New acid-base bifunctional catalyst efficiently produces key lithium-ion battery material

Ethyl methyl carbonate (EMC) is a linchpin of lithium-ion battery electrolytes, making up 30–35% of their composition due to its unique balance of solubility, safety, and stability. As global demand for batteries surges—driven by electric vehicles and renewable energy storage—efficient EMC production has become increasingly vital. However, traditional synthesis via transesterification of dimethyl carbonate (DMC) and diethyl carbonate (DEC) faces significant hurdles: strong acid catalysts cause DMC to hydrolyze into methanol and carbon dioxide, while alkaline catalysts like sodium alkoxides are poorly soluble in the non-polar reaction system, leading to low conversion rates and wasted resources.

A team of researchers from Qingyuan Innovation Laboratory, East China Engineering Science and Technology Co. Ltd., and Fuzhou University has now solved this dilemma with [DBU⁺][IM^-]@UiO-66, a novel acid-base bifunctional catalyst. This innovative material combines two key components: UiO-66, a zirconium-based metal-organic framework (MOF) with a porous structure and acidic sites from intentional defects, and [DBU⁺][IM^-], an ionic liquid that contributes strong basic sites. By immobilizing the ionic liquid within UiO-66’s pores, the catalyst creates a synergistic environment where acid and base sites work in tandem—acidic sites activate DMC and DEC by interacting with their carbonyl groups, while basic sites promote the formation of reactive intermediates, accelerating the conversion to EMC.

In laboratory tests, the catalyst delivered impressive results: under optimal conditions (100°C, 5-hour reaction, 8 wt% catalyst dosage relative to DMC), it achieved a 62% EMC yield and 99.5% selectivity, meaning nearly all reactants were converted into the desired product. Equally notable is its stability: after six reuse cycles, the yield only dropped slightly from 62% to 58.9%, with UiO-66’s robust structure preserving the catalyst’s integrity.

“This catalyst overcomes the trade-offs that have plagued EMC synthesis,” explained Zhaoyang Qi, a corresponding author. “By combining acid and base sites in a single, reusable structure, we’ve eliminated side reactions and boosted efficiency—key for scaling up to industrial production.”

This advancement not only streamlines EMC manufacturing but also supports the transition to clean energy by ensuring a reliable supply of high-quality battery components.