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Electrochemical storage cell containing a substituted anisole or di-anisole redox shuttle additive for overcharge protection and suitable for use in liquid organic and solid polymer electrolytes

United States Patent

6,045,952
April 4, 2000
View the Complete Patent at the US Patent & Trademark Office
Lawrence Berkeley National Laboratory - Visit the Technology Transfer and Intellectual Property Management Department Website
A electrochemical cell is described comprising an anode, a cathode, a solid polymer electrolyte, and a redox shuttle additive to protect the cell against overcharging and a redox shuttle additive to protect the cell against overcharging selected from the group consisting of: (a) a substituted anisole having the general formula (in an uncharged state): ##STR1## where R.sub.1 is selected from the group consisting of H, OCH.sub.3, OCH.sub.2 CH.sub.3, and OCH.sub.2 phenyl, and R.sub.2 is selected from the group consisting of OCH.sub.3, OCH.sub.2 CH.sub.3, OCH.sub.2 phenyl, and O.sup.- Li.sup.+ ; and (b) a di-anisole compound having the general formula (in an uncharged state): ##STR2## where R is selected from the group consisting of -OCH.sub.3 and -CH.sub.3, m is either 1 or 0, n is either 1 or 0, and X is selected from the group consisting of -OCH.sub.3 (methoxy) or its lithium salt --O.sup.- Li.sup.+. The lithium salt of the di-anisole is the preferred form of the redox shuttle additive because the shuttle anion will then initially have a single negative charge, it loses two electrons when it is oxidized at the cathode, and then moves toward the anode as a single positively charged species where it is then reduced to a single negatively charged species by gaining back two electrons.
Kerr; John B. (Oakland, CA), Tian; Minmin (Kobe, JP)
The United States of America as represented by the United States (Washington, DC)
09/ 045,814
March 23, 1998
The United States has rights in this invention pursuant to Contract No. DE-AC0-76SF00098 between the United States Department of Energy and the University of California for the operation of the Ernest Orlando Lawrence Berkeley National Laboratory.