Increasing the thickness of battery electrodes is an attractive approach to reduce the fraction of battery parts that do not store energy, such as current collectors and separators. However, the fabrication of thick electrodes holds challenges of its own such as cracking or flaking during the electrode production and limitations in ion and electron transport. One important contribution from this project is that we developed a scalable roll-to-roll compatible method for fabricating ultrathick electrodes using a phase segregation process. This manufacturing method creates a bi-continuous electrolyte and electrode network with excellent ion and electron transport reducing the charge-transport challenges in thick electrodes. Using this process, electrodes with areal capacities of more than 30mAh/cm2 are demonstrated. Capacity retentions of 87% are attained over 500 charge-discharge cycles. Finally, we verified the scalability of the TIPS process by coating thick electrodes continuously on a pilot-scale roll-to-roll coating tool.
Other advances include the discovery that energy can be stored reliably in anodes using a combination of three different energy storage mechanisms: Intercallation, alloying and plating. By balancing these three mechanisms, stable high energy density anodes were achieved. Finally, an unexpected discovery during this project was the observation that certain material formulations which allow for both storing energy (as in a battery) and harvesting light energy (as in a photo-voltaic cells). Finally, part of our work has been focusing on how to crease better structured active materials, which is being evaluated for patenting and could lead to a new spin out company being created.
