The magnitude and cycle stability of the charge-discharge capacities of a Li-rich solid-solution layered cathode material, Li[Ni0.18Li0.20Co0.03Mn0.58]O-2, were examined over large voltage windows of 1.2-4.4 V (vs. Li/Li+). Discharging to below 1.5 V activated the cathode material and enabled it to reach larger charge-discharge capacities of over 300 mA h g(-1). Moreover, to retain a high capacity of over 300 mA h g(-1), our original electrochemical precycling treatment (stepwise control of the discharge voltage limit) was applied, resulting in improved stability of the charge-discharge capacity of over 300 mA h g(-1) for at least 35 cycles.