Boosting supercapacitive performance of ultrathin mesoporous NiCo₂O₄ nanosheet arrays by surface sulfation

Abstract

Surface sulfation significantly boosts the supercapacitive performance of ultrathin mesoporous NiCo2O4 nanosheet arrays through enhancing surface reactivity.

Porous Ultrathin NiSe Nanosheet Networks on Nickel Foam for High‐Performance Hybrid Supercapacitors

“…The partial density of states (PDOS) of NiSe (both P63 crystal structures and R3m crystal structures) in Figure 5b show substantially increasedP DOS values aroundt he Fermi level, indicating that the NiSe NNs are quasimetallic and afford high conductivity. [15] The calculated PDOS of Se atoms andN ia toms in NiSe (R3m crystal structures, Figure 5c;P 63 crystal structures, Figure S7) reveal that Se atoms primarily contribute to the enhanced PDOS values. [39] In contrast, the PDOS values of a-Ni(OH) 2 aroundt he Fermi level is close to 0, which is characteristic of ac lassic semiconductor.…”

“…To further understand the improvement in electrochemical energy storage performance of the put‐NiSe NNs sample, first‐principles calculations based on density functional theory (DFT) were performed (the optimized atomic structures are present in Figure S6). The partial density of states (PDOS) of NiSe (both P63 crystal structures and R3m crystal structures) in Figure b show substantially increased PDOS values around the Fermi level, indicating that the NiSe NNs are quasimetallic and afford high conductivity . The calculated PDOS of Se atoms and Ni atoms in NiSe (R3m crystal structures, Figure c; P63 crystal structures, Figure S7) reveal that Se atoms primarily contribute to the enhanced PDOS values .…”

“…The same procedure was also applied on the Ni 3 (NO 3 ) 2 (OH) 4 nanosheets‐coated nickel foam to produce NiSe nanosheets with larger thicknesses. The mass of the activated material on NF was calculated according to previous reports …”

“…Recently,e xcellent TM compounds including TM sulfides, phosphides,n itrides,a nd selenides,p roduced through ion exchange and Kirkendall effects, have been developed to overcome these challenges. [13][14][15] In particular, transition metal selenides (TMSs) have shown extraordinary electrochemical activities and high electricalc onductivity,b oth of which facilitate charge transfer in the electrochemical process. [16] As ar esult, TMSs with 3D configuration have been extensively applied in Li/Na-ion batteries, [17] electrocatalysis, [18] and solar cells.…”

Hierarchical Hollow Bimetal Oxide Microspheres Synthesized through a Recrystallization Mechanism for High‐Performance Lithium‐Ion Batteries

“…[35] Two additional weak satellite peaks are also observed at~789 eV and~804 eV, and the energy gap is around 10 eV between the main peak and the satellite peaks, further indicating the existence of Co 3 + . [36] In terms of the fitting peak of Co2p 3/2 peaks in Figure 5c, the relative atomic ratio of Figure S6). The O 2p spectrum (Figure 5d) is deconvoluted into three peaks at 533.57, 530.78 and 529.71 eV, which are denoted as Oa (caused by the physically adsorbed oxygen), Od (mainly assigned to the defect sites), and Ol (associated with the lattice oxygen in the spinel ZnCo 2 O 4 phase and Co 3 O 4 phase), respectively.…”