In Situ Growth of Ultrathin NiO Nanosheet‐Arrays on MOF‐Derived Porous Co₃O₄ Scaffolds as High‐Performance Cathode for Asymmetric Supercapacitors

Abstract

The ever‐increasing market for portable and wearable electronic devices creates a demand for high‐efficiency electrochemical energy storage devices with excellent flexibility. Herein, MOF‐derived porous Co3O4 scaffolds as the core, ultrathin NiO nanosheet‐arrays as the shell, well‐aligned core‐shell structured Co3O4@NiO were constructed on carbon cloth (CC/Co3O4@NiO) via facile chemical bath methods. Composition, morphological structure, and electrochemical performance of the hybrid nanomaterials were analyzed in detail. Benefiting from the MOF‐derived porous Co3O4 core, the NiO shell with large specific surface area, and close conductive linkages between the core and shell, CC/Co3O4@NiO presents an outstanding areal capacitance of 3015.1 mF cm−2 (1206 F g−1) at 5 mA cm−2 and an exceptional rate performance. Additionally, the flexible SASC device assembled with the CC/Co3O4@NiO cathode possesses an ultra‐high volumetric energy density of 3.11 mWh cm−3 at a volumetric power density of 116 mW cm−3 with a satisfactory cycling stability (90.1 % of after 10000 cycles). These values are superior to the great majority of the state‐of‐the‐art flexible electrochemical capacitors. Thereby, the core‐shell structured CC/Co3O4@NiO is a promising candidate material for energy storage devices, and this work can provide a reference for the structural design and constructing of electrode materials.

Enhanced Electrochemical Performance of CuO Capsules@CDs Composites for Solid-State Hybrid Supercapacitor

“…These two values were greater than 0.5, indicating diffusion and capacitive-controlled electrochemical processes (Figure S4b). The capacitive and diffusive-controlled contributions were estimated by the following equation i v = k 1 v + k 2 v 1 / 2 where k 1 v is the surface-controlled current, k 2 v 1/2 is the diffusion-controlled current, and i v is the total current response of the CV curves. The linearly fitted slope of i / v 1/2 vs v 1/2 was used to calculate the k 1 and k 2 values.…”

Nickel oxide electrochromic films: mechanisms, preparation methods, and modification strategies–a review

“…Most researchers choose NH 3 ·H 2 O as a complexant regent to control the deposition rate in the preparation of NiO films. 43,58,132 Boo et al explored the effect of NH 3 ·H 2 O addition on the morphology and EC properties of NiO films deposited by CBD. They found that adding an appropriate amount of NH 3 ·H 2 O is important for achieving a balanced EC performance between Δ T and cyclic durability.…”

“…Due to the chemical reaction controlling the CBD process, it is generally necessary to add additives to the deposition solution to control the deposition rate and obtain a uniform film. Most researchers choose NH 3 ÁH 2 O as a complexant regent to control the deposition rate in the preparation of NiO films 43,58,132. Boo et al explored the effect of NH 3 ÁH 2 O addition on the morphology and EC properties of NiO films deposited by CBD.…”

3D net-like Co3O4@NiO nanostructures for high performance supercapacitors

“…27–32 However, the poor electrical conductivity and low utilization rate of NiO limit its application in the field of high-performance supercapacitors. 33–35…”