摘要
The practical applications of aqueous Zn metal batteries are currently restricted by the inherent drawbacks of Zn such as the hydrogen evolution reaction,sluggish kinetics,and dendrite formation.To address these problems,herein,a limitedly Zn-doped MgF_(2)interphase comprising an upper region of pure,porous MgF_(2)and a lower region of gradient Zn-doped MgF_(2)is achieved via radio frequency sputtering technique.The porous MgF_(2)region is a polar insulator whose high corrosion resistance facilitates the de-solvation of the solvated Zn ions and suppression of hydrogen evolution,resulting in Zn metal electrodes with a low interfacial resistance.The Zn-doped MgF_(2)region facilitates fast transfer kinetics and homogeneous deposition of Zn ions owing to the interfacial polarization between the Zn dopant and MgF_(2)matrix,and the high concentration of the Zn dopant on the surface of the metal substrate as fine nuclei.Consequently,a symmetric cell incorporating the proposed Zn metal exhibits low overpotentials of~27.2 and~99.7 mV without Zn dendrites over 250 to 8000 cycles at current densities of 1.0 and 10.0 mA cm−2,respectively.The developed Zn/MnO2 full cell exhibits superior capacity retentions of 97.5%and 84.0%with average Coulombic efficiencies of 99.96%after 1000 and 3000 cycles,respectively.
基金
supported by research grants from the National Research Foundation(NRF-2019H1D3A1A01069779)funded by the Ministry of Science and ICT,Republic of Korea,and by the Institutional Program(2E31863)and Bridge Program-KIST(2V09284).
