An improved 9 micron thick separator for a 350 Wh/kg lithium metal rechargeable pouch cell.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 36357423.
- Also identified by DOI 10.1038/s41467-022-34584-z and PMC identifier 9649724.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The use of separators that are thinner than conventional separators (> 20 µm) would improve the energy densities and specific energies of lithium batteries. However, thinner separators increase the risk of internal short circuits from lithium dendrites formed in both lithium-ion and lithium metal batteries. Herein, we grow metal-organic frameworks (MOFs) inside the channels of a polypropylene separator (8 µm thick) using current-driven electrosynthesis, which aggregates the electrolyte in the MOF channels. Compared to unmodified polypropylene separators, the MOF-modified separator (9 µm thick) vastly improves the cycling stability and dendrite resistance of cells assembled with Li metal anodes and carbonate-based electrolytes. As a demonstration, a 354 Wh kg<sup>-1</sup> pouch cell with a lithium metal anode and LiNi<sub>0.8</sub>Co<sub>0.15</sub>Al<sub>0.05</sub>O<sub>2</sub> (NCA)-based cathode (N/P = 3.96) is assembled with 9 µm layer of the MOF-modified separator and retains 80% of its capacity after 200 cycles (charged at 75 mA g<sup>-1</sup>, discharged at 100 mA g<sup>-1</sup>) at 25 °C.