Electrochemical Characterization of High Energy Density Graphite Electrodes Made by Freeze-Casting

Despite extensive and continuous research to find alternatives, the Li-ion battery community still relies on graphite to manufacture most negative electrodes. Although graphite has many advantages, its relatively low volumetric energy density remains a limiting factor for many heavy-duty applications, such as electric vehicles (EVs) and grid storage. With the aim of increasing cells level energy density and decreasing cost by building thicker electrodes, freeze-casting, a shaping technique able to produce low-tortuosity structures by using ice crystals as a pore-forming agent, is used here to produce porous graphite anodes. The electrochemical performance is assessed using galvanostatic constant current (GCC) charge–discharge as well as hybrid pulse power characterization (HPPC) techniques. The obtained GCC discharge capacities of ∼18, ∼14, and ∼7 mAh/cm2 at C/10, C/5, and 1C, respectively, show a 5-fold enhancement compared with conventional composite electrodes. Finally, our freeze-cast electrodes also meet the pulse power requierements (1C rate pulses) embodied in the HPPC test protocol.