A modified separator based on ternary mixed-oxide for stable lithium metal batteries.

Li metal batteries (LMBs) are among the most promising options for next-generation secondary batteries under the rapidly growing demand for high-energy-density electrochemical energy storage. However, the implementation of LMBs are hindered by major obstacles such as dentritic Li deposition and low cycling Coulombic efficiency. A practical functional separator is developed in this study, which consists of a Lewis acidic mixed oxide of ZrO ₂ -SiO ₂ -Al ₂ O ₃ as a functional coating with anion anchoring ability to modulate ion transport in the vicinity of the Li metal anode, delivering a high Li ⁺ transference number of 0.88 in carbonate electrolytes that suppresses dendrite formation. The strong Lewis acid sites in ZrO ₂ -SiO ₂ -Al ₂ O ₃ originate from coordinatively unsaturated Zr ⁴⁺ ions, which immobilize anions and reduce their decomposition rate. This significantly improves the chemical stability of the electrolyte and induces a more stable solid electrolyte interphase layer. The modified separator enables an anode-free cell containing a high-loading LiNi _0.8 Co _0.1 Mn _0.1 O ₂ cathode to present stable charge and discharge cycling for 150 cycles at 0.5C. By effectively suppressing Li dendrite growth and supporting the long-term operation of anode-free LMBs, this study offers a novel approach to rationally design mixed oxides with high Lewis acidity for functional separators.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Inc. All rights reserved.)