3D nanostructured CuxO modified copper foam as a binder-free electrode for all-solid-state supercapacitor

Copper oxides (CuxO) play an active role in the field of binder-free electrodes for supercapacitors due to their own advantages, including high theoretical capacity, non-toxicity, low cost, etc. Developing mild and cheap process to prepare CuxO nanomaterials would broad its application in supercapacitors. In this paper, copper oxide is used as an active material and copper foam (CF) is chosen as a substrate to synthesize metal oxide-based electrodes by an in-situ oxidation method. Ingeniously, the availability of copper foam has a dual nature encompassing as a collector as well as a copper source. The as-obtained CuxO/CF-60 electrode possesses an area capacitance of 354.6 mF cm(-2) under 2 mA cm(-2). It also has superior cycle stability with 93.8 % of initial capacitance undergo 5000 charge-discharge cycles. Moreover, the all-solid-state asymmetric supercapacitor, combining CuxO/CF-60 and activated carbon (AC) pasted on nickel foam (NF) as the respective positive and negative electrodes, exhibits an energy density of 25 mu Wh cm(-2) when power density reaches 3 mW cm(-2). The CuxO/CF-60//AC/NF device displays better cycling stability as 80.2 % of initial capacitance after 5000 cycles. This work provides a simple way for designing CuxO based electrodes and lays the foundation for subsequent improvements in electrochemical performance.

Automated summary

This study explores the use of copper oxide and copper foam to prepare metal oxide-based electrodes for supercapacitors, demonstrating high performance and cycling stability. Additionally, the all-solid-state asymmetric supercapacitor, incorporating activated carbon and nickel foam, shows excellent energy density and cycling stability. This work provides a simple approach for designing Cu2O-based electrodes and lays the groundwork for future improvements in electrochemical performance.