Will advanced lithium-alloy anodes have a chance in lithium-ion batteries?

The high packing density of lithium is a significant advantage of lithium insertion into metallic matrices that can be achieved in lithium alloys compared with lithium intercalation into carbonaceous materials. Moreover, the operating voltage of lithium-alloy anodes may be chosen well-above the potential of metallic lithium and the solvent co-intercalation has not been observed at lithium-alloy electrodes, On the other hand, the volume changes related with insertion/removal of lithium into/from the metallic matrices cause pulverization and rapid failure of lithium-alloy anodes. This paper demonstrates the dramatic effect of the morphology of the metallic host matrix on the performance of the lithium-alloy anodes. Two component host matrices with ultrasmall (submicro- or nanoscale) particle size show an impressive cycling performance. This is related with the small absolute changes of the dimensions of the individual particles and also with the fact that in the first charging step the more reactive particles are allowed to expand in a ductile surrounding of still unreacted material. (C) 1997 Elsevier Science S.A.