Hierarchical layer to layer of ternary heterostructure: Nanograin nickel carbonate embedded layered NiMnO 3 ‐rGO‐Co 3 O 4 composite array as a high‐performance electrode for hybrid supercapacitors

Abstract

Heterostructured metallic electrode materials fabricated by altering the structurally engineered morphologies are promising in ameliorating electrodes' functionality in energy storage applications. Effective and novel double-shell sandwich-like NiCO3/NiMnO3-rGO-Co3O4 (Ni-NMO-rGO-CoO) nanoflake array (NFA) heterostructures were prepared on highly conducting 3D Ni foam using a two-step hydrothermal process. rGO wrapping on the NiCO3 embedded NiMnO3 (Ni-NMO) nanocomposite flakes improved the cycling stability and avoided volume expansion by acting as an interlayer. The surface decorated Co3O4 nanograins showed a uniform distribution over the rGO wrapped Ni-NMO and facilitated the pathways for fast ion diffusion kinetics to enhance the specific capacity of the electrode. The layer to layered Ni-NMO-rGO-CoO NFA electrode yielded an ascendant specific capacity of 188.8 mA h g−1 (3.9 F cm−2) at 1 mA g−1. The fabricated all-solid-state Ni-NMO-rGO-CoO//AC hybrid supercapacitors (HSCs) showed a superior energy density of 57.2 W h kg−1 at 472.2 W kg−1 with 97.7% capacitance retention after 10 000 cycles. The fabricated HSCs have potential applications in portable electronics. The Ni-NMO-rGO-CoO NFA ternary layered architecture offers a promising approach for fabricating high-performance hierarchical composite array electrodes for next-generation energy storage devices.