An excellent rechargeable PP 14 TFSI ionic liquid dual-ion battery.

An ionic liquid dual-ion battery with pure 1-butyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide as the electrolyte was developed, which exhibited a high discharge plateau initiated at 4.4 V, a well-defined capacity of 82 mA h g-1 , an ultrawide charge/discharge potential range of 1.0-5.0 V and a superior stability of ∼100% capacity retention for 600 cycles.