Manipulating the ion-transference and deposition kinetics by regulating the surface chemistry of zinc metal anodes for rechargeable zinc-air batteries

摘要

Aqueous zinc-air battery(ZAB)has attractive features as the potential energy storage system such as high safety,low cost and good environmental compatibility.However,the issue of dendrite growth on zinc metal anodes has seriously hindered the development of ZAB.Herein,the N-doped carbon cloth(NC)prepared via magnetron sputtering is explored as the substrate to induce the uniform nucleation of zinc metal and suppress dendrite growth.Results show that the introduction of heteroatoms accelerates the migration and deposition kinetics of Zn^(2+)by boosting the desolvation process of Zn^(2+),eventually reducing the nucleation overpotential.Besides,theoretical calculation results confirm the zincophilicity of N-containing functional group(such as pyridine N and pyrrole N),which can guide the nucleation and growth of zinc uniformly on the electrode surface by both promoting the redistribution of Zn^(2+)in the vicinity of the surface and enhancing its interaction with zinc atoms.As a result,the half-cell assembled with magnetron sputtered carbon cloth achieves a high zinc stripping/plating coulombic efficiency of 98.8%and long-term stability of over 500 cycles at 0.2 mA cm^(-2).And the Coulombic efficiency reached about 99.5%at the 10th cycle and maintained for more than 210 cycles at a high current density of 5.0 mA cm^(-2).The assembled symmetrical battery can deliver 220 plating/stripping cycles with ultra-low voltage hysteresis of only 11 mV.In addition,the assembled zinc-air full battery with NC-Zn anode delivers a high special capacity of about 429 mAh gZn1 and a long life of over 430 cycles.The effectiveness of surface functionalization in promoting the transfer and deposition kinetics of Zn^(2+)presented in this work shows enlightening significance in the development of metal anodes in aqueous electrolytes.