Tailoring Electrode Architectures via Self-Assembly for Scalable Energy Storage Systems

Replacing fossil fuels-powered vehicles with electric ones is an indispensable part of achieving carbon neutrality in the near future. Although the past decade has witnessed the unprecedented growth of electric vehicle market, long endurance and fast-charging capacities are the two main challenges remained. This asks for lithium-ion batteries, the heart part of the electric vehicle, with both high energy/power and scalability. In this talk, I will present our recent research progress on understanding the underlying charge transport kinetics and designing tailorable electrode architectures via self-assembly enabling high-rate capabilities in scalable thick electrodes. First, electrode-scale alignment is achieved via assembling porous magnetite (Fe₃O₄) nanosheet building blocks under a controllable magnetic field. Electrode architecture-correlated electrochemical properties are quantitatively explored, revealing the merit of low tortuosity characteristics for rapid charge transport from the nano- to microscale. In addition, a high-density yet low-tortuosity electrode is fabricated by magnetic-assisted self-assembly and drying-induced densification of Fe₃O₄ nanoparticle-decorated graphene oxide building blocks. Vertically assembled channels ensure good electrolyte penetration and material utilization, enabling well-maintained charge storage capability when scaling up the electrode thickness. Besides, a universal bidirectional freeze casting methodology is also explored to artificially induce material assembly to form the densely-packed lamellar structure. Simultaneous high areal capacity and rate capability could be realized in various materials-based electrodes attributed to the efficient mass transport in the ordered assembled architecture. Coupled with advanced three-dimensional visualization techniques, our research provides an in-depth understanding of the spatial mass distribution effects on electrochemical properties in thick electrodes, which could offer multiscale design considerations for next-generation scalable energy storage systems.