Synthesis of Cubic Ni(OH)2 Nanocages Through Coordinating Etching and Precipitating Route for High-Performance Supercapacitors

Abstract

Rational design of cage-like structure is an effective method for the improvement of the capacitive performance of transition metal hydroxides. In this work, cubic Ni(OH)2 nanocages (Ni(OH)2 NCs) were constructed through a coordinating etching and precipitating (CEP) route. Ni(OH)2 NCs possess abundant active sites, sufficient diffusion channels, and accelerated electron transfer rate, which are beneficial for electrochemical kinetics. As a positive electrode for supercapacitors, the Ni(OH)2 NCs/Ni foam (NF) electrode presents a high specific capacitance of 539.8 F g−1 at 1 A g−1, which is much larger than that of broken Ni(OH)2 NCs/NF (Ni(OH)2 BNCs/NF, 87.3 F g−1 at 1 A g−1). In addition, the Ni(OH)2 NCs/NF electrode still retains 96.9% of its initial specific capacitance after 2000 cycles. The asymmetric supercapacitor (ASC) devices were assembled using Ni(OH)2 NCs/NF and activated carbon (AC)/NF as positive and negative electrodes, respectively. The ASC exhibits a higher energy density of 23.3 Wh kg−1 at a power density of 800 W kg−1 compared to Ni(OH)2 BNCs/NF (3 Wh kg−1 at 880 W kg−1). These results demonstrate that the Ni(OH)2 NCs/NF electrode presents potential applications in the field of energy storage. The design of cage-like structure paves an effective way to achieve high-performance electrode materials.Electronic supplementary materialThe online version of this article (10.1186/s11671-019-3096-6) contains supplementary material, which is available to authorized users.

Co/CoP Nanoparticles Encapsulated Within N, P-Doped Carbon Nanotubes on Nanoporous Metal-Organic Framework Nanosheets for Oxygen Reduction and Oxygen Evolution Reactions

“…The development of modern society depends on energy supply to a large extent, but with environmental problems induced by the burning of fossil fuels and the aggravation of energy shortage, it is necessary to find new conversion systems or renewable energy [1][2][3][4]. Fuel cells and metal-air batteries are considered to be promising energy systems; however, their poor energy conversion efficiency and short life span are the main bottlenecks that limit their widespread use [5][6][7][8][9].…”

Oxygen transport in Pr nickelates: Elucidation of atomic-scale features

“…One can see that for the fresh sample Ni is present in two states with binding energies (BE) of Ni2p 3/2 of 854.7 and 856.2 eV (Fig. 1(a)), which could be assigned to the Ni 2+ in Pr 1.6 Ca 0.4 NiO 4+δ and Ni 2+ in Ni(OH) 2 , respectively [6,54,55]. We believe that the latter state is more preferable than Ni 3+ in the composition of Ni 2 O 3 .…”

Mesoporous Cubic Nanocages Assembled by Coupled Monolayers With 100% Theoretical Capacity and Robust Cycling

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