alpha-Ni(OH)(2) nanosheets were prepared at room temperature on ultra large scale through a solvent-free reaction. The nanosheets were obtained by grinding the mixture of nickel nitrate hexahydrate and morpholine in a mortar for 5 min. The maximum capacity of production in single batch was only limited by volume of the vessels used in preparation. The as-prepared nanosheets exhibited the highest specific capacitance of 2080.8 F g (1) at discharge current density of 0.6 A g (1) in a 6 mol l (1) KOH aqueous solution. The nanosheets also presented other high electrochemical performances such as nearly 100% coulombic efficiency, excellent rate capacity and high stability. These results indicated that the alpha-Ni(OH)(2) nanosheets can be used as a high performance electrochemical material for application in supercapacitor. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.