Here we report a non-sintering, emulsion-based, magnetic-alignment method that is simple, scalable, and naturally produces aligned porosity favorably oriented normal to the electrode plane. Unlike previous magnetic-alignment methods, which may only work with anisotropic particles such as natural graphite flakes (as anode),4, 5 our method is not limited to certain particle shapes or electrode materials and can be generally applied to both cathodes and anodes without sintering. We prepare thick LiCoO2 cathodes (>400 µm) with ultrahigh areal capacity (up to ~14 mAh cm−2 versus 2-4 mAh cm-2 of conventional electrodes) through magnetic alignment of emulsion-based slurries. The LiCoO2 cathodes are confirmed to have low tortuosity via DC-depolarization experiments and deliver high areal capacity (>10 mAh cm-2) in galvanostatic discharge tests at practical C-rates and model electric vehicle drive-cycle tests. This simple fabrication method can also be applied to meso-carbon microbead (MCMB) graphite anodes and potentially many other materials to enable high energy-density full batteries based on thick electrodes.
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This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231, Subcontract No. 7056592 under the Advanced Battery Materials Research (ABMR) Program.