Electrochemical behavior of silicon oxycarbide as negative electrodes in lithium- ion batteries: a study of binder–ionic liquid electrolytes

The pressing need for sustainable and efficient energy storage technologies, driven by climate change, has positioned lithium-ion batteries (LIBs) at the forefront of current research. Their high energy density and wide applicability, from portable electronics to electric mobility, make them highly attractive, yet persistent issues such as safety, cost, and raw material sustainability must be addressed.

Nitrogen-doped silicon oxycarbides (SiOC) and ionic liquids (ILs) represent promising alternatives to conventional electrode and electrolyte materials. SiOCs exhibit greater structural robustness and higher storage capacity than graphite, while ILs offer non-flammability, broad electrochemical stability windows, and tunable physicochemical properties. Despite these advantages, their joint application remains scarcely explored.I n this study, SiOC electrodes prepared with two different binders: poly(acrylic acid) (PAA) and cyclized poly(acrylonitrile) (c-PAN), were evaluated in IL-based electrolytes containing phosphonium and pyrrolidinium cations paired with the bis(fluorosulfonyl)imide anion, as well as in a commercial electrolyte. The c-PAN system delivered 25–30% higher delithiation capacity compared to PAA, alongside a superior initial coulombic efficiency (67% vs. 62%). Long-term cycling retained 75–80% of the original capacity after 1000 cycles at 1.6 A g?¹. These results demonstrate that optimizing the binder–IL combination significantly enhances the electrochemical performance of SiOC electrodes, offering a pathway toward safer and more efficient LIBs.

Dr. Ivonne E. Monje is a chemist specializing in electrochemistry, materials science, and energy storage. She earned her PhD in Chemistry from the University of Alicante, Spain, and completed postdoctoral research at Université du Québec à Montréal (UQAM), Canada, and the University of São Paulo (USP), Brazil. She is currently a full-time professor at the University of Pamplona, Colombia. Her research focuses on silicon oxycarbides, ionic liquids, and biomass-derived carbons for lithium-ion batteries and supercapacitors, while also leading outreach projects that foster chemistry education and sustainable technologies in local communities.