Bimetal-organic framework derived Cu(NiCo)₂S₄/Ni₃S₄ electrode material with hierarchical hollow heterostructure for high performance energy storage

Rational design of electrical active materials with high performance for energy storage and conversion is of great significance. Herein, Cu(NiCo)₂S₄/Ni₃S₄, a three-dimensional (3D) hierarchical hollow heterostructured electrode material, is designed by etching the well-defined bimetal organic framework (MOF) via sequential in-situ ion-exchange processes. This trimetallic sulfides with unique structure provide large surface area, hierarchical pore distribution and enhanced electrical conductivity, can enrich the active sites for redox reactions, facilitate electrolyte penetration and rapid charge transfer kinetics. As a result, the Cu(NiCo)₂S₄/Ni₃S₄ electrode exhibits a high specific capacitance of 1320 F/g at 1 A/g and excellent rate performance (only 15% of capacitance is attenuated when the current density is increased by 20 times). Furthermore, a fabricated hybrid supercapacitor of Cu(NiCo)₂S₄/Ni₃S₄/AC can deliver a maximum energy density of 40.8 Wh/kg, remarkable power density of 7859.2 W/kg and superior cycling stability (85% retention of capacitance after 5000 cycles), demonstrating great potential for practical applications in energy storage and conversion devices.