A method of preparing cathode particles using a co-precipitation reaction in a reactor is disclosed. A feed stream (a) containing metal cations is fed into the reactor, and a feed stream (b) containing anions is fed into the reactor, wherein a ratio of the metal cations in the feed stream (a) is continuously changed from A1 at time t1 to A2 at time t2. The feed stream (a) and the feed stream (b) are contacted in the reactor to form precipitated precursor particles, and at least one transition metal component in the particle has a non-linear continuous concentration gradient profile over at least a portion along a thickness direction of the particle.