Lithium titanate primary particles, lithium titanate aggregates, lithium ion secondary battery and lithium ion capacitor using them

摘要

Provided is a lithium titanate particle active material capable of further improving electric capacity and cycle characteristics during rapid charge / discharge. Lithium titanate primary particles characterized by having a stepped structure in which smooth polygonal planes are laminated. Further, a lithium titanate aggregate formed by aggregating primary particles having this step-like structure and lithium titanate primary particles having other arbitrary shapes, wherein the step-like structure is formed with respect to the total number of primary particles. Lithium titanate aggregates, wherein the number of primary particles is 10% or more. Furthermore, a lithium ion secondary battery and a lithium ion capacitor using these primary particles and aggregates.