Graphene wrapped porous polyaniline/manganese oxide nanocomposites with enhanced structural stability and conductivity for high‐performance symmetric supercapacitor

Abstract Manganese oxides have emerged as promising electrode materials for supercapacitors. Despite extensive efforts to improve their conductivity and structural stability through various manganese oxide/conductor nanocomposites, achieving efficient and reliable energy storage electrode materials has remained challenging. In this study, we propose a meticulous “dual enhancement” strategy, where three‐dimensional (3D) nanostructured polyaniline/manganese oxide composites (PM) are synthesized via an in situ method and further integrated with graphene wrapping to form polyaniline/manganese oxide/graphene nanocomposites (PMG). Electrochemical characterization reveals that PMG exhibits a remarkable specific capacitance of up to 403 F g −1 (at 1 A g −1 ), with a favorable capacitance retention of 80.2% after 5000 cycles, along with a wide potential window. This enhancement is attributed to the synergistic effects of polyaniline, which provides a supportive framework and electron transport pathways, and graphene, which offers external protection and enhances conductivity pathways. Assembled symmetrical supercapacitors demonstrate outstanding energy density (32.7–23.3 Wh kg −1 ) and power density (720–4500 W kg −1 ) at a high operating voltage of 1.8 V, surpassing the performance of many reported high‐performance supercapacitors. This study provides valuable insights for advancing manganese oxide electrode materials and is expected to catalyze their widespread adoption in energy storage applications. Highlights “Dual enhancement” is implemented by PANI supporting and rGO wrapping. The conductivity and structural stability of composite electrode is greatly enhanced. Improved capacitance (403 F g −1 , 1 A g −1 ) and cycling stability (80.2%) is achieved. The symmetrical supercapacitor has high voltage and energy density (32.7 Wh kg −1 ).