Exploring the Potential of Multifunctional Carbon Fiber Composites
Topic(s) : Special Sessions
Co-authors :
Alfredo BICI (SWEDEN), Elvira LIND (SWEDEN), Dan ZENKERT (SWEDEN), Göran LINDBERGHAbstract :
Designing materials with multiple functionalities represents an effective weight optimization strategy in various industries. Carbon fibers have been proven to be a versatile lightweight material due to their excellent specific mechanical properties and their ability to intercalate lithium within their structure.
This study focuses on the development and characterization of a multifunctional carbon fiber laminate capable not only of carrying mechanical loads but also of morphing its shape in a cantilever setup, storing and harvesting energy, and functioning as a strain sensor. All these functions have been shown to work separately, whereas the integration of all functions into a single device remains unexplored.
The multifunctional laminate is composed of several components, including an aluminum foil coated with lithium iron phosphate (LFP) and layers of carbon fibers. Additionally, a bicontinuous structural electrolyte is used to embed the laminate which allows load transfer between the fibers and provides ionic conductivity.
The LFP layer serves as the lithium source in the device and acts as the positive electrode in a typical commercial lithium-ion battery. The application of a voltage difference between the LFP and one carbon fiber layer induces the migration of lithium ions toward the structure of the fibers, where they are stored. The lithium intercalation in the structure of the fibers causes a longitudinal expansion. This process is exploited to change the shape of the laminate by controlling the amount of lithium in each layer.
Furthermore, lithiated carbon fibers exhibit a piezo-electrochemical transducer (PECT) effect, which is a coupling between the mechanical and electrochemical properties of the material. This principle forms the basis of energy harvesting and strain sensing. By deforming the laminate, a voltage difference is generated that can either be used to power an external load or to determine the strain of the carbon fibers.
Mechanical testing and electrochemical cycling are used to characterize the performance of the laminate. In the design of a multifunctional laminate, a reduction in the individual performance compared to single-function products is expected. This trade-off is a consequence of accommodating multiple functionalities within a single device. However, it is crucial to acknowledge that this trade-off also paves the way for pursuing more complex designs, which could potentially yield significant weight savings benefits.
This study focuses on the development and characterization of a multifunctional carbon fiber laminate capable not only of carrying mechanical loads but also of morphing its shape in a cantilever setup, storing and harvesting energy, and functioning as a strain sensor. All these functions have been shown to work separately, whereas the integration of all functions into a single device remains unexplored.
The multifunctional laminate is composed of several components, including an aluminum foil coated with lithium iron phosphate (LFP) and layers of carbon fibers. Additionally, a bicontinuous structural electrolyte is used to embed the laminate which allows load transfer between the fibers and provides ionic conductivity.
The LFP layer serves as the lithium source in the device and acts as the positive electrode in a typical commercial lithium-ion battery. The application of a voltage difference between the LFP and one carbon fiber layer induces the migration of lithium ions toward the structure of the fibers, where they are stored. The lithium intercalation in the structure of the fibers causes a longitudinal expansion. This process is exploited to change the shape of the laminate by controlling the amount of lithium in each layer.
Furthermore, lithiated carbon fibers exhibit a piezo-electrochemical transducer (PECT) effect, which is a coupling between the mechanical and electrochemical properties of the material. This principle forms the basis of energy harvesting and strain sensing. By deforming the laminate, a voltage difference is generated that can either be used to power an external load or to determine the strain of the carbon fibers.
Mechanical testing and electrochemical cycling are used to characterize the performance of the laminate. In the design of a multifunctional laminate, a reduction in the individual performance compared to single-function products is expected. This trade-off is a consequence of accommodating multiple functionalities within a single device. However, it is crucial to acknowledge that this trade-off also paves the way for pursuing more complex designs, which could potentially yield significant weight savings benefits.