A synergistic perovskite-transition metal carbide hybrids for high-performance supercapacitors

초록

The strategic integration of disparate material classes presents a powerful pathway for engineering advanced electrodes that transcend the performance limitations of individual components. This study demonstrates the rational design of SrFeO3@Mo2C and SrFeO3@W2C hybrid architectures, which synergistically combine the rapid charge delivery of electric double-layer capacitive carbides with the high specific capacity of Faradaic pseudocapacitive perovskites. Synthesized via a combined chemical reduction and hydrothermal method, the composites were thoroughly characterized, with XPS confirming strong interfacial electronic coupling that facilitates charge redistribution. Electrochemically, the SrFeO3@Mo2C hybrid delivered a high specific capacitance of 786 F g(-1) at 1 A g(-1), significantly outperforming the individual components. Kinetic analysis based on the power-law relationship (i = av(b)) yielded a b value of similar to 0.53, indicating a mixed charge storage mechanism dominated by diffusion-controlled Faradaic processes associated with the SrFeO3 redox reactions. The Mo2C conductive scaffold facilitates rapid electron transport and lowers the charge transfer resistance, thereby accelerating the electrochemical reaction kinetics and improving the utilization of active sites. This is further supported by a low charge-transfer resistance from EIS. The hybrid electrode exhibited remarkable cycling stability, retaining 89.2% of its initial capacitance over 5000 cycles. When configured into all-solid-state symmetric supercapacitors with a PVA-KOH gel electrolyte, the devices achieved a high energy density of 50 Wh kg(-1) at a power density of 0.75 kW/kg. These findings underscore the efficacy of carbide-perovskite hybridization in creating multifunctional electrode materials for next-generation, high-performance energy storage systems.

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