Disclosed herein is a composite for the cathode of Li-ion battery comprising: a base active material represented by Li1+y(Nia—COb—Mnc—Yd)O2 wherein Y is at least one selected from Mg, Zn, Al, Ga, Cu, B, Zr, and Ti, y is 0 to 0.5, a is 0.1 to 0.6, b is 0.05 to 0.5, c is 0.25 to 0.8, d is 0 to 0.02, and the sum of a, b, c and d is 1; and a coating on the base active material comprised of a glassy phase containing the components Li2O, B2O3 and LiX in which LiX is at least one of Li2F2, Li2Cl2 and Li2SO4, relative to the total amount of the glassy phase, the mole percent of Li2O is 43% to 75%, the mole percent of B2O3 is 25% to 57%, the mole percent of LiX is from more than 0% to 20%, and the sum of the mole percents of Li2O, B2O3 and LiX is 100%.