Graphite Foams for Lithium-Ion Battery Current Collectors

Graphite open-cell foams, with their very high electronic and thermal conductivities, may serve as high surface area and corrosion resistant current collectors for lithium-ion batteries. As a proof of principle, cathodes were prepared by sintering carbon-coated LiFePO4 particles into the porous graphite foams. Cycling these cathodes in a liquid electrolyte cell showed promising performance even for materials and coatings that have not been optimized. The specific capacity is not limited by the foam structure, but by the cycling performance of the coated LiFePO4 particles. Upon extended cycling for more than 100 deep cycles, no loss of capacity is observed for rates of C/2 or less. The uncoated graphite foams will slowly intercalate lithium reversibly at potentials less than 0.2 volts versus lithium.