Regulating Dendrite-Free Zn Deposition by a Self-Assembled OH-Terminated SiO2 Nanosphere Layer toward a Zn Metal Anode

Yi Yang; Tao Chen; Mingke Zhu; Gang Gao; Yinming Wang; Qianqian Nie; Yunpeng Jiang; Ting Xiong; Wee Siang Vincent Lee; Junmin Xue

doi:10.1021/acsami.2c09144

Regulating Dendrite-Free Zn Deposition by a Self-Assembled OH-Terminated SiO₂ Nanosphere Layer toward a Zn Metal Anode

ACS Appl Mater Interfaces. 2022 Aug 24;14(33):37759-37770. doi: 10.1021/acsami.2c09144. Epub 2022 Aug 15.

Authors

Yi Yang¹, Tao Chen^{1

2}, Mingke Zhu¹, Gang Gao¹, Yinming Wang¹, Qianqian Nie³, Yunpeng Jiang¹, Ting Xiong¹, Wee Siang Vincent Lee¹, Junmin Xue¹

Affiliations

¹ Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore.
² School of Chemistry and Chemical Engineering, Nanjing University of Science and Technology, 200 Xiaolingwei Street, Nanjing 210094, China.
³ Department of Mechanical Engineering, National University of Singapore, Singapore 117576, Singapore.

PMID: 35968759
DOI: 10.1021/acsami.2c09144

Abstract

Zn dendrite growth during repeated plating and stripping of a Zn metal anode often causes short-circuiting by puncturing the separator. Herein, we propose a separator modification strategy to regulate the Zn-ion flux and achieve uniform Zn deposition through the OH-terminated SiO₂ nanosphere coating. The interspaces between the uniform SiO₂ nanospheres construct a network of Zn-ion transport channels, and the negatively charged hydroxyl groups on the surface of SiO₂ nanospheres can electrostatically attract the Zn ions to direct the ion migration. The negative charges on SiO₂ nanospheres are retained at a higher pH, which enables the SiO₂ coating to consistently regulate the Zn-ion flux in the operating pH range of the Zn stripping/plating process. With a uniform Zn deposition guided by the SiO₂ coating, the dendrite formation is suppressed and the side reactions are alleviated. As a result, the Zn||Zn symmetric cell achieves a cyclic life of 1000 h at both 3 and 5 mA cm^-2. Meanwhile, the Zn||Cu asymmetric cell is able to maintain a Coulombic efficiency of 99.62% at 1 mA cm^-2 for 2000 cycles, which outperforms many previously reported strategies.

Keywords: SiO2; negative charges; separators; zinc dendrite; zinc metal anodes.