Is High Current Density Necessarily Unfavorable for the Cycling of Zn-Ion Batteries? An in Situ XRD Investigation

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High rate (i.e., high current density) cycling has always been discouraged in the practice of Li-ion and Na-ion batteries because the charging/discharging high current can expedite the electromechanical degradation of the cathodes and result in dendrites formation on the anodes. But is this a universal rule of thumb for all rechargeable batteries? Our recent research on Zinc-ion batteries (ZIBs) shows that this might not be the case. ZIBs employing aqueous electrolytes show great promise for large-scale energy storage due to their affordability, environment-friendliness, and safety. ZIBs also suffer from the formation of harmful zinc dendrites. Conventionally, it was believed that high current density exacerbates dendrite growth, as seen in the electrodeposition of metals like Li. Yet, our recent research indicates that high-current deposition in metallic zinc anodes yields a dense, even layer with a specific (002) texture, thus enhancing cycling lifespan. Conversely, low-current deposition leads to porous, dendritic structures and reduced cycling longevity. Leveraging advanced synchrotron-based in situ X-ray diffraction, we have systematically investigated zinc deposition under varied conditions, unveiling a novel mechanism behind texture formation. These insights inform the development of new cycling protocols to extend the durability of ZIBs significantly.