Surface-treated cathode active material for aqueous lithium secondary batteries

Long-life aqueous lithium-ion battery using AlF3 surface-coated LiMn2O4 cathode

This technology features an aqueous lithium-ion battery with enhanced cycle stability, utilizing a cathode active material coated with 2 wt% AlF3 on the LiMn2O4 surface, combined with an activated carbon anode and a 1M Li2SO4 aqueous electrolyte.

The flammable organic electrolytes used in conventional lithium-ion batteries pose significant safety risks, such as fire, which has hindered their application in electric vehicles and large-scale energy storage systems. While safe and cost-effective aqueous electrolytes have emerged as a promising alternative, they have been limited by short cycle life due to surface degradation caused by side reactions between the electrolyte and the active material.

This technology uses a metal fluoride coating layer to block direct contact between the aqueous electrolyte and the active material, suppressing surface degradation without affecting the crystal structure or the lithium insertion/extraction process. It achieves a capacity retention of 89.9% after 100 cycles at 1C. Suitable for large-scale energy storage systems and power storage devices where safety is critical, it leverages the benefits of non-flammable aqueous electrolytes while ensuring both long cycle life and high power performance.

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Key Features:

• Cathode active material with 2 wt% AlF3 coating relative to LiMn2O4 weight and an Al/Mn atomic concentration ratio of 542%
• Cathode containing the surface-coated active material along with acetylene black as a conductive agent and polytetrafluoroethylene as a binder
• Battery configuration including an activated carbon anode, a glass filter separator, and a 1M Li2SO4 aqueous electrolyte
• Aqueous lithium-ion battery exhibiting 89.9% capacity retention after 100 cycles at a 1C current rate

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