Electrochemical properties of Li₄Ti₅O₁₂-SnO₂ composite powders prepared by scalable spray drying process

Spherical Li₄Ti₅o₁₂-Sno₂ composite powders are prepared using scalable spray drying process from a homogeneous aqueous solution. The composite powders exhibit phase purity, compositional homogeneity, unique morphology, and mixed crystal structures consisting of spinel Li₄Ti₅o₁₂ and rutile Sno₂ without any impurities. Nanosized Sno₂ crystals are uniformly distributed throughout the spinel Li₄Ti₅o₁₂ matrix. The composite powders prepared from the spray solution with 20 wt% excess Li exhibit high initial charge and discharge capacities, 639 and 439 mAh g^-1, respectively, in which the Coulombic efficiency is 69%. The discharge capacity of the composite powders decreases from 439 to 359 mAh g^-1 by the 30th cycle at a current density of 170 mA g^-1, the capacity retention being 82%. The presence of Li₄Ti₅o₁₂ phase decreases the degree of aggregation of the active Sn powders imbedded in the composite powder matrices during cycling. The stable Li₄Ti₅o₁₂ matrix and hollow inner structure of the composite powders also decrease the amount of internal stress due the changes in volume in the composite powder particles during Li intercalation and deintercalation.