Danionics A/s

Ningling Rao

Steen Yde-Andersen

Pascal Ge

The instant invention is to an electrolyte consisting essentially of a salt mixture and a solvent mixture. The solvent mixture consists essentially of ethylene carbonate and dimethyl carbonate and the salt mixture consists of 60-90% lithium tetrafluoroborate and 10-40% lithium hexafluorophosphate. A battery comprising this electrolyte and a method of preparing this electrolyte are exhibited.

Lithium salt/carbonate electrolyte system, a method for the preparation thereof, the use thereof and a battery containing the electrolyte system

Modified cokes or blacks suitable as alkali metal intercalation electrodes in electrochemical cells are produced by a method comprising boiling the coke or black in concentrated hydrochloric acid, flushing with distilled water, sonicating the coke or black in acetone, and drying the coke or black at a temperature of 150 to 300&deg; C. The modified cokes and blacks produced by this method show Intercalation capacities up to 50% higher than unmodified cokes and blacks, and maintain the high electrolyte compatibility, rate capability and cyclability of the cokes or blacks.

Preparation of modified cokes and/or blacks

A lithium secondary battery has a negative electrode structure, an electrolyte and a positive cathode structure, the negative electrode structure being of at least 40% by weight of natural flake graphite, having an L,-value of at least 300 nm and/or an L,-value in the range 50-150 nm and an L,-L,-ratio of at least 2, and the electrolyte having at least 10% by weight of propylene carbonate based on the weight of the solvent and salts of the electrolyte system. Natural flake graphite is compatible with propylene carbonate containing electrolytes, thereby forming stable battery configurations.

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Arslev, Denmark

Ningling Rao