Lithium ion rechargeable battery

This invention provides a high-output lithium ion rechargeable battery that can realize high capacitance and, at the same time, can maintain a high discharge voltage and can realize the repetition of large current charge/discharge. The lithium ion rechargeable battery comprises a group of electrodes and a lithium salt-containing nonaqueous electrolyte in which the group of electrodes are immersed. The group of electrodes are formed by stacking or winding a negative electrode material layer containing a material, which can occlude and release a lithium ion, and a positive electrode material layer containing a lithium-containing metal oxide through a synthetic resin separator. The lithium ion rechargeable battery is characterized in that the positive electrode material layer comprises a fluoridized lithium-containing metal oxide as a main component and the separator contains a hydrophilic group. Preferably, the positive electrode material layer comprises a main component of LiNixCoyMnzO2 wherein 0.4 <= x <=1, 0 <= y <= 0.2, 0 <= z <= 0.2, and x + y + z = 1.