Architected Low‐Tortuosity Electrodes with Tunable Porosity from Nonequilibrium Soft‐Matter Processing

• Published in: Advanced materials (Weinheim) 2023-02, Vol.35 (7), p.e2209694-n/a
• Main Authors: Resing, Anton B., Fukuda, Chase, Werner, Jörg G.
• Format: Article
• Language: English
• Subjects: architected electrodes; Channels; Controllability; Diameters; Electrode polarization; Electrodes; Energy storage; High current; Lithium; low‐tortuosity; Mass transport; Materials science; nonequilibrium processing; Species diffusion; Thickness; Tortuosity
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202209694

Mass transport is performance‐defining across energy storage devices, often causing limitations at high current rates. To optimize and balance the device‐scale energy and power density for a given energy storage demand, tailored electrode architectures with precisely controllable phase dimensions are needed in combination with low‐tortuosity channels that maximize the geometric component of diffusion and species flux. A material‐agnostic nonequilibrium soft‐matter process is reported to fabricate free‐standing inorganic composite electrodes with adjustable thicknesses of 100s of µm, featuring straight and accessible channels ranging in diameter from 5–30 µm, coupled with tunable material‐to‐pore ratios. Such architected anode and cathode electrodes exhibit electrochemical and architectural stability over extended cycling in a full‐cell battery. Further, mass‐transport constraints appear at high current densities, and the lithiation step is identified as rate‐performance limiting, a result of insufficient lithium‐ion supply and concentration polarization. The results demonstrate the need for and feasibility of tailored electrode architectures where dimensional ratios between low‐tortuosity channels, the charge‐storing matrix, and electrode thickness are tunable to meet coupled power and energy‐storage requirements. In energy storage devices, the microstructure of pores and materials is tied to performance. A material‐agnostic process is reported to fabricate free‐standing electrodes with adjustable thicknesses, featuring straight and accessible channels with homogenous diameters in the micrometer range, and tunable pore density. Through this scalable process, feature sizes can be tailored to inform and enable architectures for application‐specific energy storage.