Understanding the SEI in fluorine-free sustainable Li- and Na-ion batteries

With this proposal, we will contribute to sustainable battery development by focusing on fluorine-free electrolytes in contact to biobased hard carbon electrodes and transitioning from Li-ion batteries based on scarce and costly Li and graphite to more abundant Na-ion batteries.

Research question

The initial capacity losses when using hard carbon negative electrodes in batteries are a major roadblock for widespread application of the material in batteries that is often mitigated using highly fluorinated and thus potentially hazardous and poisonous compounds. At the core of the project lies thus a systematic study of crucial interfaces such as the solid-electrolyte interphase (SEI) in Li- and Na-ion batteries based on fluorine-free electrolytes in combination with hard-carbon negative electrodes. We will use a combination of electrochemical testing and (operando) photoelectron spectroscopy measurements to understand the SEI formation and interphase stability in these battery systems.

Sustainability aspects

The project target is to enable a cell design that incorporates biobased active materials with recycled metal current collectors together with fluorine-free electrolytes, potentially produced with minimum environmental impact. We expect the battery sustainability gain to be three-fold: replacing fluorine-containing electrolyte components, replacing high environmental footprint graphite in Li-ion batteries, and moving from Li-ion batteries to Na-ion batteries. The project thereby has significant contributions to reaching several UN Sustainable Development Goals concerning affordable and clean energy, sustainable cities, and protection against hazardous compounds.