Interface-engineered one-dimensional core-shell manganese‑cobalt phosphide heterostructures array as advanced electrodes for high-performance supercapacitors

Transition metal phosphides have garnered significant attention as high-performance electrode materials for supercapacitors, owing to their superior electrical conductivity, robust redox activity, and excellent charge storage capabilities. In this study, a novel one-dimensional core-shell manganese‑cobalt phosphide (MCOMP) heterostructure is strategically designed and synthesized to optimize electrochemical performance. The synergistic interaction at the heterointerface between manganese and cobalt phosphides not only enhances electron/ion transport but also provides abundant active sites for faradaic reactions. Meanwhile, the hierarchical core-shell architecture effectively accommodates mechanical strain during repeated cycling, ensuring exceptional structural integrity and long-term stability. Electrochemical characterization demonstrates a remarkable specific capacitance of 309.5 mAh g −1 at 1 A g −1 , outperforming many previously reported TMP-based electrodes. The assembled asymmetric supercapacitor (MCOMP//AC) delivers a high energy density of 40.8 Wh kg −1 at 492.7 W kg −1 , while maintaining 82 % capacitance retention after 5000 cycles with near-ideal Coulombic efficiency (99 %). Electrochemical testing and Density Functional Theory (DFT) confirm that the heterojunction derived from the core-shell structure can significantly enhance charge transport efficiency with the help of a built-in electric field (BIEF). This study provides a rational design strategy for advanced energy storage systems, paving the way for high-performance supercapacitors. One-dimensional needle-like manganese cobalt phosphide material is developed for high-performance hybrid supercapacitors. The constructed core-shell structure alleviates the volume expansion during the charge-discharge process, while the synergistic effects between multiple components and the presence of more active sites effectively enhance the electrochemical performance of the electrodes. • Novel 1D core-shell Mn Co phosphide boosts supercapacitor performance. • Synergistic interface enhances conductivity and redox activity. • Core-shell structure enables efficient charge transfer and long-term durability. • The electrode achieves a high specific capacitance of 2228.5 F g −1 at 1 A g −1 . • DFT calculation reveals the interfacial interaction of the heterostructures.