Atomic Modulation of 3D Conductive Frameworks Boost Performance of MnO2 for Coaxial Fiber-Shaped Supercapacitors

Abstract

Coaxial fiber-shaped supercapacitors are a promising class of energy storage devices requiring high performance for flexible and miniature electronic devices. Yet, they are still struggling from inferior energy density, which comes from the limited choices in materials and structure used. Here, Zn-doped CuO nanowires were designed as 3D framework for aligned distributing high mass loading of MnO2 nanosheets. Zn could be introduced into the CuO crystal lattice to tune the covalency character and thus improve charge transport. The Zn–CuO@MnO2 as positive electrode obtained superior performance without sacrificing its areal and gravimetric capacitances with the increasing of mass loading of MnO2 due to 3D Zn–CuO framework enabling efficient electron transport. A novel category of free-standing asymmetric coaxial fiber-shaped supercapacitor based on Zn0.11CuO@MnO2 core electrode possesses superior specific capacitance and enhanced cell potential window. This asymmetric coaxial structure provides superior performance including higher capacity and better stability under deformation because of sufficient contact between the electrodes and electrolyte. Based on these advantages, the as-prepared asymmetric coaxial fiber-shaped supercapacitor exhibits a high specific capacitance of 296.6 mF cm−2 and energy density of 133.47 μWh cm−2. In addition, its capacitance retention reaches 76.57% after bending 10,000 times, which demonstrates as-prepared device’s excellent flexibility and long-term cycling stability.

A Better Zn-Ion Storage Device: Recent Progress for Zn-Ion Hybrid Supercapacitors

“…Manganese oxides, with many outstanding properties like low cost, high theoretical capacity, tunable and multifarious crystal structure, etc., have been well investigated in various ESSs [185][186][187]. Among various manganese oxides, MnO 2 is one of the most promising manganese oxides.…”

3D Architecturing Strategy on the Utmost Carbon Nanotube Fiber for Ultra‐High Performance Fiber‐Shaped Supercapacitor

“…With the increasing demand for wearable intelligent devices in the modern flexible electronics market within the last couple of years, numerous researchers have focused on quasi‐1D fiber‐shaped supercapacitors (FSSCs) with the following characteristics: small volume, light weight, high performance, and durability from frequent distortion during use. [ 1–9 ] However, despite these numerous merits and academic research accomplishments, several key technical problems/challenges, including their electrochemical performance, mechanical flexibility, and cycling performance under various kinds of deformations, have not yet been resolved. [ 3,10,11 ] To faithfully translate laboratory‐level FSSCs into practical applications, the above issues must be addressed simultaneously.…”

Cauliflower-Like Ni/MXene-Bridged Fiber-Shaped Electrode for Flexible Microsupercapacitor

“…Wang et al fabricated Zn-CuO nanowires on a Cu wire as a framework for high mass loading of MnO 2 nanosheets, which showed a capacitance value of 2.2 Fcm −2 at 2 mAcm −2 . 17 Shahrokhian and Naderi reported a 3D porous Ni-Zn-P scaffold on Cu wire for loading CoNi 2 S 4 nanosheets that delivered a high volumetric capacitance of 889.68 Fcm −3 (8.9 Fcm −2 , 1.12 Fcm −1 ) at 4 mAcm −2 . 4 Moreover, 2D materials that have great electrical conductivity and specific surface area are good supporting materials for FSC substrates.…”