Study of interfacial synergy in strontium-based organic framework/polyaniline/nanoporous graphene ternary composite as positive electrode for battery-supercapacitor hybrid devices

The escalating global demand for reliable and sustainable energy sources has intensified the need for advanced supercapacitor technologies capable of bridging the gap between capacitors and conventional batteries. However, the development of novel electrode material governing competitive specific capacity, energy and power density is critical. In this work, strontium-benzene tetracarboxylic acid metal-organic framework (Sr-BTCA) incorporated with PANI and NPG was synthesized and evaluated as an electrode material. Their synergistic integration of these components exploits their individual advantages. The electrochemical measurement demonstrates that Sr-BTCA/PANI/NPG based composite delivers specific capacity of 645.5 C g^-1 at 1.5 A g^-1. Furthermore, the assembled two electrode hybrid device exhibit maximum energy density of 74.5 Wh kg^-1. Linear and quadratic models were applied on the experimental data to estimate the capacitive and diffusive contributions. The quadratic model provides a better fit on experimental as compared to the linear model which reveals that capacitive-controlled charge storage dominates at higher scan rates, confirming fast electrochemical kinetics. These results highlight the strong synergistic interaction among the MOF, PANI, and NPG components, positioning the Sr-BTCA/PANI/NPG composite as a promising electrode material for high-performance supercapacitor applications.