PNNL

Abstract

The high energy density advantage of lithium (Li) metal batteries (LMBs) makes them increasingly desirable; however, problems such as strong reactivity and dendrite growth of Li metal anode limit their practical use. In this work, we employ a novel Li-containing glycerol (LiGL) or lithicone protection layer on a 50 µm thick Li metal anode for improving the performance of LMBs. This LiGL layer was accurately deposited via a molecular layer deposition (MLD) process at 150 ºC, using lithium tert-butoxide and glycerol as precursors. The as-formed LiGL coating layer is highly tunable in its thickness by simply adjusting MLD cycles and shows a good stability and outstanding ionic transport properties. The LiGL layer is found to effectively mitigate side reactions and enhance cycling stability in both symmetric cells and full cells. Specifically, the LMBs with LiGL@Li anode of 400 MLD cycles and LiNi0.6Mn0.2Co0.2O2 cathode enable a capacity retention of ~87%, much higher than ~35% of the cells with bare Li after 200 cycles at a charge/discharge current density of 2.1 mA cm–2. This work paves a feasible way for practical LMBs with improved capacity and stability through applying an innovative protection layer on Li metal anodes.