Electrochemical Performance of Manganese Coordinated Polyaniline

Abstract Manganese (II) coordinated polyaniline (PANI‐Mn) is designed as an energy‐storage electrode to improve electrochemical cycling stability of conductive polymer‐based supercapacitors. A PANI‐Mn electrode is synthesized through electro‐polymerization and hydrothermal coordination processes. A tetrahedron coordination structure is formed between manganese (II) dichloride and neighboring imino nitrogen to enforce the bonding strength of conjoint aniline units, restraining excessive volume expansion of the PANI molecule chain. Specific capacitance is enhanced from 350 F g −1 of PANI to 810 F g −1 of PANI‐Mn at 1 A g −1 . Cycling capacitance retention is improved from 61% of PANI to 88% of PANI‐Mn at 5 A g −1 for 1000 cycles. PANI‐Mn shows larger response current than PANI at the same potential. First principle calculations prove that PANIs‐Mn exhibits higher density of state at Fermi level than PANI. The conjugated electron delocalization is strengthened in transitional metal‐coordinated conductive polymer, causing the improved conductivity of PANI‐Mn. Furthermore, an all‐solid‐state symmetric supercapacitor based on a PANI‐Mn electrode exhibits an energy density of 51.38 Wh kg −1 at a power density of 850 W kg −1 and a considerable cycling life of 82% after 1000 cycles at 5 A g −1 . PANI‐Mn coordination polymer exhibits enhanced electrochemical stability, thus showing promise for energy storage application.