Mechanochemically synthesized amorphous superionic systems for solid-state batteries

Solid-state electrochemical cells of the type Aga-SICI2 are fabricated using mechanochemically synthesized amorphous superionic conductors (a-SICs), AgI-Ag2O-MxOy (MxOy=B2O3, V2O5, CrO3) as electrolytes. The typical value of the conductivity of these systems is in the range 10(-2) to 10(-3) Omega(-1) cm(-1) and the transport number of Ag ions is near unity. The mechanochemically synthesized powders were directly used as electrolytes. Constant load characteristics for various loads confirm the thermodynamic stability and competency of these materials as electrolytes. The cells are discharged at low (Jsimilar to65 muA/cm(2)) and high (Jsimilar to105 muA/cm(2)) drain currents and nominal cell capacities and energy densities were obtained. Nominal cell capacities for all these cells for low current discharge rates were found within 6-7% of the theoretical capacity of Ag/I-2 cell. Whereas, for high discharge rates, similar to 3-4% of the theoretical value. A current density of similar to 500 muA/cm(2) can be drawn safely without any serious polarization. (C) 2002 Elsevier Science B.V. All rights reserved.