Manganese–Iron–Cobalt Telluride Nanocomposite Hollow Nanocubes Armored with Interconnected Porous Nanosheets: A Holistic Design for High-Performance Battery-Type Electrodes

Bridging the energy-power gap in energy storage demands battery-type electrodes that overcome the intrinsic trade-offs between capacity, rate capability, and cycling stability. Herein, we introduce a dual-engineering strategy that integrates a conductive heterostructured nanocomposite of manganese-iron-cobalt tellurides (MnFeCoTe) with a precisely controlled hollow hierarchical architecture. The material is synthesized through a templated hydrothermal transformation, where well-defined MnFe-Prussian blue analogue (MnFe-PBA) nanocubes are converted into hollow MnFeCoTe nanocomposite nanocubes uniformly sheathed with interconnected nanosheets. This distinctive morphological evolution is driven by a Kirkendall effect during the simultaneous tellurization and cobalt incorporation, creating a hollow core for strain accommodation and a conductive, high-surface-area shell for rapid ion/electron transport. We optimized the tellurization temperature, finding that 180 °C yields the optimal hierarchical architecture, denoted as MnFeCoTe-180, which balances complete phase conversion with structural integrity. The heterostructured nanocomposite system, comprised of intimately mixed binary telluride phases (MnTe, FeTe, and CoTe), provides intrinsic metallicity and rich multielectron redox activity through synergistic interfacial effects, while the architecture ensures full electrolyte accessibility and mechanical robustness. The resulting MnFeCoTe-180 electrode delivers a high specific capacity of 1455 C g^-1 at 1 A g^-1, exceptional rate performance (80.25% capacity retention at 45 A g^-1), and outstanding long-term cyclability (97.22% retention after 10,000 cycles). In a full asymmetric hybrid supercapacitor, the device achieves a high energy density of 65 Wh kg^-1 at 802.46 W kg^-1 and maintains 48.1 Wh kg^-1 at 37 kW kg^-1, with 90.25% capacity retention over 10,000 cycles. This work demonstrates a holistic design paradigm, where targeted nanocomposite composition and rational nanoarchitecture are combined to unlock transformative electrochemical performance, setting a new benchmark for next-generation faradaic electrodes.