A MnCo₂O₄@NiMoO₄ Core‐Shell Composite Supported on Nickel Foam as a Supercapacitor Electrode for Energy Storage

Abstract

A MnCo2O4@NiMoO4 composite was synthesized on nickel foam by a two‐step method. The composite has a core‐shell structure in which MnCo2O4 nanoneedles are wrapped by NiMoO4 nanoflakes. The MnCo2O4@NiMoO4/Ni foam is applied as a binder‐free electrode for supercapacitors and it achieves a specific capacitance of up to 1718 F g−1 at a current density of 1 A g−1, and 84 % capacitance retention after 6000 charge‐discharge cycles. The capacitance of the MnCo2O4@NiMoO4 composite is much higher than MnCo2O4 nanoneedles and NiMoO4 nanoflakes alone. Moreover, a hybrid supercapacitor is assembled by applying the MnCo2O4@NiMoO4/Ni foam as the positive electrode, activated carbon/Ni foam as the negative electrode. The hybrid supercapacitor reaches an energy density of up to 42.3 W h kg−1 at a power density of 797 W kg−1, a power density of 6256 W kg−1 at an energy density of 17.4 W h kg−1, and 86 % capacitance retention after 2000 charge‐discharge cycles. The results suggest that the rational design of electrode materials with such structure and composition is an effective strategy to improve electrochemical performance.

Facile synthesis of a nanoporous sea sponge architecture in a binary metal oxide

“…9f) delivers a specic capacitance of 76 F g À1 with an energy density of 75 W h kg À1 at a power density of 125 W kg À1 . The electrochemical performance of the binary metal oxide reported in this work compares well with similar materials reported in the literature like Co 3 O 4 (57 F g À1 ), 40 NiCo 2 O 4 (64 F g À1 ), 33 Co-Ni oxides (82 F g À1 ), 1 CoMoO 4 (25 F g À1 ), 41 NiMoO 4 (100 F g À1 ), 42 and other ternary metal oxides. 43 Furthermore, the device constructed using the binary metal oxide exhibited long-term stability, reproducing a similar linear charge-discharge curve aer 1000 cycles (Fig.…”

Nickel/Cobalt Molybdate Hollow Rods Induced by Structure and Defect Engineering as Exceptional Electrode Materials for Hybrid Supercapacitor

“… [47–49] More importantly, the Mo 3d peaks of D−H−NiMoO 4 @CoMoO 4 were positively shifted relative to H−NiMoO 4 @CoMoO 4 (Figure 3c), suggesting the formation of low oxidation states of molybdenum given the partial reduction of Mo 6+ and the incremental concentration of O‐defects [35,40,41] . Alongside the above, a peak at 531.2 eV (Figure 3d) was noted, which could be attributed to the O‐defect with a lower oxygen coordination, as well as a peak at 532.5 eV which reflects O−H, likely caused by the presence of surface‐absorbed water (2NaH 2 PO 2 ⋅H 2 O PH 3 (g)↑+Na 2 HPO 4 (s)+2H 2 O (g)↑) [36,40,50] . In comparison with D−H−NiMoO 4 @CoMoO 4 , the peak associated with O‐defect sites (531.2 eV) is evidently heightened in H−NiMoO 4 @CoMoO 4 (Figure 3e), demonstrating an incremental concentration of O‐defect sites after phosphating surface heat‐treatment [51] .…”

A Hybrid Electrochemical Energy Storage Device Using Sustainable Electrode Materials

“…The loss in capacity is mainly attributed to the diffusion‐controlled response and this is further degraded at higher sweep rates. The delivered stable capacitance of the fabricated hybrid device (95 F/g after 1000 cycles), which is compares favourably with that of similar materials reported for battery‐supercapacitor hybrid devices in the literature like Co 3 O 4 (57 F/g), NiCo 2 O 4 (64 F/g), Co – Ni oxides (82 F/g), CoMoO 4 (25 F/g), and NiMoO 4 (100 F/g), and other ternary metal oxides . Importantly, these reported materials have not used eggshell as anode.…”