The electrochemical capacitive behavior of layered double hydroxide containing cobalt and aluminum (Co-Al LDH), synthesized by a "memory effect" route, was in detail evaluated by cyclic voltammetry (CV) and chronopotentiometry in 1 M LiOH aqueous electrolyte. A specific capacitance of 187 F g(-1) was obtained even after 1000 cycles at a current of 2 A g(-1). Moreover, it was found that Co-Al LDH undergoes two independent electrode processes in LiOH aqueous solution, involving the simultaneous intercalation of an ion-pair, i.e. lithium cation and hydroxyl group, which is different from the mechanisms in NaOH and KOH aqueous solutions. The possible reason is thought to be the selective intercalation into Co-Al LDH for alkali metal ions due to their respective ionic radius. Only the cation with appropriate size is suited for inserting into [Co(OH)(6)] or [Al(OH)6] octahedral vacancies. (c) 2008 Elsevier B.V. All rights reserved.