Abstract: The subject invention discloses a novel method of providing a binary electrolyte-solvent solution in a solid battery system. A first component of this binary electrolyte solvent system is provided by a material which acts as a plasticizer in the formation of a solid polymeric matrix (separator), composite cathode and/or composite anode, and which also acts as an electrolyte solvent in the completed electrochemical cell. The second component of the binary electrolyte solvent system is an electrolyte solvent, which generally carries the electrolyte salt into the electrolytic cell precursor. The first and second components of the binary electrolyte solvent system mix within the electrolytic cell, dispersing the electrolyte salt throughout the binary electrolyte solvent system. The addition of the electrolyte salt to the electrolytic cell precursor acts to activate the cell precursor, and to form a functional electrolytic cell or battery system.

Abstract: The subject invention discloses a novel electrolyte for a solid battery system. Specifically, an electrolyte solvent of chlorinated diethyl carbonates demonstrate good electrochemical stability in conjunction with specific anode and cathode materials. When used with a propylene carbonate co-solvent, it reduces or eliminates the decomposition of propylene carbonate during the first cycle. It is appropriate with a variety of electrolyte salts, and especially with LiBF.sub.4. Chloro-substituted diethyl carbonates also show good high and low temperature performance in electrochemical cells.