Flexible and ultralong-life cuprous oxide microsphere-nanosheets with superior pseudocapacitive properties

Abstract

Nanostructured transition metal oxides have been investigated extensively for supercapacitor electrodes due to their high theoretical specific capacitance, low-cost, environment benignity and abundance.However, pristine transition metal oxides suffer from difficulty of synthesis, poor electronic conductivity and mechanical flexibility. In this work, we report a facile, low-cost and high-throughput synthesis of hierarchical structure which consists of cuprous oxide (Cu 2 O) microsphere-nanosheets on the surface of flexible Cu foil (namely Cu 2 O@Cu) via a two-step electrochemical method (anodization and electrooxidation). The influence of the anodization parameters on surface roughness of Cu foil has been investigated, and the optimum anodization procedure was determined to be 50 V for 4 cycles. This Cu 2 O@Cu electrode exhibits excellent capacitance properties, such as up to 390.9 mF cm À2 at 2 mA cm À2 in areal capacitance, and high flexibility, as observed by cyclic voltammetry measurement under various deformation (bending and folding) situations. Furthermore, the Cu 2 O@Cu electrode presents superior long-term cycling stability over 100 000 cycles, with the capacitance retention of over 80%.The present binder-free Cu 2 O@Cu microsphere-nanosheets electrode is highly promising for future applications in flexible supercapacitors.

Self‐Integrated Porous Leaf‐like CuO Nanoplate Array‐Based Anodes for High‐Performance Lithium‐Ion Batteries

“…In this regard, the design and exploitation of additive‐free self‐integrated LIB anodes are considered as an effective method to significantly enhance the battery performance. Hitherto, many effective approaches, including vacuum filtration, chemical vapor deposition and electrochemical oxidation have been reported . Yuan et al.…”

Improved Electrochemical Behavior of Amorphous Carbon-Coated Copper/CNT Composites as Negative Electrode Material and Their Energy Storage Mechanism

“…22 However, most of them -in particular copper -were not investigated in electrochemical capacitors except for a few reports on copperinfiltrated carbonized wood monoliths, 23 cuprous oxide microspherenanosheets, 24 copper-coating of activated carbon used as electrode material in a Li-ion capacitor, 25 copper-doped metal oxides 26 and copper as substrate 27 demonstrating electrochemical activity of copper in alkaline electrolyte solution. Furthermore, copper is a promising candidate electrode material for high power energy storage because of its high conductivity and environmental compatibility.…”

Facile Synthesis of Hierarchical CuO Nanoflower for Supercapacitor Electrodes

“…20 First, the completely clean and dried CuO@Cu electrode was weighed, then it was immersed into a 0.1-M hydrochloric acid solution for about 10 min with ultrasonic shaking until no obvious color change occurred. Next, the CuO nanostructures in the Cu foil surface were complete dissolved in the hydrochloric acid solution, and the Cu substrate was weighed again after being taken out of the solution, washed with distilled water and completely dried.…”

“…17 Fortunately, transition-metal oxides possess multiple oxidation states that enable rich redox reactions for pseudocapacitance generation, which can provide higher specific capacitance and energy density than that delivered by carbon-based active materials, and better cycling stability than conductive polymer materials. 20 However, the low conductivity of transition-metal oxides dramatically limits their wide application. To tackle this problem, two main strategies have been devised: (1) combining metal oxides with a conductive substance, which can enhance charge transport in electrodes 20 ; and (2) developing nanostructured electrodes, which show a high surface area for sufficient contact between the active materials and the electrolyte, but also provide a short diffusion path for ion/electron transfer.…”