Ternary Co-Ni-B amorphous alloy with a superior electrochemical performance in a wide temperature range

Ternary Co-Ni-B amorphous alloy was synthesized by a chemical reduction method. Used as a negative electrode in the alkaline rechargeable batteries, the as-prepared alloy exhibits an excellent electrochemical performance in the temperature range of -30 to 50 degrees C. Specifically, the discharge capacity after 100 cycles still keeps up at 395.2, 403.7, and 379.1 mAh/g at -15, 0 and 25 degrees C, respectively. Even at a much lower temperature of -30 degrees C, the maximum discharge capacity remains to be 408.3 mAh/g and slowly decays to 317.1 mAh/g after 100 cycles. Moreover, the high-rate dischargeability at 900 mA/g is 29.6% at -30 degrees C. When the temperature increases to 50 degrees C, the discharge capacity of the Co-Ni-B alloy electrode decreases from 675.6 to 283.1 mAh/g after 100 cycles. These properties are very superior to those of conventional hydrogen storage alloy electrodes at the corresponding temperatures. The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and anodic polarization (AP) tests show that the temperature has a crucial effect on the electrochemical kinetics of the Co-Ni-B alloy electrode. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.