We developed scalable process to construct bi-continuous Li-ion battery electrodes using thermally induced phase separation (TIPS) as described in the proposal. TIPS is a robust process as it only relies on changes of material solubility with temperature. It is therefore easy to scale-up, and suitable for manufacturing thick battery electrodes. The TIPS process creates a bi-continuous network of electrolyte providing good ion transport and electrode allowing for excellent electron transport. Importantly, we found an electrolyte that can be used as a solvent to drive the TIPS process. Specifically, all the electrode components such as active material, carbon additive and binder are simply mixed with the electrolyte while heating, and as they cool down, the TIPS process drives the bi-continuous network formation without the need for any additional solvent. This process is attractive because it incorporates the electrolyte as a continuous network, while compacting the electrode phase such as active material, carbon additive and binder without the need for drying, which represents important energy savings especially for thick electrodes and alleviates the need of solvent trapping. This new drying-free electrode fabrication approach also addresses the cracking and flaking problems which occur during the drying of classic thick battery electrodes. 500 µm thick electrodes made by this process outperform standard 60 to 150 µm thick electrodes both in areal and gravimetric capacity, even at high rates of 10C. Areal capacities of up to 24.3 mAh/cm2 are achieved using standard intercalation materials (LTO, LFP and NMC), resulting in excellent cycling stability. Capacity retentions of 87% are achieved over 500 cycles in full cells with 1 mm thick anodes and cathodes.
