Ceramic sheets of Na3V2(PO4)(3) (NVP) with NASICON-related structure have been prepared by tape-casting method. The addition of 60Na(2)O-10Nb(2)O(5)-30P(2)O(5) glass to NVP is demonstrated to enhance markedly the density of the sintered NVP sheet and its electrical conductivity. The best densified NVP sheet with a thickness of a few tens of mu m is obtained by sintering tape-casted NVP added with 5 wt% glass at 920 degrees C, which exhibits a total conductivity of 2.9 x 10(-5) S cm(-1) at room temperature. A Pt vertical bar NVP sheet vertical bar Pt cell works as a tiny solid-state battery with a cell potential of 1.7 V, in which NVP acts as both cathode and anode active materials via redox reactions of V4+/V3+ and V3+/V2+ as well as a Na+ ion conducting electrolyte between the two electrode layers. (C) 2019 Elsevier Ltd. All rights reserved.