A Lignosulfonate Binder for Hard Carbon Anodes in Sodium-Ion Batteries: A Comparative Study

An important factor in the development of sodium-ion batteries (SIBs) is use cheap and sustainable materials. Sodium lignosulfonate, a lignin derivative, demonstrated here as an attractive, “green”, water-soluble, potentially cost-effective binder for hard carbon anodes SIBs. A comparison its battery cycling performance made against other binders including sodium carboxymethyl cellulose lignin, obtained from kraft process, well alginate, derived algae. Apart which requires processing N-methyl-2-pyrrolidone, three are water-soluble. Lignosulfonate shows comparable or better performance, with high capacity retention stability, when using 1 M NaPF6 propylene carbonate ethylene carbonate:diethyl electrolytes both half- full-cells (against Prussian white cathode). Further improvements observed styrene-butadiene rubber co-binder. X-ray photoelectron spectroscopy demonstrates similar solid electrolyte interphase compositions after initial insertion lignosulfonate binders. However, subsequent cycling, surface layer composition thickness found to be dependent on binder. For lignosulfonate-based electrode, appears thicker but comprises smaller fraction carbon–oxygen species.