High-performance SrMg-MOF/PANI/rGO-based nanocomposite for advanced energy storage and oxygen reduction reaction

초록

The remarkable cyclic stability, high power densities, and other desirable properties of hybrid supercapacitor or supercapattery devices have brought them an abundance of interest in recent years. This research makes use of a hydrothermal synthesis process to create a strontium magnesium metal framework (SrMg-MOF). Adding different amounts of polyaniline (PANI) and reduced graphene oxide (rGO) to SrMg-MOF (SMM) improves its electrochemical performance. At first, a three-electrode setup with working, counter, and reference electrodes is used to assess the electrochemical characteristics of SrMg-MOF/PANI/rGO (SMMPr). The specific capacity (Qs) of SrMg-MOF/PANI (SMMP) and SMMPr are 935 C g- 1 and 1577 C g- 1 by CV, respectively. From the GCD, the obtained values of Qs of SMMP and SMMPr are 912 C g- 1 and 1566 C g- 1, respectively. Most notably, the supercapattery device exhibited an exceptional Qs of 231.74 C g- 1, remarkable energy density (Ed) of 74 Wh kg- 1, and power density (Pd) of 3252 W kg- 1. In addition, a capacity retention of 85.1 % was found in durability testing that included 5000 charge-discharge cycles. The results of this investigation indicate that a material composition of 80/20 % SMMPr has potential for use as an electrode in supercapattery applications. The SMMPr electrocatalyst demonstrated efficient oxygen reduction reaction (ORR) activity in 1 M KOH, with a maximal cathodic current at 0.44 V vs. RHE and an onset potential of 0.67 V. The Koutecky-Levich analysis revealed a 4.5-electron transfer pathway, which suggests a nearly complete 4-electron reduction process. The catalyst maintained approximately 78 % of its initial activity after 5000 s, which is a significant indication of its electrochemical durability.

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