Utilizing Molecular Sieves and Confinement to Improve Li-Air/Oxygen Battery Electrodes

Technology #16881-16882

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Inventors
Professor Ju Li
Department of Nuclear Science and Engineering, MIT
External Link (li.mit.edu)
Akihiro Kushima
Department of Nuclear Science and Engineering, MIT
External Link (web.mit.edu)
Tetsuya Koido
Honda R&D Company, Ltd.
Yoshiya Fujiwara
Honda R&D Company, Ltd.
Managed By
Christopher Noble
MIT Technology Licensing Officer - Clean and Renewable Energy
Patent Protection

Air secondary battery

US Patent Pending 2016-0064788

Air secondary battery

US Patent Pending 2016-0064787

Applications

Lithium-air/oxygen batteries (LABs) have much higher capacities than existing batteries, and with improved rate capability can be used in applications such as portable electronics or electric vehicles.

Problem Addressed

A slow charge/discharge rate is one of the issues that prevent LABs from practical applications. This technology proposes four design improvements to increase the charge/discharge rate.

Technology

The first improvement is the implementation of a molecular sieve in the cathode. This sieve is created with zeolite and has an advantage over commonly used porous electrodes because it provides separate paths for oxygen/air and the electrolyte. This eliminates the growth of lithium oxide which can block the pores and prevent oxygen from reaching the reaction site resulting in poor capacity. The other improvements address detached discharge products that cause poor cycle performance in LABs. The first is a porous electrode with dimples to increase the binding strength between the LAB discharge products and the electrode to prevent detaching during charge. These dimples can be easily implemented by adding ceramic nanoparticles to production that are later removed using nitric acid. The last improvements are a change in the electrode design. The first is an inner layer with larger pores and an outer layer with smaller pores to trap particles in the inner electrode so they will not detach. The second is to provide separate electrical circuits to the inner and the outer electrodes and physically separate them with an insulation layer or simply space between them.  These separate circuits allow only the inner electrode to be supplied during discharge and both parts to be supplied during charge. This allows lithium oxide grown on the inner layer to be trapped in the outer layer during charging for further decomposition. Confining the reaction products and creating different pathways for the electrolyte and oxygen/air improves the charge/discharge rate and the cycle performance of a Lithium-air/oxygen battery.

Advantages

  • Improves charge/discharge rate
  • Improves cycle performance