Preparation of Three Dimensionally Ordered Macroporous Li4Ti5O12 Electrode

Three dimensionally ordered macroporous (3DOM) Li4Ti5O12 was successfully prepared by a colloidal crystal templating process. Colloidal crystal consisting of monodisperse polystyrene particles (1 9m diameter) was used as a template for the synthesis of macroporous Li4Ti5O12. A precursor sol consisting of titanium isopropoxide and lithium acetate was injected into the template, and it was calcined at high temperatures. A macroporous membrane of Li4Ti5O12 with inverse-opal structure was obtained. The prepared material had a spinel-related crystallographic structure. The interconnected pores with uniform size (0.8 9m) were clearly observed on entire part of the membrane. The electrochemical properties of the 3DOM Li4Ti5O12were characterized with cyclic voltammetry and glavanostatic charge-discharge in an organic electrolyte containing a lithium salt. 3DOM Li4Ti5O12 exhibited a discharge capacity of 160 mA h g-1 at the electrode potential of 1.55 V vs. Li/Li+ due to the solid state redox of Ti3+/4+ accompanying with Li+ ion insertion and extraction. The discharge capacity was close to the theoretical capacity (167 mA h g-1). This means that the Li+ insertion and extraction took place at all part of the 3DOM Li4Ti5O12 membrane.