Venus flytrap-inspired MnP₄/CoP₂ heterojunction with morphology-interface synergistic integration for high-energy-density supercapacitors

Nature-derived distinctive architectures hold great promise for boosting supercapacitor performance through their multi-scale ion transport pathways and robust frameworks. However, simultaneously achieving interfacial charge modulation to break high energy-density limitations remains a fundamental challenge. Drawing inspiration from the hierarchical porosity and stimulus-responsive behavior of Dionaea muscipula (Venus flytrap) leaves, we engineer a biomimetic MnP₄/CoP₂ heterostructure through NH₄F-mediated hydrothermal synthesis and gas-phase phosphidation. The Venus flytrap-like nanosheet-nanowire network establishes dual-scale ion transport pathways: Primary nanosheets (7–10 μm) enable axial electrolyte diffusion highway, while vertically aligned secondary nanowires (~ 700 nm) enhance radial penetration via nanoconfined capillary effects. Concurrently, the MnP₄/CoP₂ heterointerface generates a built-in electric field (work function difference: 0.219 eV), driving interfacial electron transfer and modulating Mn/Co valence states to optimize OH⁻ adsorption energy (−3.51 eV) as confirmed by density functional theory (DFT) calculations. This synergistic integration of morphology and interfacial engineering yields exceptional electrochemical performance: a high areal capacity of 3014 mC·cm⁻² at 1 mA·cm⁻², and 70.58% capacity retention after 8000 cycles. When paired with YP-50 in an asymmetric supercapacitor (ASC), the MnP₄/CoP₂//YP-50 device delivers a high energy density of 88.5 Wh·kg⁻¹ at 798.8 W·kg⁻¹, outperforming state-of-the-art Mn/Co-based systems. In addition, the ASC exhibits exceptional cycling stability (68.29% capacity retention after 10,000 cycles at 5 A·g⁻¹) and practical viability, powering 12 light-emitting diodes (LEDs) for over 10 min. Our work proposes a design principle that integrates the wisdom of natural structures with rational heterostructure configuration, providing a scalable paradigm for developing advanced energy storage materials.