Controllable Synthesis of NiCo LDH Nanosheets for Fabrication of High‐Performance Supercapacitor Electrodes

Abstract

A unipolar pulse electrodeposition method was employed to controllably synthesize nanosheet type NiCo LDH. The effect of concentration rate of Ni(NO3)2/Co(NO3)2 preparation solution on crystalline structure, morphology and supercapacitive performance was investigated systematically. Experimental found that the morphology and composition of NiCo LDH was highly depend on the Ni2+/Co2+ molar ratios of preparation solution; and the obtained Ni0.76Co0.24 LDH materials showed small nanosheet size and uniform distribution on carbon fiber electrode. Ni0.76Co0.24 LDH electrode was evaluated for supercapacitor application, which revealed a high specific capacitances of 2189.8 and 1908.8 F g−1 at the current density of 1 and 30 A g−1 respectively and a good cycle stability, retaining 70.3 % of the initial capacitance after 20000 charge and discharge cycles at 50 A g−1. Moreover, the Ni0.76Co0.24 LDH electrode exhibits a high energy density of 76 Wh Kg−1 at a power density of 250 W Kg−1 and a high power density of 7500 W Kg−1 at energy density of 66 Wh Kg−1. The as‐prepared Ni0.76Co0.24 LDH as positive electrode for asymmetric supercapacitor exhibits excellent energy density of 4.1 Wh Kg‐1 at a power density of 4000 W Kg‐1

NiMoCo layered double hydroxides for electrocatalyst and supercapacitor electrode

“…8f. A maximum energy density of 141 W h kg −1 at a power density of 2695 W kg −1 is obtained, which are superior to some previous reports [45][46][47][48][49][50].…”

NiCo-LDH/Ti3C2 MXene hybrid materials for lithium ion battery with high-rate capability and long cycle life

“…Hence, a single-layer p(2 × 2) unit cells of NiCo-LDH was constructed with a 20 Å vacuum along the vertical direction to avoid the interactions between the periodic images. Taking Co(OH) 2 as an example, to analyze lithium ion intercalation-deintercalation process more deeply, the interaction energy E i as well as the theoretical capacities were carefully examined, as illustrated in Fig. 7 (a).…”

“…The layered double hydroxide (LDH) is an inorganic layered material that has been known for over 150 years [1] . The general formula of LDH should be represented as M 2 + 1-x M 3 + x (OH) 2 An − x / n •m H 2 O [2] . The anion exchange and the structure remains unchanged while changing its own metal cations properties [3] , could make LDHs wide applications in the fields of catalysis [4] , biology [5] , energy conversion and storage [6] .…”

Supercapacitor Performance of Nickel-Cobalt Sulfide Nanotubes Decorated Using Ni Co-Layered Double Hydroxide Nanosheets Grown in Situ on Ni Foam

“…As a result, the superior super-capacitive performance of the NCS@NCOH//AC device originates from the following characteristics: (1) The NCS nanosheets enhance the interfacial contact between the electrolyte and the active materials, and they provide abundant active sites for the energy storage properties; (2) the AC@NF negative electrode facilitates ion transport and electrolyte accessibility, leading to a lower resistance. From our experimental achievements, it can be stated that we obtained better results compared to the other reported nickel-cobalt sulfide-based ASCs such as NCS//C ASCs (22.8 Whkg −1 at 160 Wkg −1 ) [30], Co 3 O 4 @MnO 2 //MEGO (17.7 Whkg −1 at 158 Wkg −1 ), PNTs@NCS//PNTs@NCS ASCs (21.3 Whkg −1 at 417 Wkg −1 ) [31], NCS@HGH//NCS@HGH ASCs (21.3 Whkg −1 at 2100 Wkg −1 ) [32], Ni 3 S 2 /MWCNT-NC//AC ASCs (19.8 Whkg −1 at 798 Wkg −1 ) [33], and NiCo LDH//AC ASCs (15.9 Whkg −1 at 400 Wkg −1 ) [34]. Figure 12 shows the Ragone plots of the NCS@NCOH//AC asymmetric supercapacitors attained from the GCD measurements at various CDs.…”

“…Furthermore, following Equations (4) and (5), it can be seen that the NCS@NCOH//AC asymmetric supercapacitor achieves a maximum energy density of electrolyte accessibility, leading to a lower resistance. From our experimental achievements, it can be stated that we obtained better results compared to the other reported nickel-cobalt sulfide-based ASCs such as NCS//C ASCs (22.8 Whkg -1 at 160 Wkg -1 ) [30], Co3O4@MnO2//MEGO (17.7 Whkg -1 at 158 Wkg -1 ), PNTs@NCS//PNTs@NCS ASCs (21.3 Whkg -1 at 417 Wkg -1 ) [31], NCS@HGH//NCS@HGH ASCs (21.3 Whkg -1 at 2100 Wkg -1 ) [32], Ni3S2/MWCNT-NC//AC ASCs (19.8 Whkg -1 at 798 Wkg -1 ) [33], and NiCo LDH//AC ASCs (15.9 Whkg -1 at 400 Wkg -1 ) [34]. Figure 12.…”