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 mAh g−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.