Additives for Anodes

1 Compounds Containing Unsaturated Carbon-Carbon Bond 

In 1992, Sanyo Electric Company found that vinylene carbonate (VC) (1), the most well-known additive at present, can be used as a solvent in lithium secondary batteries [39], 

In 1997, Ube Industries, Ltd. discovered that small quantities of VC can be added for the purpose of suppressing PC decomposition at the graphite anode [42], and in 1998 the same company first became aware of the yellow to brown color of conventional VC and recognized that such colored VC contained considerable amounts of chlorine-based impurities. As a consequence, the same company developed electrolytes containing colorless and highly pure VC with chlorine 

With regard to research on suppression of PC decomposition, in 1993, Shu et al. from the National Research Council of Canada reported that by adding large quantities (0.5 M) of 12-crown-4 ether (2), the formation of complexes of 12-crown-4 ether with Li occurs preferentially to the solvation of Li in PC, which allows for intercalation by suppressing co-intercalation into the graphite layer [44]. 

As described in the report on this work, crown ethers are good chelating reagents for lithium ions. They will compete with electrolyte solvents for lithium ion coordination sites. Furthermore, because of the size of crown ethers, they are too big to be co-intercalated into the graphite layers thus preventing excessive amounts of electrolyte decomposition [44]. However, this concerned complex formation did not necessarily control the SEI. 

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Knoevenagel condensation of malonic acid with heptaldehyde [111-71-7] followed by ring closure, gives the fragrance y-nonanoic lactone [104-61-0] (6) (14). Beside organic synthesis, malonic acid can also be used as electrolyte additive for anodization of aluminum [7429-90-5] (15), or as additive in adhesive compositions (16). 

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