LITHIUM TITANATE PRIMARY PARTICLES, LITHIUM TITANATE AGGREGATE, LITHIUM ION SECONDARY BATTERY USING LITHIUM TITANATE PRIMARY PARTICLES OR LITHIUM TITANATE AGGREGATE, AND LITHIUM ION CAPACITOR USING LITHIUM TITANATE PRIMARY PARTICLES OR LITHIUM TITANATE AGGREGATE

摘要

Provided is a lithium titanate particle active material which is capable of increasing cycle characteristics and electrical capacity during high-rate charging and discharging. Lithium titanate primary particles which are characterized by having a step-like structure wherein smooth polygonal plates are laminated. A lithium titanate aggregate wherein the primary particles having the step-like structure and another lithium titanate primary particles having an arbitrary shape aggregate, said lithium titanate aggregate being characterized in that the number of the primary particles having the step-like structure is not less than 10% of the total number of the primary particles. A lithium ion secondary battery and a lithium ion capacitor, each of which uses the primary particles or the aggregate.