Electrochemistry of Manganese Dioxide in Lithium Nonaqueous Cell: II . X‐Ray Diffractional and Electrochemical Characterization on Deep Discharge Products of Electrolytic Manganese Dioxide

Abstract

X‐ray diffractional and electrochemical characterization of deep discharge products of heat‐treated electrolytic (HEMDs) from 200° to 450°C at 50°C intervals were carried out. XRD examinations of the discharged indicate the core structures were the same regardless of starting HEMDs used. All XRD patterns were indexed and explained using an orthorhombic unit cell having , , and . Possible structures having such a unit cell were discussed based on models which consisted of , , and structures. Electrochemical tests of discharge products indicated the were rechargeable in lithium nonaqueous cell,i.e., 150–180 mAh · g⁻¹ of rechargeable capacity. The reaction mechanism of in the rechargeable region was also examined and shown to be a homogeneous‐phase reaction in a matrix, which anisotropically shrank and expanded within ca. 10% in unit cell volume during the oxidation and reduction, respectively. These XRD and electrochemical studies showed the possibility of rechargeable lithium/manganese dioxide cells.