Synthesis Methods and Modern Direction in Modification of Nickel Cobaltite and Composite Nanoparticles with its Participation

This paper presents an exhaustive review on the methods of synthesis, properties and modification of Ni, Co-spinels. Among many kinds of catalytic materials and composites with its participation, Ni, Co-spinel attracted great interest, especially as electrode material for electrochemical energy storage/conversion systems, due to its higher theoretical specific capacity than conventional graphite. The main advantages of nickel cobalt spinel and composite materials with its participation are high electrical resistivity and electron conductivity, high rate capability, thermodynamic stability and durability. Peculiarities of the crystal structure of spinels cause such properties. Ni, Co-spinels refer to single-phase triple oxides of the inverse spinel type with two different metal cations. Inverse spinels have considerable electrical conductivity due to the possibility of electron exchange between divalent and trivalent ions in the octahedral position. Due to the presence of such structural features, inverse spinels can be successfully used as electrocatalysts in energy storage/conversion systems. Synthesis approaches of Ni, Co-spinel and composites with its participation include hydrothermal method, microwave synthesis, coprecipitation method, dry synthesis technique and sol-gel method. Establishing a connection between methods and conditions of synthesis, as well as a comprehensive understanding of the methods used to modification the obtained samples, is an important scientific and practical task and an urgent topic for further research in this field.