ARL's improved cathod material provides over a 1,000,000X improvement in electrical conductivity at optimal lithium doping levels

Improved Lithium Iron Phosphate Cathode

The US Army seeks a licensee to develop and commercialize an improved lithium iron phosphate (LiFePO4) cathode material for use in rechargeable batteries

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Technology Description

Background & Technology:

ARL’s Sensors and Electronic Devices Directorate has developed an improved lithium iron phosphate (LiFePO4) material that offers a lower-cost, more environmentally friendly alternative to commercial lithium cobalt oxide (LiCoO2) for cathodes found in rechargeable batteries. Compared to standard LiFePO4 cathodes, this innovation provides greater conductivity, as well as higher average capacity and charge-discharge rate, yielding a greater range of applications with negligible additional materials or fabrication cost.

LiFePO4 has advantages over transition metal oxide cathode materials such as LiCoO2, common in rechargeable batteries, especially with respect to abuse tolerance. However, low conductivity constrains use as a practical battery component. Fixes such as particle size engineering and applying conductive carbon coatings improve conductivity but lower energy density.

ARL synthesized lithium-doped cathodes, where iron ions in the LiFePO4 material are substituted with lithium ions. This substitution improves conductivity by more than 1,000,000 times as compared to non-doped LiFePO4, making it comparable to LiCoO2, an industry standard. Moreover, the ARL approach increases bulk electronic conductivity, which minimizes loss of energy density. This approach is also attractive in that no foreign atoms are introduced into the material that may be unstable in the electrochemical environment.

The ARL lithium-doped LiFePO4 cathode material also maintains advantages of non-doped LiFePO4, such as
high thermal stability and low reactivity with common electrolytes. Based upon iron, it is also less expensive, more abundant, and environmentally more acceptable than cobalt metal-based cathode material. Fabrication of the new ARL material can be accomplished using existing process lines and materials.

Benefits:

  • Less expensive and more environmentally acceptable than cobalt cathodes
  • Conductive as cobalt and more abuse tolerant
  • Superior conductivity and capacitance as compared to standard LiFePO4

Status and Opportunity:
Issued US Patent No. 7,629,080 is available for license

Supplemental Technical Information:

For more information, contact:
Dan Swanson, CLP (406) 994-7736, dss@montana.edu

Licensing Instructions:

In order to apply for license to federally owned technologies, regulations require that specific information be provided regarding your company and plans for commercialization. This information will be incorporated in a license agreement which will be provided for your review prior to signature. All provided information will be considered proprietary and held confidential.

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