All-solid-state batteries have been desired for the purpose of safety improvement of lithium secondary batteries. In order to improve performance of all-solid-state cells, the formation technique of a favorable interface between active materials and solid electrolytes should be developed. The nanocomposite of the NiS active material and the 80Li(2)S center dot 20P(2)S(5) (mol%) electrolyte was synthesized via a mechanochemical reaction and applied as an electrode to all-solid-state lithium secondary cells. The capacity of the cell with the nanocomposite electrode was larger than that with an electrode prepared by hand-mixing of the active material and the electrolyte powder at both current densities of 64 mu A cm(-2) and 1.28 mA cm(-2). The cell with the nanocomposite showed 360 mAh g(-1) after 50 cycles at 1.28 mA cm(-2) in the potential range from 1.0 to 4.0 V vs. Li. (C) 2008 Elsevier B.V. All rights reserved.