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

Melamine foam (MF) supported NiCo2S4/Ag nanowires (AgNWs) were facilely prepared and used as the compressible electrode for the asymmetric supercapacitor (ASC). AgNWs and NiCo2S4 were successively decorated on the surface of MF by a two-step impregnation approach, and the resultant NiCo2S4/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 NiCo2S4. More importantly, the nanosized NiCo2S4 could be effectively activated by charging/discharging as the NiCo2S4 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 NiCo2S4/AgNWs/MF as the cathode and MF supported Ti3C2Tx/AgNWs (Ti3C2Tx/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.