Cathode material for polymer batteries and method of preparing same

Abstract

The invention provides a pre-mix of positive electrode material in transportable solid form comprising polymer and solid particles of electrochemically active material and / or electronically conductive additives and a process for preparing a pre-mix positive electrode in transportable solid form. The pre-mix positive electrode material may also comprise an alkali metal salt either dissolved or dispersed in the mixture. The invention also provides making a cathode film from the transportable solid pre-mix of positive electrode material.

Description

FIELD OF INVENTION [0001] The present invention relates generally to polymer batteries and more specifically to the preparation of cathode materials for polymer batteries. BACKGROUND OF THE INVENTION [0002] Lithium / polymer electrolyte batteries are manufactured by superposing three main types of films: a film of metallic lithium, a film of an electrolyte comprising a polymer and a lithium salt, and a film of a positive electrode. Each of these films has a thickness between 5 and 200 μm, for a total thickness of 100 to 300 μm for the elementary film of battery. [0003] The film of positive electrode is typically prepared by coating or extrusion, on a support film or directly on an aluminum foil or metallized plastic film, used as an electrical current collector, a dispersion containing an electrochemically active material such as a transitional metal oxide, carbon black and / or graphite to ensure electronic conduction, a polymer-salt electrolyte to ensure ionic conduction and the mecha...

AI Technical Summary

Benefits of technology

[0009] It is another object of the present invention to provide an improved positive electrode material having dispersed solid content for a lithium polymer battery.

[0010] As embodied and broadly described, the invention provides a pre-mix of positive electrode material in solid transportable form comprising a polymer and solid particles of electrochemically active material and preferably an electronic conductive additive. Preferably, the pre-mix of positive electrode material in solid transportable form comprises a polymer and at least 40% of solid particles of electrochemically active material and electronic conductive additives. Also preferably, t

Problems solved by technology

However, even with a twin screw extruder, the mixing and blending of the various components of positive electrode material is sometime inadequate.

Specifically, the solid particles (active material and electronic conduction additive particles) are not properly mixed and dispersed, resulting in a less homogenous positive electrode material resulting in poor electrochemical performance of the electrochemical cells.

In addition, the use of a twin screw extruder involves high shear events which may potentially degrade the polymer thereby further decreasing the electrochemical performance of the cell during the cycles of charge and discharge.

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