Electrochemical Deposition Enables Freestanding CoNi Layered Double Hydroxide/MnO_X Electrode with Enhanced Electrochemical Properties for Asymmetric Supercapacitors

Abstract

A carbon fiber paper (CFP)‐supported CoNi layered double hydroxide (LDH)/MnOX or MnOX nanomaterial is prepared by a simple and effective two‐step electrochemical deposition process. The binder‐free CoNi LDH/MnOX/CFP exhibits enhanced electrochemical properties than that of MnOX/CFP, with a maximum capacitance of 1460 F g−1 at 1 A g−1, and an excellent capacitance retention of 87% at 4 A g−1. Notably, the CoNi LDH/MnOX composite exhibits a remarkable cycling stability with 82% capacitance retention over 20 000 cycles even at a high current density of 32 A g−1. The outstanding electrochemical performance of the CoNi LDH/MnOX/CFP can contribute to the synergistic effects of the freestanding electrode with improved electrical conductivity, electrochemical activity, and material utilization than pure MnOX. Furthermore, an asymmetric supercapacitor (ASC) fabricated with a CoNi LDH/MnOX/CFP positive electrode and active carbon (AC)/CFP negative electrode displays a high energy density of 28.1 Wh kg−1 at a power density of 400 W kg−1. These encouraging results indicate that the low‐cost CoNi LDH/MnOX/CFP composite shows great potential for high‐performance energy storage applications.

Synergistically Driven CoCr-LDH@VNiS2 as a Bifunctional Electrocatalyst for Overall Water Splitting and Flexible Supercapacitors

“…The energy density and power density are the most important parameters to evaluate the performance of the ASC device. 29,30 Figure 7h indicates the Ragone plots demonstrate the maximum energy density of 96.03 W h kg −1 at a power density of 539.98 W kg −1 , which is superior compared to the previously reported ASC devices such as CoO@CoAl-LDH, 31 CoNi LDH/MnOX, 32 NiCoP@NiFe-LDH, 33 NiZn-LDH@ NiCoSe 2 , 34 Co-NiS/NCDs, 35 and Co-MOF@CoCr 2 O 4 . 36 The long-term cyclic stability of the CoCr-LDH@VNiS 2 ASC device is illustrated in Figure 7i.…”

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

“…[ 1,21–25 ] The performance of recently reported LDHs and their hybrids as HSC cathodes are summarized, as shown in Figure . [ 21–39 ]…”

Efficient Flexible All-Solid Supercapacitors with Direct Sputter-Grown Needle-Like Mn/MnOx@Graphite-Foil Electrodes and PPC-Embedded Ionic Electrolytes

“…Hence, there is a focus on alternative TMOs electrode materials, especially abundant manganese oxide (MnO x ) and its composites, due to its eco-friendliness, low cost and high charge storage capabilities, but the increase in the stable potential window to enhance the energy density of the SC is still under debate. Recent studies with MnO x report relatively low potential windows: The MnO x /Au-based, all-solid-state microsupercapacitor of Si et al [ 23 ] shows a potential window of only 1.0 V, while Tian et al prepared a carbon fiber paper-supported Co/Ni-layered double hydroxide MnO x electrode by a simple two-step electrochemical deposition process for asymmetric supercapacitor (ASC) application exhibiting a potential window of 1.6 V [ 24 ]. Reduced graphene Oxide (RGO)-mediated synthesis of Mn 3 O 4 electrode for ASC by Gao et al also results in a potential window of 1.6 V [ 25 ].…”