Melamine foam supported NiCo2S4/Ag nanowires with charging/discharging induced activation effect for asymmetric supercapacitors

Melamine foam (MF) supported NiCo 2 S 4 /Ag nanowires (AgNWs) were facilely prepared and used as the compressible electrode for the asymmetric supercapacitor (ASC). AgNWs and NiCo 2 S 4 were successively decorated on the surface of MF by a two-step impregnation approach, and the resultant NiCo 2 S 4 /AgNWs/MF exhibited a high deformation-tolerance and outstanding electrochemical behaviors due to the flexible skeleton of MF, high electrical conductivity of AgNWs and high specific capacitance of NiCo 2 S 4 . More importantly, the nanosized NiCo 2 S 4 could be effectively activated by charging/discharging as the NiCo 2 S 4 nanoparticles were gradually converted into NiOOH and CoOOH nanosheets during the repeated charging/discharging cycles, resulting in significantly high capacitance retention (155 % after 2000 charging/discharging cycles). Finally, an ASC was fabricated by using NiCo 2 S 4 /AgNWs/MF as the cathode and MF supported Ti 3 C 2 T x /AgNWs (Ti 3 C 2 T x /AgNWs/MF) as the anode, which showed a high energy density of 28.8 mWh cm −3 at the power density of 754 mW cm −3 .