to previously documented pouch Li-S cells.’
Professor Ciucci’s research team introduced a new additive, triethylene glycol dinitrate, specifically designed to enable the polymerisation of DOL. The research team showed that, concomitant with the polymerisation, the formation of a nitrogen-rich solid electrolyte interphase layer suppresses detrimental parasitic reactions and also increases the battery’s efficiency.
Based on the study findings, several battery cells were developed. Among them, a lab-scale, button-type cell could be stably charged and discharged more than 2,000 times. Excitingly, A 1.7 Ah Li-S pouch cell with high energy density of 304 watt-hours per kilogram and stable cycling was also fabricated. ‘This study underscores the importance of molecular structure design in creating effective additives for quasi-solid-state electrolytes,’ Ciucci said. ‘It represents a significant advancement in the practical feasibility of employing poly-DOL-based quasi-solid-state electrolytes in lithium metal batteries.’
The research has been published in Energy & Environmental Science.