Piezo-electrochemical effect in lithium-intercalated carbon fibres

Abstract

In this paper we have conducted experiments to investigate the coupling between electrochemical and mechanical properties of lithium (Li)-intercalating carbon fibres (CFs). The results show promising potential for new functionalities of CFs for electrochemical actuation, sensing and energy harvesting. Li-intercalation at 1C-rate in CFs subjected to a constant tensile extension induced a free reversible longitudinal expansion strain of approximately 0.30% which can be used as mechanical actuation. Varying the tensile extension of lithiated CFs resulted in a piezoelectric response of the open-circuit potential, in the range of several mV, enabling strain sensing. If the electrical potential is kept constant during a tensile extension a piezo-electrochemical current response is found with about 50% mechanical to electrical energy conversion efficiency, enabling energy harvesting.