Realizing Highly Reversible Zinc Anode via Controlled-current Pre-deposition

Aqueous zinc ion batteries have been considered as the prominent candidate in the next-generation batteries for its low cost,safety and high theoretical capacity.Nonetheless,formation of zinc dendrites and side reactions at the electrode/electrolyte interface during the zinc plating/stripping process affect the cycling reversibility of the zinc anode.Regulation of the zinc plating/stripping process and realizing a highly reversible zinc anode is a great challenge.Herein,we applied a simple and effective approach of controlled-current zinc pre-deposition at copper mesh.At the current density of 40 mA cm^(-2),where the electron/ion transfers are both continuous and balanced,the Zn@CM-40 electrode with the(002)crystal plane orientation and the compactly aligned platelet morphology was successfully obtained.Compared with the zinc foil,the Zn@CM-40 exhibits greatly enhanced reversibility in the repeated plating/stripping(850 h at 1 mA cm^(-2))for the symmetric battery test.A series of characterization techniques including electrochemical analyses,XRD,SEM and optical microscopy observation,were used to demonstrate the correlation between the structure of pre-deposited zinc layer and the cycling stability.The COSMOL Multiphysics modeling demonstrates a more uniform electric field distribution in the Zn@CM than the zinc foil due to the aligned platelet morphology.Furthermore,the significant improvement is also achieved in a Zn||MnO_(2)full battery with a high capacity-retention(87%vs 47.8%).This study demonstrates that controlled-current electrodeposition represents an important strategy to regulate the crystal plane orientation and the morphology of the pre-deposited zinc layer,hence leading to the highly reversible and dendrite-free zinc anode for high-performance zinc ion batteries.