Micro-Architected Lithium Cobalt Oxide Electrodes toward 3D Solid-State Batteries

Lithium-ion batteries (LIBs) are the primary candidates for advancing energy storage needs, but current LIBs suffer from energy-storage and power limitations of their slurry electrodes, as well as the safety concern from liquid electrolytes. Thickness of commercial slurry electrodes is highly limited by Li ion transport. This constraint on electrode thickness limits the mass ratio between active materials and current collectors, and thus the energy and power density of LIBs. One approach to overcome this limitation is to fabricate 3D architected electrodes using additive manufacturing techniques. In this work, lithium cobalt oxide (LCO) is fabricated into 3D micro-architected structure through a novel hydrogel infusion process. In this process, a blank 3D architected organogel is printed through vat photopolymerization and soaked in water to form a blank hydrogel, where lithium and cobalt ions in an aqueous solution are then swelled into the 3D hydrogel structure. After calcination, LCO micro-lattice with 50 μm beam diameter is obtained, giving a crucial lithium-ion diffusion length of 25 μm. This approach enables LCO cathode to be flexibly architected into 3D geometries, for example the interdigitated plate configuration, toward the realization of 3D Li-ion batteries with high energy and power density. A carbon anode of the same 3D architecture can be fabricated and combined with the LCO cathode, followed by conformal coating and in-situ polymerization of a photo-polymerizable oligo(ethylene glycol)-based gel polymer electrolyte resin on 3D electrodes, giving a 3D solid-state lithium-ion battery.