3D porous Mn₃O₄/PANi electrodes similar to reinforced concrete structure for high performance supercapacitors

A tetraphenyl porphyrin tetrasulfonic acid (TPPS)-modified three-dimensional porous Mn₃O₄/PANi composites electrode was prepared, which has excellent electrical conductivity and rate performance. The conductivity and stability of polyaniline (PANi) gels have been improved due to the doping of TPPS and its conjugated molecular structure. Furthermore, the Mn₃O₄/PANi composites gel similar to reinforced concrete structure were prepared by coating PANi cross-linked by TPPS on one-dimensional Mn₃O₄ nanorods. On the one hand, modified PANi gel act as a functional coating of Mn₃O₄ nanorods, providing structural protection and providing more active sites. On the other hand, the overlapping Mn₃O₄ nanorods and PANi gel form a three-dimensional porous network structure, which has a high specific surface area, provides more channels for the transfer of electrons and electrolyte ions, and effectively improves the conductivity of Mn₃O₄. The specific capacitance of the composite electrode can reach 422 F g⁻¹ at a current density of 0.5 A g⁻¹, and the specific capacitance can reach 265 F g⁻¹ at a high current density of 10 A g⁻¹. After 2000 cycles, the capacity loss was only 11%. And the charge transfer resistance is only 1.2 Ω. These excellent electrochemical performances, as a result of the stable structure formed by TPPS modification and three-dimensional porous morphology, suggesting that these composites have an enormous potential in energy application.