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Lithium-Ion Battery Electrolyte Additive to Reduce Capacity Loss and Increase Cycle Life

The US Army seeks a partner to license and commercialize a lithium-ion battery electrolyte additive which reduces initial capacity loss and lengthens useful cycle life at elevated temperatures

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The Technology: 

The US Army has created and patented a non-aqueous electrolyte system containing a new salt additive that, when applied to high-voltage secondary (i.e., rechargeable) batteries, reduces capacity fading throughout the temperature range of lithium-ion cells, but particularly at elevated temperatures. It can be used with industry-standard electrolyte salts found in state-of-the-art lithium electrolytes. It is relatively non-toxic, compatible with existing battery manufacturing processes, and does not add materially to manufacturing cost.

ARL’s new electrolyte system is based on industrially important chemicals, lithium bis(oxalato) borate and lithium oxalyldifluoroborate. These salts reduce first-cycle irreversible loss of charge capacity by about one-half when added to existing lithium-ion cells containing LiPF6 or LiBF4 in carbonate solvent mixtures. Moreover, batteries so-equipped retain as much as 20 percent higher reversible capacity for subsequent cell cycling at elevated temperatures (55º C); it also has higher capacity utilization at lower temperatures. This electrolyte system can be applied to lithium-ion batteries having a carbonaceous anode paired with a wide variety of cathode materials and within a number of different cell formats. This invention can also be generalized to other non-aqueous electrolyte systems.

Benefits: 

• Significant protection against capacity fading for high voltage and high energy density, rechargeable lithium-ion batteries operating at high temperature
• Compatible with lithiated transition metal oxide cathodes, such as LiCoO2, LiNiO2, LiMn2O4; industry-standard electrolyte salts; carbonate solvent mixtures; and carbonaceous anodes
• Drop-in solvent system that does not alter manufacturing process for the production of Li-ion batteries
• Diverse markets such as military, HEV and PHEV automotive, notebook computers, cell phones, and other consumer electronics

The Opportunity: 

• Issued US patent 7,524,579 is available for license
• Potential for collaboration with ARL inventor team

Contacts: