3M’s lithium battery cathode technology utilizes proprietary layered mixed metal oxide formulations of nickel, manganese and cobalt (NMC), providing a balance of power, energy, and safety characteristics that can be optimized through changes in composition and morphology to meet application requirements from high-energy, handheld consumer electronics to high-power (hybrid) electric vehicles. The lower cobalt content optimizes performance, while providing low and stable pricing.

For large format battery applications, the excellent thermal stability of NMC cathode compositions contributes to improved battery safety performance and enables a lower total battery system cost.

The basic design of the layered NMC material is:

xLiCoO₂ · (1-x)LiMn_½Ni_½O₂    0<x<1

If cobalt decreases, thermal stability increases; crystal density decreases; lithium diffusion coefficient/rate capability decreases; and raw material cost significantly decreases. Rate capability increase with Co.

3M’s battery laboratory has collaboration with Professor Jeff Dahn and students at Dalhousie University on the NMC technology. 3M has developed a number of compositions of the NMC material, including NMC 111 (for energy and power); NMC 442 (for energy and power); and an optimized high-power NMC 111 composition with high porosity.

Recently, the United States Patent and Trademark Office (USPTO) issued an Ex Parte Reexamination Certificate for US Patent 7,078,128. As a result of the reexamination, the USPTO confirmed the patentability of all of 3M’s originally issued claims and no amendments were made to the patent.

Resources

• US Patent Nº 6,660,432: Lithiated oxide materials and methods of manufacture (Paulsen)

• US Patent Nº 6,964,828: Cathode compositions for lithium-ion batteries (Lu-Dahn)

• US Patent Nº 7,028,128: Cathode compositions for lithium-ion batteries (Lu-Dahn)

• US Patent Nº 8,241,791: Cathode compositions for lithium-ion batteries (Lu-Dahn)