Novel Co(OH)2 with cotton-like structure as anode material for alkaline secondary batteries

The cotton-like Co(OH)2 (S-Co(OH)2) was successfully synthesized and its electrochemical performance was systematically investigated. S-Co(OH)2 was prepared through the "destruction" of the newly formed colloid Co(OH)2 by the reduction using sodium borohydride. The crystal structure and surface morphology were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Used as an anode material for alkaline secondary batteries, S-Co(OH)2 sample exhibited better cycle stability, higher electrochemical capacity, and higher rate performance than those of conventional β-Co(OH)2. At a discharge current density of 100 mA/g, the initial discharge capacity of S-Co(OH)2 is 549.3 mAh/g and the discharge capacity is still sustained to be 329.2 mAh/g after 100 charge-discharge cycles with a capacity retention of 59.9%.