The MOF-originated NiCu-POx/NGQD for efficient supercapattery devices and hydrogen evolution reaction

Abstract

Due to the high viability of electrochemical energy resources and their storage techniques in the present climate, supercapacitors and water-splitting electrolysis have seen dramatically increased attention in modern days. We presented the synthesis of nickel-copper phosphate (NiCu-POx) nanosheets from the phosphorization of the nickel-copper metal-organic framework (NiCu-MOF) at a limited temperature. Further, the addition of nitrogen-doped graphene quantum dots (NGQD) in the Ni–Cu-POx was also studied. SEM, XRD, and XPS were used to analyze the structural and elemental composition of the synthesized materials. Further, Brunauer-Emmett-Teller (BET) measurements showed an enhancement in surface area when NGQDs were introduced into the heterostructure of NiCu-POx. An extraordinary value of specific capacity (1431 C-g−1 at 1.4 Ag-1) was achieved with NiCu-POx/NGQDs. Supercapattery device (NiCu-POx/NGQDs//PANI@AC) was fabricated with polyaniline doped activated carbon as the negative and NiCu-POx/NGQDs as the positive electrode. The specific capacity of the real device (NiCu-POx/NGQDs//PANI@AC) was 224 C-g−1 at 2.0 Ag-1. The energy density for this asymmetric device (NiCu-POx/NGQDs//PANI@AC) was 73 Whkg−1 at 980 Wkg-1 power density. The device (NiCu-POx/NGQDs//PANI@AC) was subjected to 10,000 charge-discharge cycles to test its durability. After 10,000 cycles NiCu-POx/NGQDs//PANI@AC demonstrates an outstanding 86% reservation of capacity. The NiCu-POx/NGQDs showed a small overpotential of 138 mV during the 24 h HER test. According to our findings, NiCu-POx/NGQDs proved to be a suitable electrode material for prospective supercapattery and HER applications.