An all-solid state symmetric monolithic sodium ion battery operating at 200 degrees C is described, using NASICON-type electrodes and electrolyte. Na3V2(PO4)(3) is used at both electrodes as the active material while Na3Zr2Si2PO12 stands the role of the Na+ solid electrolyte. Both compositions present order-disorder phase transitions and present decent ionic conductivity properties, 1.5 x 10(-3) S cm(-1) and 1.9 x 10(-4) S cm(-1) at 200 degrees C for Na3Zr2Si2PO12 and Na3V2(PO4)(3). respectively. The full battery (560 mu m in thickness) was assembled in a 10' single step by spark plasma sintering at 900 degrees C. The electrochemical characteristics at high temperature (200 degrees C) were evaluated thanks to a new experimental set-up. The battery operates at 1.8 V with 85% of the theoretical capacity attained at C/10 with satisfactory capacity retention, for an overall energy density of 1.87 x 10(-3) W h cm(-2) and a capacity of 1.04 mA h cm(-2). (C) 2013 Elsevier B.V. All rights reserved.