Charge-discharge characteristics of a solid-state Prussian blue secondary cell

A solid-state secondary cell with Prussian blue, i.e., iron (III) hexacyano ferrate (II), as the active material of both the anode and cathode was cons tructed. The Prussian blue was mixed with graphite powder, potassium chlori de and diluted hydrochloric acid to form a thick paste. A Nafion membrane w as used as separator. The charge-discharge performance of the cell was stud ied in galvanostatic mode. For a stabilized cell, the cell voltage was inva riably 1.0 V at half-discharge, whereas it varied from 2.0 to 1.0 V at half -charge depending on the charging rate. Double-step chronopotentiometric ex periments were also carried out to understand the charge-discharge behaviou r. The practical capacity was estimated to be 20 A h/kg from the maximum de liverable current on discharge. The cell was stable up to 60 cycles of char ge-discharge and did not show any significant deterioration. (C) 2000 Elsev ier Science S.A. All rights reserved.