Lithium Anode Protective Layers for Li-Air Batteries

Technology #16045

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a s4( a) is a schematic illustration of layer-by-layer (LbL) assembly on polypropylene (PP) membrane; FIG. 4( b) is a scanning electron microscope (SEM) top-down image of pristine porous PP membrane; FIG. 4( c) is an SEM top-down image of polymer top layer after LbL-assembly on pristine membrane; FIG. 4( d) is an AFM image of graphene oxide top layer during LbL-assembly; and FIG. 4( e) is an SEM cross sectional image of 12 tetralayers of LbL-assembly on a porous membrane.chematic drawing depicting a multilayer structurea schematic drawing depicting a multilayer structure6( a) shows the thickness change of LbL layers versus the number of tetralayers; FIG. 6( b) shows ionic conductivities of pristine membrane and LbL-assembled membrane with GO; FIG. 6( c) shows electrolyte permeabilities of whole LbL-assembled membranes (PP membrane+LbL layers) with and without GO incorporation; and FIG. 6( d) shows the calculated intrinsic permeabilities of LbL layers without support membrane. Red dots/bars are for (PEO/GO/PEO/P AA), and black dots/bars are for (PEO/P AA)2n. n means the number of tetralayers.  7( a) and 7(b) show comparisons of thickness and ionic conductivities of LbL modified membranes under three circumstances: LbL with GO and without LiBOB in polymer solution (black), LbL with GO and LiBOB in polymer solution (red), and LbL without GO and with LiBOB in polymer solution (blue).a table that shows a comparison of short-circuit time of test cells, thickness and roughness for pristine and LbL-assembled membranes with and without GO.
Categories
Inventors
Professor Paula Hammond
Department of Chemical Engineering, MIT
External Link (hammondlab.mit.edu)
Sun Hwa Lee
Department of Chemical Engineering, MIT
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

Multi-Layer Structures Prepared By Layer-By-Layer Assembly

US Patent Pending 2014-0186724
Publications
Li-Anode Protective Layers for Li Rechargeable Batteries via Layer-by-Layer Approaches
Chemistry of Materials, March 24, 2014, p. 2579

Applications

This technology is relevant to high energy density batteries, such as for electrical vehicles.

Problem Addressed

Lithium-air batteries can have energy densities that rival gasoline.  However, the lithium-air chemistry can be difficult to manage, making the cycle life much shorter than conventional lithium-ion batteries.  This technology increases lithium-air cycle life by protecting the lithium anode from dendrite growth.

Technology

Current lithium-air battery designs place a polymer separator directly in contact with the lithium anode to separate the anode and cathode sides of the battery.  The separator prevents the battery from short circuiting and absorbs liquid electrolyte to complete the electrical circuit.  The lithium anode, however, can form dendrites during battery cycling that can penetrate the separator and short the battery.  This technology modifies commercially available polymer separator membranes with ion-conductive polymer and graphene oxide layers.  The ion-conductive polymer layers reduce direct contact between the electrolyte and the lithium anode without significantly reducing ion conductivity.  This slows electrolyte corrosion on the anode.  The graphene oxide layers protects the anode from contaminates and prevent chemical fluctuations on the surface of the lithium anode.  Together, these two types of layers stabilizes the lithium anode, which slows down the growth of lithium dendrites and improves the battery's cycle-life.

Advantages

  • Increases cycle life of lithium-air batteries
  • Simple and universal synthesis method
  • Compatible with current commercial polymer membranes separators