A non-conventional way to modulate the capacitive process on carbon cloth by mechanical stretching

Abstract

This work investigates the in situ capacitive charging/discharging process of a carbon cloth surface under an external mechanical strain in order to understand the strain-modulated electrochemistry of an amorphous material. Our work first quantifies the electrochemical change in capacitive potential, E, in response to an applied linear strain, ε. The experimental data show that tensile strain could positively shift the capacitive potential. More importantly, the discharging time, a significant representative parameter of the energy storage performance of a material, is shortened when mechanically stretched. This phenomenon suggests that the specific capacitance is strain-dependent, and tensile strain decreases the specific capacitance of carbon cloth. This dependence could be attributed to a change in the surface free energy of carbon cloth when it is mechanically stretched. External mechanical work can modulate the typical capacitive process on not only metal or metal-oxide surfaces with specific lattice structures but also the surfaces of amorphous materials.