Lithium n‐Doped Polyaniline as a High‐Performance Electroactive Material for Rechargeable Batteries

The discovery of conducting lithium‐doped polyaniline with reversible redox chemistry allows simultaneous unprecedented capacity and stability in a non‐aqueous Li battery. This compound (lithium emeraldinate) was synthesized by lithium–proton exchange on the emeraldine base in an anhydrous lithium‐based electrolyte. A combination of UV/Vis‐NIR spectroelectrochemistry, XPS, FTIR, and EQCM characterization allowed a unified description of the chemical and electrochemical behavior, showing facile charge delocalization of the doped states and the reversibility of the redox processes in this form of polyaniline. From a practical point of view, lithium emeraldinate behaves as a high‐capacity organic active material (230 mAh g −1 ) that enables preparation of relatively thick composite electrodes with a low amount of carbon additives and high energy density (460 Wh kg −1 ). Concomitantly, at 1 C rate, 400 cycles were achieved without significant capacity loss, while the coulombic efficiency is greater than 99 %.