Ion-conductive properties and lithium battery performance of composite polymer electrolytes filled with lignin derivatives

Lignin is the most abundant aromatic material in the Earth’s terrestrial ecosystems. However, very few studies have been conducted on the potential application of lignin derivatives as fillers for electrolytes in lithium batteries to determine cell performance. Herein, a novel electrochemically stable composite polymer electrolyte (CPE) containing a lignin derivative and dilignol was exploited for battery application for the first time. The lignin derivatives improved both the ionic conductivity and mechanical performance of the polymer-based electrolytes. The resulting alterations in the coordination number led to enhanced Li⁺ mobility and consequently, increased conductivity. Notably, the LiFePO₄/Li cell had good stability and recovery capacity, and the Coulombic efficiency was approximately 100%, with a capacity of more than 150 mAh g⁻¹.