Improving the high-temperature performances of a layered double hydroxide, [Ni4Al(OH)10]NO3, through calcium hydroxide coatings

In order to improve high-temperature performances, calcium hydroxide was coated onto [Ni4Al(OH)10]NO3 through surface modification or mechanical blending. The existence of Ca(OH)2 was revealed by XRD, and SEM which showed that there are Ca(OH)2-rich blocks in the sample containing 13.0 wt% calcium prepared by surface modification. The addition of Ca(OH)2 can retard the structural transformation from the layered double hydroxide [Ni4Al(OH)10]NO3 to β-Ni(OH)2. In addition, it improves charge/discharge performances and electrochemical reversibility by elevating the oxygen evolution potential, increasing the double layer capacity Cdl and decreasing the charge transfer resistance Rct.