Research Progress of NiMn Layered Double Hydroxides for Supercapacitors: A Review

Abstract

The research on supercapacitors has been attractive due to their large power density, fast charge/discharge speed and long lifespan. The electrode materials for supercapacitors are thus intensively investigated to improve the electrochemical performances. Various transition metal layered double hydroxides (LDHs) with a hydrotalcite-like structure have been developed to be promising electrode materials. Earth-abundant metal hydroxides are very suitable electrode materials due to the low cost and high specific capacity. This is a review paper on NiMn LDHs for supercapacitor application. We focus particularly on the recent published papers using NiMn LDHs as electrode materials for supercapacitors. The preparation methods for NiMn LDHs are introduced first. Then, the structural design and chemical modification of NiMn LDH materials, as well as the composites and films derived from NiMn LDHs are discussed. These approaches are proven to be effective to enhance the performance of supercapacitor. Finally, the reports related to NiMn LDH-based asymmetric supercapacitors are summarized. A brief discussion of the future development of NiMn LDHs is also provided.

Nickel‐Based Transition Metal Nitride Electrocatalysts for the Oxygen Evolution Reaction

“…The intercalated anions are typical carbonates (CO 3 2À ), but can be simplys ubstituted by other anions( e.g.,N O 3À ,S O 4 2À ,C l À , Br À ). NiFe LDH, [65][66][67] NiMn LDH, [17,25] and NiCo LDH, [16,17] have been studied for OER, but main problem associated with Ni-based LDHs is their low conductivity (Ni 3 Fe LDH:1 .943 Scm; Ni 3 Fe LDHÀNH 3 :3 .759 Scm; Ni 3 Fe LDHÀAr:3 .061 Scm), which is ag eneral dilemma with hydroxides. NiFe LDH, [65][66][67] NiMn LDH, [17,25] and NiCo LDH, [16,17] have been studied for OER, but main problem associated with Ni-based LDHs is their low conductivity (Ni 3 Fe LDH:1 .943 Scm; Ni 3 Fe LDHÀNH 3 :3 .759 Scm; Ni 3 Fe LDHÀAr:3 .061 Scm), which is ag eneral dilemma with hydroxides.…”

“…[17] Consequently,L DHs have gained attention for electrochemicalr eactions, they are capable of participating in anion exchange with the electrolyte. NiFe LDH, [65][66][67] NiMn LDH, [17,25] and NiCo LDH, [16,17] have been studied for OER, but main problem associated with Ni-based LDHs is their low conductivity (Ni 3 Fe LDH:1 .943 Scm; Ni 3 Fe LDHÀNH 3 :3 .759 Scm; Ni 3 Fe LDHÀAr:3 .061 Scm), which is ag eneral dilemma with hydroxides. [68] This obstacle can be resolved by either directly growing LDH on ac onductive substrate, such as carbon cloth, carbon nanotubes, carbon quantum dots, graphene, or Ni foam, or by hybridizing with ac onductive material.…”

“…These structures vary in composition and include nickel hydroxides, [21] nickel oxides, [13-15, 22, 23] nickel oxyhydroxides, [24] Ni-based layered double hydroxides, [16,17,25] and nickel sulfides. These structures vary in composition and include nickel hydroxides, [21] nickel oxides, [13-15, 22, 23] nickel oxyhydroxides, [24] Ni-based layered double hydroxides, [16,17,25] and nickel sulfides.…”

“…To date, many efforts have been dedicated to studyingt he OER properties of Ni-based compounds. These structures vary in composition and include nickel hydroxides, [21] nickel oxides, [13-15, 22, 23] nickel oxyhydroxides, [24] Ni-based layered double hydroxides, [16,17,25] and nickel sulfides. [26] These catalysts have been explored both in bulk and as nanostructures.…”

Use of Co/Fe-Mixed Oxides as Heterogeneous Catalysts in Obtaining Biodiesel

“…Layered double hydroxides can be prepared by different methods such as coprecipitation, hydrolysis with urea, sol-gel, hydrothermal treatment, combustion and mechanical synthesis, among others, with the most common and economic method being coprecipitation [23][24][25]. Studies have reported that the synthesis method, the conditions of synthesis, the type of cations and structural anions, the metal precursors and the metal ratio M 2+ /M 3+ are determining factors on the properties and applications of LDH [26][27][28][29]. An important element to improve the catalytic activity of LDH is the thermal treatment to form mixed spinel-type oxides, specifically in the production of biodiesel by heterogeneous catalysis [30,31].…”