Lithium-metal nitride cathodes for rechargeable lithium batteries

摘要

Researchers at T/J Technologies have discovered a new cathode material for lithium and lithium-ion batteries: Li{sub}αM{sub}(1-β)T{sub}βN{sub}x where M is the host metal and T is a dopant. The patent status precludes T/J Technologies fromdisclosing the identity of M and T (patents pending: Wixom and Thompson, 1995,1996). This material represents a new class of electronically-conductive cathode materials that are based upon metal nitrides. This material readily undergoes reversible lithium insertion reactions and lithium-diffusion thus enabling its use as a high-capacity, high-rate-capability cathode. We report capacities of 165 mAh/g at C/7 using a liquid electrolyte lithium battery. This performance exceeds that of several layered oxides and spinels. This report presents a brief overview of our recent efforts to assess the performance of the material. We present the results of structural characterization of the electrode material in the charged and discharged states. Test cell data isalso presented: charge-storage capacity, energy density, cyclability, the range ofβ over which performance is optimal, and preliminary estimates of the lithium ion diffusivities.