Mesoporous Nanohybrids of 2D Ni‐Cr‐Layered Double Hydroxide Nanosheets Pillared with Polyoxovanadate Anions for High‐Performance Hybrid Supercapacitor

Abstract

In this study, the use of exfoliation‐restacking strategy to prepare mesoporous nanohybrids of 2D Nickel‐chromium‐layered double hydroxide (Ni‐Cr‐LDH) nanosheets pillared with polyoxovanadate (POV) anions (Ni‐Cr‐LDH‐POV) for a high‐performance hybrid supercapacitor (HSC) is demonstrated. The pillaring approach of Ni‐Cr‐LDH monolayers with POV anions via exfoliation‐restacking strategy yields mesoporous ordered layered structure with a high surface area and interconnected network morphology. The pillared hybridization of Ni‐Cr‐LDH with POV anions boosts the electrochemical performance of the pristine Ni‐Cr‐LDH, which is attributed to the development of layer‐by‐layer stacking structure with expanded gallery height and high surface area interconnected network morphology. The Ni‐Cr‐LDH‐POV nanohybrid electrode exhibits an improved specific capacity of 294.5 mAh g−1 as compared to pristine Ni‐Cr‐LDH electrode (98.9 mAh g−1) at 1 mA cm−2 with 82% capacity retention after 5000 charge‐discharge cycles. A full‐cell HSC composed of mesoporous Ni‐Cr‐LDH‐POV nanohybrid as a cathode and reduced graphene oxide (rGO) as an anode delivers a maximum specific energy of 57.78 Wh kg−1 and specific power of 1.59 kW kg−1 with 87% cyclic durability over 10 000 charge‐discharge cycles. The present study demonstrates the usefulness of the pillared Ni‐Cr‐LDH‐POV nanohybrids via exfoliation‐restacking strategy for exploring high‐performance HSC.

Construction of a 2D/2D g-C3N5/NiCr-LDH Heterostructure to Boost the Green Ammonia Production Rate under Visible Light Illumination

“…The morphology of CN-5 and NC-L shown in Figure S3 confirms the 2D character of both CN-5 and NC-L. The morphology of NC-L is similar to that reported in a recently published study, which confirms the 2D structure . The TEM images of CN-NCL-2 are shown in Figure a,b, which further confirm the presence of the g-C 3 N 5 nanosheet decorated with NiCr-LDH.…”

“…Peaks in the range of 890–1690 cm –1 are assigned to the stretching modes of the CN heterocycles . The strong peak at 1365 cm –1 in NC-L is attributed to the bending vibrations of intercalated NO 3 – ions . A carbon dioxide absorption peak at ∼2300 cm –1 is also observed .…”

“…52 The strong peak at 1365 cm −1 in NC-L is attributed to the bending vibrations of intercalated NO 3 − ions. 53 A carbon dioxide absorption peak at ∼2300 cm −1 is also observed. 54 In the case of the heterostructures, all the characteristic peaks of CN-5 and NC-L are detected with a very small shift.…”

“…The morphology of NC-L is similar to that reported in a recently published study, which confirms the 2D structure. 57 The TEM images of CN-NCL-2 are shown in Figure 2a In the case of the N 1s spectrum, it can be fitted into three peaks at the binding energies of 401.63, 399.9, and 398.6 eV, which correspond to the −NH x , tertiary N, and C−N�C− bonds, respectively (Figure 3b). 58 For the heterostructure CN-NCL-2, significant shifts were observed in the case of C 1s and N 1s as compared to CN-5 shown in Figure 3a,b.…”

Graphene-Based Aqueous Magnesium Ion Hybrid Supercapacitors with an Appealing Energy Density Advanced by a KI Additive

“…16,30 Several reports showed that the capacitance relies on a compatibility between the pore size and the ion size. 30,31 Furthermore, the multivalent nature and the small atomic radius help to achieve extra capacitance. Graphene has a small pore size of ∼4.96 nm, which offers a short diffusion length for charge transportation with a low resistance.…”