Toward high-performance energy storage horizon: Utilizing binary manganese-nickel phosphides and nitrogen-enriched porous hydrothermal carbons

As the global emphasis on sustainable energy solutions intensifies, high-performance supercapacitors that afford superior power and energy densities, along with long-term cycling durability, remain critically important as fundamental building blocks for advanced energy storage systems. Herein, an innovative strategy is developed to engineer hierarchical architectures comprising manganese-nickel bimetallic phosphides (Mn-Ni-P) directly decorated on nickel sulfide (Ni-S) nanowires (NWs) grown on nickel foam (NF), which are directly employed as positive electrodes in asymmetric supercapacitors (ASCs). The fabricated electrodes benefit from a high specific capacity of 224 C g −1 (at 2.5 A g −1 ), while retaining over 87.6% of their initial capacity after 5000 charge/discharge cycles. Meanwhile, nitrogen-enriched porous hydrothermal carbons (NPHCs)—leveraging their highly porous structure and nitrogen heteroatom doping, are employed as negative electrodes in the fabricated ASCs. The assembled negative electrodes harness a high specific capacitance of 177 F g −1 (at 0.75 A g −1 ), while retaining over 94.1% of their initial capacitance after 5000 charge/discharge cycles. The assembled ASCs, operating across a fairly broad potential window (1.65 V), not only deliver an exceptional energy density of 49.7 W h kg −1 at a competitive power density of 456.8 W kg −1 but also exhibit remarkable cycling durability. The advanced asymmetric design, together with the encouraging electrochemical performance presented herein, renders these ASCs highly promising for next-generation high-performance electronics.