Patent ID: 6495285
Filing Date: 2002-12-17
Classification: H01M,Y02E,Y10T

Abstract:
An electrochemical cell, which comprises:a) a negative electrode which intercalates with an alkali metal; b) a positive electrode comprising an electrode active material which intercalates with the alkali metal; c) a non-aqueous electrolyte activating the negative and the positive electrodes; and d) a phosphonate additive having the formula: (R1O)P(&boxH;O) (OR2) (R3) provided in the electrolyte, wherein R3 is a hydrogen atom and R1 and R2 are selected from the group consisting of: i) one, but not both, of R1 and R2 is a hydrogen atom and the other of R1 and R2 is an organic group containing 1 to 13 carbon atoms; ii) at least one of R1 and R2 is an organic group containing at least 3 carbon atoms and having either: a) a first structure of the type C(sp)â€”C(sp3) directly connected to the â€”OPO2â€” functional group, or b) a second structure of the type C(sp2)â€”C(sp3) directly connected to the â€”OPO2â€” functional group, and wherein when one of R1 and R2 is not of either the first structure or the second structure, then if it is an organic group, it contains 1 to 13 carbon atoms; and iii) at least one of R1 and R2 is an unsaturated inorganic group.