NOVELTY - Rechargeable lithium battery (100) comprises: a positive electrode (114) comprising a positive active material; a negative electrode (112) comprising a negative active material; a separator (113) interposed between the positive electrode and the negative electrode; and an electrolyte solution. The separator comprises a porous substrate and a coating layer comprising a ceramic material arranged on at least one side of the porous substrate. The positive active material comprises a lithium metal oxide, and a lithium aluminum phosphate compound (I) on the surface of the lithium metal oxide.    USE - The rechargeable lithium battery is useful for portable electronic equipments.    ADVANTAGE - The rechargeable lithium battery has operation voltage of 4.3 V or higher, and excellent cycle-life at high voltage and high temperature and thickness expansion characteristics at high temperature.    DETAILED DESCRIPTION - Rechargeable lithium battery (100) comprises: a positive electrode (114) comprising a positive active material; a negative electrode (112) comprising a negative active material; a separator (113) interposed between the positive electrode and the negative electrode; and an electrolyte solution. The separator comprises a porous substrate and a coating layer comprising a ceramic material disposed on at least one side of the porous substrate. The positive active material comprises a lithium metal oxide, and a lithium aluminum phosphate compound of formula (Li1+xAlxM2-x(PO4)3) (I) on the surface of the lithium metal oxide.    M = Ti (preferred), Cr, Ga, Fe, Sc, In, Y, Mg or Si; and    x = 0.1 less than or equal to 0.5.    An INDEPENDENT CLAIM is included for making the rechargeable lithium battery, comprising: mixing a lithium raw material, an aluminum raw material, a metal (M) raw material and a phosphate (PO4) raw material in a predetermined ratio to prepare a first product; heating the first product to obtain a second product; pulverizing the second product to obtain a third product; heating the third product to obtain a fourth product; pulverizing the fourth product to obtain a fifth product; precipitating the fifth product to obtain a sixth product; mixing the sixth product with the lithium metal oxide to obtain a seventh product; heating the seventh product to obtain the positive active material; coating the positive active material on a positive collector preparing a positive electrode; providing a separator comprising the porous substrate and the coating layer comprising the ceramic material; combining the negative electrode with the positive electrode and the separator.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of a rechargeable lithium battery.    Rechargeable lithium battery (100)    Negative electrode (112)    Separator (113)    Positive electrode (114)    Battery case (120)    Sealing member. (140)