Natural-Wood-Derived Lignosulfonate Ionomer as Multifunctional Binder for High-Performance Lithium–Sulfur Battery

It is highly desirable to develop advanced electrode structures of lithium–sulfur (Li–S), which enable high energy density, long life, low cost, and environmental benignity. In particular, suppression of polysulfide (PS)-shuttle behavior that occurs during electrochemical reaction in Li–S batteries is the most important challenge for practical, large-scale applications. In this work, a natural-wood-derived polymer, lignosulfonate sodium salt (LSS), is employed as a binder material for Li–S, showing superior capacity and cycle retention because of its unique chemical structure. LSS with amphiphilic functional groups can easily disperse hydrophobic electrode components in water and effectively block PS dissolution by its electrostatic repulsion force. Moreover, with enhanced Li ionic conductivity, the rate capability of the S cathode is maintained at ∼661 mA h g–1 at a current rate of 1675 mA g–1 and stable areal capacity of ∼1.55 mA h cm–2 is obtained with pristine S active material.