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 similar to 18, similar to 14, and similar to 7 mAh/cm(2) 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.