A non-aqueous electrolyte having improved lithium ion conductivity and excellent voltage resistance is provided. A lithium rechargeable battery and a rechargeable battery system including the inventive non-aqueous electrolyte is also provided. The non-aqueous electrolyte includes at least one aromatic compound which is polymerizable at a working electrode potential of 4.2 to 4.5 V when a lithium metal is used as a counter electrode and platinum is used as a working electrode.