Investigation of novel cobalt-boron-carbon system as negative material for secondary alkaline battery

A series of novel cobalt-boron-carbon systems have been successfully synthesized by a chemical reduction method with subsequent heat-treatment in the presence of various contents of glucose. The products thus obtained have been investigated as negative electrode materials in KOH aqueous solution. The as-prepared samples are characterized by XRD, ICP, TEM and BET method. It is found that the samples are composed of Co-B particles coated by carbon nanoflakes, which significantly improve their BET surface areas. Electrochemical measurements showed that the Co-B-C electrodes display high discharge capacity, excellent cycle stability and outstanding rate capability. The discharge capacity of the Co-B-C electrode reaches 430.1 mAh g(-1) at the current density of 500 mA g(-1) and it still remains 401.6 mAhg(-1) after 100 cycles, which is attractive compared with other Co-based materials reported before. CV and XRD measurements reveal that the reversible faradic reaction between highly dispersed Co and Co(OH)(2) is dominant for the Co-B-C composites. (C) 2011 Elsevier Ltd. All rights reserved.