Electrochemical Behavior of Nanoporous Gold/Polypyrrole Supercapacitor under Deformation.

Due to the high demand of wearable electronics, flexible supercapacitors have been extensively developed in recent years. Yet, the effect of deformation in the interior electrode material suffered in practical applications on the performance received less attention. Here, we study the electrochemical behavior of macroscopic nanoporous gold/polypyrrole (NPG/PPy) in situ under compression deformation. Dealloying-driven NPG, a network constructed by bi-continuous nano-scaled ligaments and pores, can serve as a compression-tolerant substrate for PPy supercapacitor material. The electrochemical capacitance of NPG/PPy subjected to compression deformation is revealed to decrease at the scan rates and discharge current densities applied in this work. At the same time, the charge transfer resistance of NPG/PPy is found to increase. This electrochemical behavior is due to the locally reduced mass transport of electrolyte caused by the formation of new connections between the neighboring ligaments under the application of compression loads. The fundamental understanding of the effect of deformation on the performance of energy storage materials revealed in this study paves the way for their practical application in wearable devices.