Energetics and stability of cobalt and nickel oxyhydroxides

CMI at Arizona State University conducted the activity for this highlight

Innovation 
Synthesize oxyhydroxides of Ni and Co with high temperature drop solution calorimetry to determine stability and decomposition conditions.

Achievement
Synthesize NiO(OH) and CoO(OH) and measure their enthalpies of formation and decomposition temperatures.

Significance and Impact

  • CoO(OH) aka heterogenite is a common cobalt ore mineral. NiO(OH) is an important battery material.
  • Next steps: synthesis of hexagonal CoO(OH) and y-NiO(OH), calorimetry, and heat capacity measurements.

Hub Target Addressed 
Developing and applying scientific tools to accelerate technology maturation.

composite image of three graphs
Left: Enthalpy of formation from elements of MO(OH), (M = Fe, Co, or NI) with estimated values from other M3+ compounds vs 3rd ionization energy.  Enthalpy measured by high temperature oxide melt drop solution calorimetry. 

Top & Bottom Right: Scanning calorimetry and thermogravimetry showing decomposition conditions for Co and Ni oxyhydroxides as a function of temperature.