Modulating Electrochemical Performance of La₂FeNiO₆/MWCNT Nanocomposites for Hydrogen Storage Inquiries: Schiff-Base Ligand-Assisted Synthesis and Characterization

Since the role of the energetic active materials as cores of energy storage devices is still controversial, the verification and validation of multidimensional compounds with enriched “redox”, “physisorption”, and “spillover” pathways open new implications for the cycling stability and hydrogen storage mechanism. In this study, we investigate the structural–electrochemical contributions of double-perovskite La2FeNiO6 (LFNO) nanostructures with ultralow contents (0.5–3.0 wt %) of attached multiwalled carbon nanotubes (MWCNTs) in electrode texture for hydrogen storage, where the tetradentate Schiff-base ligand’s ability of H2Salen, H2Salpn, and H2Salophen on the growth kinetics rate of porous LFNO was recognized via the combustion method. With the addition of (La + Ni + Fe)/H2Salen in a molar ratio of 1:0.5, outcomes showed a worm-like nanoporous LFNO structure with a crystallized monoclinic phase (P21/c). By applying chronopotentiometry charge–discharge (CCD) tests in a 2.0 M KOH electrolyte, pristine LFNO electrodes created on a Cu substrate achieved a lower discharge capacity of 31.5 mAh g–1 for the 15th cycle at a fixed current of 1 mA. More specifically, the comparative electrochemical properties of LFNO/MWCNT/Cu electrodes highlighted that the MWCNT’s content impacts enhancement of hydrogen storage capacities. In the 15th cycle, a superior discharge capacity of 335.0 mAh g–1 was sustained for the [LFNO/MWCNT1.0%]/Cu electrode as compared with other composite electrodes. The structural modulation of LFNO/MWCNT nanocomposites enhances electrical conductivity and cycling stability, making them suitable for practical applications in the energy industry.