Non-aqueous electrolyte containing tin or germanium salts and a secondary battery employing the same

High-Temperature, Long-Life Electrolyte Featuring Cathode and Anode Protective Layers via A2MF6 Tin or Germanium Fluoride Additives

This technology utilizes tin or germanium salts represented by the chemical formula A2MF6 (where M is Sn or Ge) as electrolyte additives to form stable protective layers (CEI and SEI) on the surfaces of both the cathode and anode.

Conventional additives like VC and FEC improve high-temperature durability but significantly increase electrical resistance, which degrades battery power output. Furthermore, side reactions between the cathode material and the electrolyte lead to metal ion leaching and battery degradation.

This technology involves adding 0.01 to 1 wt% of A2SnF6 or A2GeF6 (where A is Na, K, NH4, etc.) relative to the total electrolyte volume to form protective layers on the cathode and anode surfaces. Optionally, A2SiF6 silicon salts can be added to create a synergistic effect. It can be applied to electric vehicle battery packs exposed to high summer temperatures, as well as cells for power tools and hybrid vehicles that require high output, extending high-temperature cycle life while avoiding power loss caused by increased resistance.

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Key Features:

• Tin or germanium salts represented by the chemical formula A2MF6, where M is Sn or Ge and A is Na, K, or NH4
• Tin or germanium fluoride additives added to a non-aqueous organic solvent at 0.01 to 1 wt% based on the total electrolyte volume
• Silicon salts represented by the chemical formula A2SiF6, where A is Na, K, or NH4, added in combination with tin or germanium salts
• Electrolyte salts selected from LiPF6, LiBF4, etc., dissolved in a non-aqueous organic solvent at a concentration of 0.5 to 3 mol/L

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