Novel MoS₂-sputtered NiCoMg MOFs for high-performance hybrid supercapacitor applications

Supercapacitors are considered one of the possible next-generation clean energy storage devices; however, their specific capacitance still needs improvement regarding electrode materials. Herein, we prepared three types of electrode materials, i.e., pure NiCoMg MOFs deposited on Ni-foam (abbreviated as P-NiCoMg), NiCoMg MOFs deposited on MoS₂-sputtered Ni-foam (signified as SN-NiCoMg), and MoS₂-sputtered NiCoMg MOFs deposited on Ni-foam (shortened as S-NiCoMg). SEM and XRD revealed a successful preparation of cactus-like microstructure and coexistence of MoS₂ and NiCoMg MOFs in the material of interest S-NiCoMg electrode. Interestingly, the S-NiCoMg electrode showed a specific capacitance of 2000 F/g, which is 1.8 and 1.4 times higher than the P-NiCoMg and SN-NiCoMg electrodes, respectively. This indicates the efficacy of enhancing specific capacitance electrode materials using MoS₂ sputtering. Further, an asymmetric supercapacitor device of S-NiCoMg electrode with activated carbon demonstrated excellent specific capacitance, energy density, and power density of 211 F/g, 107 Wh/kg, and 1350 W/kg, respectively. Dunn's model revealed that most charge storage is diffusion controlled (i.e., 64 %, 58 %, and 53 % at 3, 5, and 10 mV/sec, respectively). Overall, S-NiCoMg electrode material demonstrated excellent potential to be used as functional, affordable, recyclable, and low-cost supercapacitors for energy storage applications.