UNIST and KAIST researchers develop electrolyte to triple battery life

Researchers from UNIST and KAIST have developed a high-performance electrolyte that can triple the lifespan of next-generation lithium metal batteries. The study, published in ACS Nano, introduces a concept called ‘cooperative solvation’ to overcome the limitations of current battery technology.

Lithium metal batteries are considered a key technology for extending the range of electric vehicles because they can theoretically double the capacity of existing lithium-ion batteries. However, they often suffer from rapid capacity loss due to unwanted reactions between the lithium metal and the electrolyte during high-voltage charging.

The research team addressed this by mixing two solvents, ethylene carbonate (EC) and sulfolane (SL), in a 3:7 ratio. While both solvents are typically considered unsuitable for lithium metal batteries because they bind too strongly to lithium ions, mixing them causes the molecules to attract each other, thereby weakening their individual bond with the lithium ions.

In tests conducted at 25°C with a 4.5V charge, the new electrolyte maintained approximately 80% of its initial capacity after 150 charge-discharge cycles. In contrast, conventional carbonate-based electrolytes dropped below the 80% threshold after only about 50 cycles. The researchers expect this technology to be applicable to various next-generation batteries, including high-voltage lithium-ion, sodium-ion, and potassium-ion batteries.