Facile synthesis of NiAl layered double hydroxide nanoplates for high-performance asymmetric supercapacitor

Abstract

Layered double hydroxide (LDH) is a promising electrode material for supercapacitor owing to its versatility in compositions, high theoretical capacitance, environmental benignity, and low cost. However, capacity fading of LDH hinders its application in energy storage. Herein, we develop a facile approach to synthesize NiAl-LDH nanoplates possessing high electrochemical activity and desirable morphology to improve ion diffusion kinetics and reduce charge transfer resistance, leading to enhanced specific capacitance compared to pristine NiAl-LDH. Scanning electron microscopy shows that the LDH nanoplates are as thin as ∼30 nm with a mean lateral dimension of ∼150 nm. The NiAl-LDH nanoplates electrode delivers remarkably high specific capacitance of 1713.2 F g−1 at 1 A g−1 and good cycling ability of 88% capacitance retention over 5000 cycles compared to only 757.1 F g−1 at 1 A g−1 and 76.4% of the pristine NiAl-LDH. An asymmetric supercapacitor (ASC) is assembled using NiAl-LDH nanoplates and graphene as positive and negative electrodes, respectively. The ASC operating at 1.4 V delivers a high specific capacitance of 125 F g−1 at 1 A g−1 with a high energy density of 34.1 Wh kg−1 at a power density of 700 W kg−1 and outstanding cyclic stability (91.8% capacitance retention after 5000 cycles)

A High‐Energy Aqueous Sodium‐Ion Capacitor with Nickel Hexacyanoferrate and Graphene Electrodes

“…Table S1 shows the comparative energy performance of the Ni‐HCF∥graphene capacitor device with the reported Na‐ion capacitors and asymmetric capacitors. The obtained energy density is higher compared to that of recent works on Mn‐HCF∥Fe 3 O 4 /rGO hybrid capacitor device (27.9 Wh kg −1 ), Na 2 CoSiO 4 ∥AC hybrid capacitor device (12.4 Wh Kg −1 ), PB∥AC hybrid capacitor device (30 Wh kg −1 ), NaMnO 2 ∥NaTi 2 (PO 4 ) 3 /C battery (30 Wh kg −1 ), and some of the asymmetric supercapacitors . The cyclic stability of the Ni‐HCF∥graphene sodium ion hybrid capacitor device (given in Figure (F)) shows nearly 91 % of capacitance retention over 2000 cycles of charge‐discharge which revealed superior cyclic stability of the device …”

Sulfidation of Hierarchical NiAl−LDH/Ni−MOF Composite for High‐Performance Supercapacitor

“…For NiAl‐LDH, the relatively weak diffraction peaks at 10.5°, 20.4°, 34.4° and 61.3° are index to (003), (006), (012), (110) plane, which is correspond to the crystal structure of the NiAl‐LDH (JCPDS No. 22‐0452) . The high intensity peak at 11.2° is characteristic peak of the crystal structure of Ni−MOF .…”

“…22-0452). [24] The high intensity peak at 11.2°is characteristic peak of the crystal structure of NiÀ MOF. [17] The patterns of NiAlÀ LDH, NiÀ MOF, NiAl-LDH-0.5/NiÀ MOF show obvious similarities, indicating that the samples probably have the same layered topology crystal structure.…”

“…[30] Furthermore, a week peak at 853.4 eV is the characteristic peak of Ni 2p 3/2 for Ni 3 S 2 of NiAl-LDH-0.5/NiÀ MOF/S10. [22a] The Al 2p spectrum displays a peak at 75.4 eV, suggesting the existence of Al 3 + [24,27] (Figure 6c). The S 2p spectrum (Figure 6d) displays the peaks at 161.4 (metal-sulfur bonds) and 162.6 eV (sulfur ions at low coordination ordinarily) belonging to S 2p 1/2 and 2p 3/2 , respectively.…”

Recent Advances of Two‐Dimensional Nanomaterials for Electrochemical Capacitors

“…Cho et al. reported a facile hydrothermal approach to synthesize distinct hexagonal Ni−Al LDH nanoplates with a mean lateral dimension of 150 nm and the thickness of about 30 nm . As an electrode material for ECs, the platelike structure is favorable for increasing the number of accessible reaction sites for the redox reaction and decreasing the ion‐diffusion pathways, and thus, enhancing the specific capacitance.…”