In this study, alpha-Ni(OH)(2) with controllable pristine crystal size is directly electrodeposited on a substrate of Ti wire mesh to fabricate the integrated electrode. The nanoscale effects on morphology, microstructure and electrochemical performance of the cathodic deposited alpha-Ni(OH)(2) are studied. The results show that the morphology of alpha-Ni(OH)(2) varies from irregular honeycomb-like nanopieces, ball-shaped particles to oval nanoplates as the cathodic deposition current density increases. The nanostructure diversity of the cathodic deposited alpha-Ni(OH)(2) is due to the different nanosize which directly depends on the cathodic deposition current density. The electrochemical performances of the cathodic deposited alpha-Ni(OH)(2) increase with the decrease of the pristine crystal size of alpha-Ni(OH)(2). The oval alpha-Ni(OH)(2) nanoplates consisting of nanosheets with a pristine crystal size of 3 similar to 5 nm x 5 similar to 7 nm show the ultrahigh specific capacities of similar to 348 mAh g(-1) and similar to 312.5 mAh g(-1) at charge/discharge current density of 5 A g(-1) and 100 A g(-1), respectively, and over 70% specific capacity still remains after 1000 cycles, while the irregular honeycomb-like alpha-Ni(OH)(2) consisting of nanosheet with a pristine crystal size of 10 similar to 15 nm x 15 similar to 20 nm shows only similar to 260 mAh g(-1) specific capacity at 5 A g(-1) and similar to 150 mAh g(-1) at 100 A g(-1). The ultrahigh electrochemical performances are attributed to the nanoscale and the defective nanostructure of the cathodic deposited alpha-Ni(OH)(2). (c) 2017 Published by Elsevier Ltd.