Enhancing Electrochemical and Mechanical Properties of Solid Structural Battery Composites through the Modification of Polymer Electrolyte Chemistry and Patterning of Electrode-Electrolyte Interface
Topic(s) : Material science
Co-authors :
Mohammad ZAKERTABRIZI (UNITED STATES), Ehsan HOSSEINI , Myunghwan JEONG , Homero CASTANEDA-LOPEZ , Dorrin JARRAHBASHI , Amir ASADI (UNITED STATES)Abstract :
1. Introduction
Given the robustness of the carbon fiber and its high conductivity given its carbon backbone, it has already established its potential for use as negative electrode or collector. While the mechanical properties of the manufactured battery were impressive, the electrochemical performance left so much to be desired. Since then, optimizing the balance between loadbearing capability and electrochemical performance has been the goal of the ongoing research. We have strived to remedy this problem and improve upon the tailored manufacturing process through producing a completely novel form of epoxy to encompass the carbon fibers, providing a significant boost to its conductivity as the solid electrolyte. This novel form of epoxy was supplemented by a new tailorable approach of manufacturing cathode through a modifiable spray system.
2. Fully Solid Epoxy Electrolyte
We eliminate this trade-off by establishing a new framework where reactions between liquid electrolyte and polymer species during the curing process can boost both ionic conductivity and retain the mechanical prowess of the epoxy polymer base. We have developed a solid epoxy electrolyte capable of ion transfer in a desiccated state, achieved through a polymer chain and small cluster molecules facilitating the hopping process between polymer chains. This allows changing the ion transfer mechanism from dominant segmental motion above glass transition temperature (Tg) to ion hopping at room temperature much blow Tg. A brief overview of the results is brought in Fig. 1, and compared to the other notable studies in this area. In contrast to the state-of-the-art studies, where incorporating large contents of lithium salt within the epoxy deteriorates the polymer structure, our preliminary results show that the altered chemistry of the epoxy retains a significant portion of its original strength despite the salt content.
3. Patterned Electrode-Electrolyte Interface
Manufacturing a superior electrolyte is only one side of the coin. To use this potential to the greatest extent, creating a seamless cathode-electrolyte remains crucial. We use an in-house supercritical CO2 spray technique to tailor the post-evaporation patterns through changing the ratio of the materials within the droplets. Used as the main supplier of the electrons, lithium iron phosphate (LFP) was mixed with graphene nanoplatelets (GNP) to facilitate the flow of ions within the cell. Our experiments show that shifting the ratio of these materials within the droplets can create a dome or ring post-evaporation patterns that affects the capacity/power balance of cathode, and by extension the battery. The deposited patterns on carbon fibers showed that shifting from ring to dome increases the energy density by 35% in a cell with LiPF6 electrolyte and Li anode. These promising results show the potential of patterning to regulate the electrochemical properties of the manufactured battery.
Given the robustness of the carbon fiber and its high conductivity given its carbon backbone, it has already established its potential for use as negative electrode or collector. While the mechanical properties of the manufactured battery were impressive, the electrochemical performance left so much to be desired. Since then, optimizing the balance between loadbearing capability and electrochemical performance has been the goal of the ongoing research. We have strived to remedy this problem and improve upon the tailored manufacturing process through producing a completely novel form of epoxy to encompass the carbon fibers, providing a significant boost to its conductivity as the solid electrolyte. This novel form of epoxy was supplemented by a new tailorable approach of manufacturing cathode through a modifiable spray system.
2. Fully Solid Epoxy Electrolyte
We eliminate this trade-off by establishing a new framework where reactions between liquid electrolyte and polymer species during the curing process can boost both ionic conductivity and retain the mechanical prowess of the epoxy polymer base. We have developed a solid epoxy electrolyte capable of ion transfer in a desiccated state, achieved through a polymer chain and small cluster molecules facilitating the hopping process between polymer chains. This allows changing the ion transfer mechanism from dominant segmental motion above glass transition temperature (Tg) to ion hopping at room temperature much blow Tg. A brief overview of the results is brought in Fig. 1, and compared to the other notable studies in this area. In contrast to the state-of-the-art studies, where incorporating large contents of lithium salt within the epoxy deteriorates the polymer structure, our preliminary results show that the altered chemistry of the epoxy retains a significant portion of its original strength despite the salt content.
3. Patterned Electrode-Electrolyte Interface
Manufacturing a superior electrolyte is only one side of the coin. To use this potential to the greatest extent, creating a seamless cathode-electrolyte remains crucial. We use an in-house supercritical CO2 spray technique to tailor the post-evaporation patterns through changing the ratio of the materials within the droplets. Used as the main supplier of the electrons, lithium iron phosphate (LFP) was mixed with graphene nanoplatelets (GNP) to facilitate the flow of ions within the cell. Our experiments show that shifting the ratio of these materials within the droplets can create a dome or ring post-evaporation patterns that affects the capacity/power balance of cathode, and by extension the battery. The deposited patterns on carbon fibers showed that shifting from ring to dome increases the energy density by 35% in a cell with LiPF6 electrolyte and Li anode. These promising results show the potential of patterning to regulate the electrochemical properties of the manufactured battery.