Case 12347

Nano-sized coatings to improve cyclability, rate capability and capacity retention of olivine electrode materials for rechargeable lithium ion batteries

Keywords:

Energy storage material, amorphous coating, lithium ion battery, lithium iron phosphate, charge discharge rate, cyclability, in-situ surface coating, olivine material, ex-situ coating material, non-stoichiometry, surface coating material

Applications:

Energy storage devices such as lithium ion batteries

Problem:

    Improving charge retention and charge/ discharge rates of LiMPO4 materials through coatings

Technology:

This invention describes a method to make nano-sized active materials of iron-based phosphates with an ion and electron conducting coating. The coating, consisting of an amorphous or microcrystalline glass of Li-P-O-N-Fe, is a stable ionic and electronic conductor. It adheres well to lithium metal phosphate particles, and can be applied in-situ (during synthesis of the material) or ex-situ (after synthesis). The in-situ or ex-situ method is applied to improve electrochemical performance of olivine electrode materials. This novel coating improves the performance, much more than with carbon, of rechargeable lithium ion batteries. The materials synthesized by the surface coating show superior performance in terms of cyclability, rate capability and capacity retention.

Advantages:
  • Coated material leads to best performance that has so far been observed for LiFePO4, enabling charge rates of 60C
  • Extremely stable and adheres well to lithium metal phosphate particles
  • Very good ionic and electronic conductor
  • Can be applied in situ or ex situ of the electrode material

Inventors:
  • Professor Gerbrand Ceder (Department of Materials Science and Engineering, MIT)
  • Byoungwoo Kang (Department of Materials Science and Engineering, MIT)

Intellectual Property:

U.S. Patent Application Number 12/449116, filed on December 28, 2009

PCT Patent Application Number US08/001052, filed on January 25, 2008

Publications:

Gerbrand Ceder and Byoungwoo Kang. Battery Materials for ultrafast charging and discharging. Nature 458, 190-193 (2009), DOI:10.1038/nature07853

Last revised: January 18, 2012

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