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Categories: advanced materials, energy

BSA 11-12: Intermetallic M-Sn₅ (M=Fe, Cu, Co, Ni) Compounds

BNL Reference Number: BSA 11-12

Patent Status: Provisional filed on June 14, 2011

Summary

Among electrode materials for lithium ion batteries, tin offers a high theoretical capacity about 2.5 times that of graphite by weight. Unfortunately, when lithium alloys with tin the matrix undergoes a very large volume change. This change in volume results in a loss of capacity over a few charge-discharge cycles. By adding a transition metal to the tin, this volume change can be mitigated. The novel phase of FeSn₅ or CoSn₅ exhibits a capacity nearly twice that of FeSn₂, the previous champion intermetallic.

Description

Using a modified polyol wet-chemistry method the inventors prepared nanospheres of the new phases, which have tetragonal lattices in the P4/mcc space group. The capacity of FeSn₅ is nearly twice that of FeSn₂. Both FeSn₅ and CoSn₅ have a large number of vacancies on the M site, approximately 25%, leading to quasi-one-dimensional behavior. FeSn₅ is also superparamagnetic, implying that the nanoparticles include at least one component that orders magnetically at or above room temperature.

Have Questions?

For more information about this technology, contact Kimberley Elcess, (631) 344-4151.