2008

Oxide Fiber Cathode Materials for Rechargeable Lithium Cells

LiCoO2 and LiNiO2 fibers have been investigated as alternatives to LiCoO2 and LiNiO2 powders used as lithium-intercalation compounds in cathodes of rechargeable lithium-ion electrochemical cells. In making such a cathode, LiCoO2 or LiNiO2 powder is mixed with a binder [e.g., poly(vinylidene fluoride)] and an electrically conductive additive (usually carbon) and the mixture is pressed to form a disk. The binder and conductive additive contribute weight and volume, reducing the specific energy and energy density, respectively.

In contrast, LiCoO2 or LiNiO2 fibers can be pressed and sintered to form a cathode, without need for a binder or a conductive additive. The inter-grain contacts of the fibers are stronger and have fewer defects than do those of powder particles. These characteristics translate to increased flexibility and greater resilience on cycling and, consequently, to reduced loss of capacity from cycle to cycle. Moreover, in comparison with a powder-based cathode, a fiber-based cathode is expected to exhibit significantly greater ionic and electronic conduction along the axes of the fibers. Results of preliminary charge/discharge-cycling tests suggest that energy densities of LiCoO2-and LiNiO2-fiber cathodes are approximately double those of the corresponding powder-based cathodes.

This work was done by Catherine E. Rice and Mark F. Welker of TPL, Inc., for Johnson Space Center.

In accordance with Public Law 96-517, the contractor has elected to retain title to this invention. Inquiries concerning rights for its commercial use should be addressed to:

TPL, Inc.
3921 Academy Parkway North, NE
Albuquerque, NM 87109-4416

Refer to MSC-22892-1, volume and number of this NASA Tech Briefs issue, and the page number.

White Papers

4 Steps In Selecting Fluid Connectors For Medical Device And Equipment Applications
Sponsored by CPC
When Wire Feedthroughs Make Sense
Sponsored by Douglas Electrical Components
Tech Trend Report: Will GaN Knock out Silicon Semiconductors?
Sponsored by Intercomp
Reducing Development Cycles for 3U VPX Systems
Sponsored by Curtiss-Wright Controls Embedded Computing
Full RF Signal Chains from 0 Hz to 110 GHz
Sponsored by Avnet
How to Turn Your Engineers Into Product Design Superheroes
Sponsored by Arena Solutions

White Papers Sponsored By:

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.