Engineering the Li-ion flux and interfacial chemistry toward a stable Li metal anode a simple separator coating strategy

• Published in: New journal of chemistry Vol. 47; no. 17; pp. 7986 - 7994
• Main Authors: Zhao, Sheng, Ma, Mingze, Gao, Liangyu, Gu, LanHui, Chen, Minfeng, Han, Guangdong, Yang, Tingrui, Chen, Jizhang, Qi, Dongfeng, Wang, Peng, Han, Xiang
• Format: Journal Article
• Published: 02.05.2023
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj01086d

Due to its remarkably high specific capacity of 3860 mA h g −1 and low reduction potential (−3.04 V vs. SHE), lithium metal has been identified as an ideal anode candidate for high-energy density lithium-ion cells. However, the growth of lithium dendrites caused by the deposition of lithium metal can affect the charge and discharge behavior of a cell and lead to short circuit, which is a safety concern and hinders its practical applications. Here, we prepare a composite separator polypropylene-Li 1+ x Al x Ti 2− x (PO 4 ) 3 -indium tin oxide (PP-LATP-ITO) via a simple slurry coating method. The coating of LATP-ITO demonstrates unique advantages of Li-ion deposition as well as interfacial chemistry. Firstly, lithiophilic PP-ITO helps to reduce the energy barrier for Li deposition. In addition, the three-dimensional ion channels can regulate the transport of lithium ions and induce uniform Li metal plating and stripping. Furthermore, the in situ formed interface comprising of a Li-In alloy, Li 3 PO 4 and LiF enables stable interfacial chemistry. As a result, compared with the PP separators, the voltage stability of the composite separators in Li-Li symmetric cells is greatly improved during the charge and discharge cycling. In addition, LCO/Li cells with the composite separator PP-LATP-ITO exhibit a higher specific capacity (140 mA h g −1 ) and good capacity maintenance during cycling. This work proposes a separator coating strategy that can inhibit dendrite formation and stabilize the lithium metal interface. In this study, a composite separator was prepared by simple LATP and ITO coating on PP, which not only induces uniform Li metal plating and stripping but also helps to form stable interphases that comprise of Li 3 PO 4 and LiF.