Spinel Li4Ti5O12 hollow nanospheres prepared with colloid carbon spheres as templates for high power Li-ion battery anodes

Abstract

Spinel Li₄Ti₅O₁₂ hollow nanospheres self-assembled with lamellar nanocrystallites have been successfully prepared by employing colloid carbon spheres as templates via a solvothermal reaction route and a subsequent calcination process. During the solvothermal treatment, the amorphous Li₄Ti₅O₁₂ deposits on the colloid carbon spheres, leading to amorphous C@a-Li₄Ti₅O₁₂ core–shell nanospheres. Two calcination strategies, one is to calcine the C@a-Li₄Ti₅O₁₂ core–shell nanospheres in air directly and the other is to first calcine the nanospheres in inert gas of nitrogen and then in air, are investigated for controlling the microstructures of spinel Li₄Ti₅O₁₂ hollow nanospheres. Based on the experimental results, the formation mechanism of the spinel Li₄Ti₅O₁₂ hollow nanospheres has been discussed. The spinel Li₄Ti₅O₁₂ hollow nanospheres obtained by the secondary calcination method exhibit nice capacity retention and high-rate capacity due to the smaller lamellar nanocrystallites and enhanced contact with the electrolytes.