Zinc-Carbon Paper Composites as Anodes for Zn-Ion Batteries: Key Impacts on Their Electrochemical Behaviors

Zn metal, with abundant resource and low cost, exhibits large theoretical capacity and relatively negative electrode potential (-0.76 V vs SHE), which endows zinc-ion batteries with promising energy storage systems. Though great efforts have been made recently, challenges remain in the development of Zn-ion batteries, especially for the zinc anode. The zinc dendrite formation and reaction irreversibility during cycling lead to increased polarization and poor cycle performance of the battery. In addition, a Zn plate is usually used as anode when the battery is assembled, which is far beyond the theoretical quantity of Zn requested in the redox reaction, which resulted in low energy density of the battery. Zn and carbon composites are reported in literature as an efficient strategy to address these problems, yet the impact of the preparation of Zn/C composites, the corresponding structure, and the charge/discharge parameters on their electrochemical performance are not revealed. In this contribution, Zn@Carbon paper (CP) was prepared via electrodeposition of Zn on carbon paper and used as anode of the zinc-ion battery. It is found that the morphology and electrochemical performance of Zn@CP are quite dependent on the electrodeposition current density during preparation, which might be related to nucleation activation energy at the beginning of the electrodeposition. Beyond the preparation of Zn@CP, the depth of discharge (DOD) during cycling is crucial in determining its electrochemical behavior. This work would benefit the design of Zn-based composite anode materials for further advancement of Zn-ion batteries with superior performance.