Rational design of three-dimensional branched NiCo-P@CoNiMo-P core/shell nanowire heterostructures for high-performance hybrid supercapacitor

Abstract Owing to the dramatically enhanced charge-mass transport and abundant electrochemically active sites, transition metal compound electrodes are increasingly attractive for achieving high-performance supercapacitors (SCs). Here, we report the fabrication of nickel foam supported three-dimensional (3D) branched nickel-cobalt phosphides@tri-metal cobalt-nickel-molybdenum phosphides core/shell nanowire heterostructures (denoted as NiCo-P@CoNiMo-P) as high-performance electrode materials for hybrid supercapacitors. The presence of multiple valences of the cations in such NiCo-P@CoNiMo-P enables rich redox reactions and promoted synergy effects. Benefiting from their collective effects, the resulting electrode demonstrates high specific capacity of 1366 C g−1 at 2 A g−1 (2.03 C cm−2 at 2 mA cm−2) and 922 C g−1 at 10 A g−1, as well as good cycling stability (retaining ∼94% of the initial capacity after 6000 cycles at 15 A g−1). A hybrid SC using the NiCo-P@CoNiMo-P as the positive electrode and N-doped rGOs as the negative electrode exhibits a high energy density of 81.4 Wh kg−1 at a power density of 1213 W kg−1 and a capacity retention of 132% even after 6000 cycles at 10 A g−1. Our findings can facilitate the material design for boosting the performance of transition metal compounds based materials for fast energy storage.