Fabrication of Oxygen‐Vacancy Abundant NiMn‐Layered Double Hydroxides for Ultrahigh Capacity Supercapacitors

Abstract

The rational design of advanced structures consisting of multiple components with excellent electrochemical capacitive properties is one of the crucial hindrances to be overcome for high‐performance supercapacitors (SCs). Herein, a superfast and facile synthesis of flower‐like NiMn‐layered double hydroxides (NiMn‐LDH) with high SC performance using an electrodeposition process on nickel foam is proposed. Oxygen vacancies are then modulated via mild H2O2 treatment for the first time, significantly promoting the electrochemical energy storage performance. The oxygen‐vacancy abundant NiMn‐LDH (Ov‐LDH) reaches a maximum specific capacity of 1183 C g−1 at the current density of 1 A g−1 and retains a high capacity retention of 835 C g−1 even at a current density of up to 10 A g−1. Furthermore, the assembled asymmetric SC device achieves a high specific energy density of 46.7 Wh kg−1 at a power density of 1.7 kW kg−1. Oxygen vacancies are proven to play a vital role in the improvement of electrochemistry performance of LDH based on experimental and theoretical studies. This vacancy engineering strategy provides a new insight into SC active materials and should be beneficial for the design of the next generation of energy storage devices.

Chemical Modifications of Layered Double Hydroxides in the Supercapacitor

“…To date, there has been much research on doping to improve the pseudocapacitance performance of LDHs. Gao et al [13] prepared NiCoAl LDH on carbon cloth, introducing different amounts of Al in the NiCo-OH (nickel cobalt hydroxide) ( Figure 9a-c). The morphology of the NiCo-OH changed from nanowires to nanosheets after the Al element was introduced.…”

“…The SEM images of a) NiCo-OH and b) NiCoAl LDH on carbon cloth, c) the XRD patterns of NiCo-OH and NiCo LDH with different amounts of Al. [13] Copyright 2019, John Wiley & Sons, Inc. The SEM images of d) ZnNiCo LDH and e) NiCo LDH, f) the XRD pattern of NiCo LDH and ZnNiCo LDH, g) the cycling stability of NiCo LDH and ZnNiCo LDH with different amounts of Zn.…”

“…The current research has reported many successful methods to prepare the oxygen vacancy of transition metal oxides such as Co 3 O 4 , [ 73 ] MnO 2 , [ 74 ] and NiCo 2 O 4 , [ 75 ] which provides great inspiration for the construction of oxygen vacancy in LDHs. Recently, Zou et al [ 12 ] prepared oxygen vacancy NiMn LDH (Ov‐NiMn LDH) using in situ H 2 O 2 oxidation ( Figure a–f). The rise of the valence state from Mn 2+ to Mn 3+ and Mn 4+ leads to charge imbalance in the host layer of the NiMn LDH, thereby leading to the formation of oxygen vacancy.…”

Oxygen‐vacancy‐rich hydrated bimetallic chloride for supercapacitor cathode with remarkable enhanced performance

“… 29 Figure S2a shows the survey spectrum of six electrodes, from which can be seen the Ni, V, Cl and O elements in the materials. For the XPS spectrum of O 1s in Figures 4B and S2b, there four deconvolute peaks can be fitted 30,31 . Concretely, the peak at about 529.7 eV could be contributed by metal‐oxygen bond, the peak at about 530.9 eV originate from hydroxyl (O OH ), the peak located at about 531.8 eV is contributed to oxygen vacancy sites with low oxygen coordination and the peak at 533.1 eV is arisen from adsorbed molecular water, respectively.…”

Engineering Layered Double Hydroxide–Based Photocatalysts Toward Artificial Photosynthesis: State‐of‐the‐Art Progress and Prospects

“…However, there is a tradeoff between the quantity of unsaturated Zn sites and the performance for photocatalytic energy application. [ 88 ] Other common methods for the oxygen vacancy engineering of LDH catalysts are with plasma etching, [ 89 ] oxidizing agents, [ 90 ] flame treatment, [ 3 ] and exfoliation of ultrathin LDH sheets. [ 91 ] In an attempt to produce sub‐3 nm LDH particles, monolayer LDH nanosheet precursors in formamide were ultrasonicated to obtain a high yield of ultrafine LDH (LDH‐UF) samples.…”