Spray layer-by-layer membranes can prevent dendritic growth in lithium battery anode layers.
Li metal is highly reactive and a stable solid electrolyte interphase (SEI) often forms on the Li surface, which allows Li deposition to occur in dendritic morphologies that can short-circuit the battery. This technology prevents dendritic growth through a membrane fabricated through a layer-by-layer (LBL) deposition process that allows the incorporation of a polymer support to provide controlled permeability and selective ion transport.
To reduce processing time, spray LBL is used rather than dipping LBL. Spray LBL deposition reduces the processing time for 6 tetralayers from 8 hours to 10 minutes compared to dipping LBL. LBL film is constructed using a custom-made programmable spray LBL device. Polypropylene (PP) membranes are attached on a glass substrate by a narrow double sided tape and treated with O2-plasma for 30 seconds. The support membranes are first immersed in a Polyethylene Oxide (PEO) aqueous solution for 15 minutes and immersed in a rinsing solution for 2 minutes, followed by a 1 minute rinse immersion. Then the substrate is exposed to a graphene oxide (GO) aqueous solution (0.17 mg/ml) for 15 minutes and rinsed as before. The PP membrane is then dipped in the same PEO solution and rinsed as before. Finally, the PP membrane is immersed in Polyacrylic Acid (PAA) aqueous solution for 15 min, followed by the same rinse process with deionized water. This forms one tetralayer. Up to 24 tetralayers can be used for one anode membrane.
Suppresses Li dendritic growth