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Bistable Electrochemical Memory Device

IP.com Disclosure Number: IPCOM000093768D
Original Publication Date: 1966-Feb-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 25K

Publishing Venue

IBM

Related People

Dahms, H: AUTHOR

Abstract

This relates to an electrochemical cell and its use as bistable memory device by tailoring its voltage-current characteristic to provide a memory device having two stable voltage states.

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Bistable Electrochemical Memory Device

This relates to an electrochemical cell and its use as bistable memory device by tailoring its voltage-current characteristic to provide a memory device having two stable voltage states.

The drawing shows a bistable characteristic in curve 2. Curve 2 however is obtained by tailoring curve 1 through the use of an adsorbable material. The usual voltage-current characteristic of a redox system is shown in curve 1. The reduction of Ni/++/ on a dropping mercury electrode in a solution of 9N Li I and
1.5 x 10/-3/ M Ni/++/ is an example of a reaction which produces curve 1. The addition of 4 x 10/-5/ M tetra butyl-ammonium-iodide as an adsorbable material changes curve 1 to curve 2.

In a device having the characteristic of curve 2 the choice of the electrode reaction is limited only by a condition. Such condition is that the passage of current through the device does not result in any permanent chemical change in the system i.e. the anode reaction should be equal and opposite to the cathode reaction.

When the electrochemical device is operated at constant current, the device exhibits one out of two stable voltages which differ typically by 0.5 v. Readout of such a device consists in sensing the voltage between the electrodes. This voltage readout is nondestructive and permanent until affirmatively changed. The writing operation consists in changing the voltage between the electrodes as follows. Referring to the graph and curve 2, b...