The sealed Ni/MH batteries with carbon nanotubes (CNTs) in the positive electrodes were assembled. The overall characteristics of Ni/MH batteries were investigated at different charge-discharge cycles at room temperature. The high-rate discharge performance of the Ni/MH battery was improved by the addition of CNTs in the positive electrode. Under high-rate discharge conditions, the batteries with CNTs added in the positive electrodes exhibited much better cycling stability, higher discharge voltage, and high-rate capability. The increase in internal resistance of the batteries with CNTs was lower than that of the batteries without CNTs during charge-discharge cycles. The addition of 0.5 wt.% CNTs was proved a desired amount to modify the batteries performance at the high discharge rates. Too much CNTs contributed no effect in the improvement of overall performance of the batteries. (C) 2004 Elsevier B.V. All rights reserved.