Periodic stacking of 2D charged sheets: Self-assembled superlattice of Ni–Al layered double hydroxide (LDH) and reduced graphene oxide

Abstract

Periodic Stacking of 2D Charged Sheets: Self-Assembled Superlattice of Ni-Al Layered Double Hydroxide (LDH) and Reduced Graphene Oxide, Nano Energy, http://dx. AbstractVertically stacked artificial 2D materials, such as van der Waals heterostructures, hold great scientific and technological promise. Stacking 2D atomic layers with stronger electrostatic forces in a controlled fashion could be more challenging. Positively charged atomic sheets of layered double hydroxide (LDH) such as hydrotalcite mineral with weakly bound anions have known intercalation and anion exchange properties, while reduced graphene oxide (rGO) are known to be negatively charged. So self-assembly of periodic (LDH/rGO) n superlattice is possible, although true periodicity at atomic scale has never been demonstrated for Ni-Al LDH. This work introduces a new protocol for the synthesis of true Ni-Al LDH / GO superlattice and the corresponding reduced product Ni-Al LDH/rGO, by systematically optimizing various key experimental parameters in chemical exfoliation, dispersion and self-assembly by co-feeding. This method is further applied to the successful synthesis of more complex Ni-Co-Al/GO superlattice. The Ni-Al LDH/rGO superlattice is then tested as cathode in alkaline hybrid supercapacitor, with 129 Ah/kg capacity at 8-min discharge, two times that of pristine Ni-Al LDH, and maintains 72.7 % of its initial capacity after 10,000 charge/discharge cycles. Our superlattice synthesis strategy and its energy applications demonstrate the potential to design artificial 2D materials.

Significant Role of Al in Ternary Layered Double Hydroxides for Enhancing Electrochemical Performance of Flexible Asymmetric Supercapacitor

“…As the power density increases to 6286 W kg −1 , the energy density still can be retained to a value of 22 Wh kg −1 . These energy and power density values compare favorably with most of the recently reported LDH supercapacitors, such as NiAl‐LDH/rGO//Active carbon (15.42 Wh kg −1 at 230 W kg −1 ), NiMn‐LDHs/PC‐1//Active carbon (18.6 Wh kg −1 at 225.03 W kg −1 ), Co x Ni 1− x ‐LDH/CN x @NGHSs (28.9 Wh kg −1 at 1875 W kg −1 ), NiCo‐LDH (41.46 Wh kg −1 at 212.68 W kg −1 ), NiCo‐LDH/NG (31.2 Wh kg −1 at 354 W kg −1 ), CoMn‐LDH//AC (5.9 Wh kg −1 at 1000 W kg −1 ), and CoNiFe‐LDH/CNFs (30.2 W h kg −1 at 800 W kg −1 ),10a shown in Figure f.…”

Recent Advances in Composites of Graphene and Layered Double Hydroxides for Water Remediation: A Review

“…The exfoliation/restacking methodw as investigated for the synthesis of G@LDH materials because of the electrostatic attraction between the LDH and Gc omponents. [53][54][55] The presence of surfacef unctional groups make GO negatively charged, whilst LDH is positively charged with replaceable anionic interlayer structures. [21,56] Huang et al fabricated compositeso fr GO and CoAl-LDH nanosheets (rGO/CAN-LDH-NS) by using the exfoliation/restacking method (Scheme 2A).…”

Removal of Anionic Dyes from Water using Polyethylene Glycol Modified Ni‐Al‐layered Double Hydroxide Nanocomposites

“…The metal oxide layers present in the LDH which permits interlayer spacing to accommodate anions for intercalation and the intercalated anions are balanced by adjacent layers of metal oxide in LDH this phenomenon is highly admirable for dye removal applications . Now‐a‐days researchers are endeavouring to synthesize LDH using various divalent metal ions isomorphously substituted . The other divalent substituted LDH structures are almost similar to mineral hydrotalcite.…”