Premium
Functionalized Zn@ZnO Hexagonal Pyramid Array for Dendrite‐Free and Ultrastable Zinc Metal Anodes
Author(s) -
Kim Ji Young,
Liu Guicheng,
Shim Ga Young,
Kim Hansung,
Lee Joong Kee
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202004210
Subject(s) - materials science , anode , current density , anodizing , dendrite (mathematics) , zinc , faraday efficiency , electrode , chemical engineering , electrochemistry , metal , coating , nanotechnology , metallurgy , chemistry , aluminium , quantum mechanics , engineering , physics , geometry , mathematics
Abstract Here, an electrode comprising a Zn hexagonal pyramid array (HPA) coated with a functionalized ZnO layer (Zn@ZnO HPA) is prepared using a periodic anodizing technique. The HPA structure markedly increases the electroactive surface area of Zn anode, thus decreasing the local current density. Furthermore, the functionalized ZnO coating layer has a gradient thickness that plays an important role in the selective deposition of Zn ions and the mitigation of side reactions at the interface. The electrochemical stability of the Zn@ZnO HPA electrode, which is closely related to the electroactive surface area and charge transfer resistance, is determined by the “split” value, i.e., ratio of current‐off to current‐on time, a parameter of the periodic anodizing process. Compared with the pristine Zn‐based symmetric cell, the Zn@ZnO HPA‐based symmetric cell is safely operated in the investigated experimental range with the 10‐fold improved running life and 25‐fold enhanced current density without Zn dendrite growth. Moreover, the Zn@ZnO HPA/MnO 2 battery exhibits outstanding long‐term cyclability (nearly 100%) with greater than 99% Coulombic efficiency after 1000 cycles at a current density of 9 A g −1 . This periodic anodizing technique for ultrastable Zn metal anodes is expected to contribute to the development of inherently safe energy storage systems.