Aqueous electrolyte additive for secondary batteries and secondary batteries containing the same

Aqueous electrolyte additive for inducing uniform SEI using a polymer-silica combination

This technology involves adding a combination of metal salts, a hydroxyl-containing polymer (e.g., PEG), and silica with a specific particle size to an aqueous electrolyte. This forms a uniform SEI layer on the anode surface, suppressing dendrite growth and side reactions (hydrogen evolution).

Aqueous secondary batteries have faced issues such as side reactions caused by water decomposition (oxygen/hydrogen evolution), the formation and growth of dendrites on the anode surface during repeated charge/discharge cycles, and the resulting internal short circuits and reduced battery lifespan.

This technology incorporates silica with an average particle size of 0.1–0.5㎛ and a hydroxyl-containing polymer into an aqueous electrolyte at an optimal ratio (silica content: 20 to less than 40 parts by weight per 100 parts by weight of polymer). This imparts non-Newtonian fluid properties, improves metal ion conductivity, and uniformly controls electrodeposition on the anode surface, which can be applied to improve the stability and lifespan of secondary battery anode materials.

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Key Features:

• Aqueous electrolyte for secondary batteries containing metal salts, a hydroxyl-containing polymer, and silica
• Composition where the average particle size of the silica in the electrolyte is between 0.1 and 0.5 micrometers
• Composition where the content of the hydroxyl-containing polymer is 1 to 10 parts by weight per 100 parts by weight of the aqueous electrolyte
• Composition where the silica content is 20 parts by weight or more per 100 parts by weight of the hydroxyl-containing polymer

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