Technical Competence of Nanodiamond Nanocomposites in Energy Sector (Solar Cells, Fuel Cells, Batteries, Supercapacitors)-State-of-the-Art

This state-of-the-art overview is designed to present indispensable features of nanodiamond nanocomposites and their utilization of advanced energy devices/systems including solar cells, fuel cells, batteries, and supercapacitors. For these systems, nanodiamond nanocomposites have been used in electrodes, electrolytes, membrane-electrode assembly, separators, and other components. Nanodiamond and related nanocomposites have high surface area and unique structural, microstructural, electrochemical, and physical properties to be utilized in efficient devices. Nanodiamond nanocomposites have been designed using sonication/solution preparation, layer-by-layer deposition, chemical vapor deposition, ink deposition, high temperature annealing, doping, solution casting, and in situ polymerization. In this context, various polymeric matrices have been reinforced with nanodiamond to attain the desired design/performance. Accordingly, polypyrrole/nanodiamond and graphene/nanodiamond nanomaterials have been documented for solar cells with photovoltage of ~ 99 mV. Direct methanol fuel cells with platinum/nanodiamond nanocomposites exhibited high electrochemical catalytic activity, high surface area of 80-90 m2·g-1 and power density of 55 mW·cm-2. Silica/nanodiamond and polypyrrole/nanodiamond nanocomposite-based battery designs revealed high capacity of 600-650 mAh/g (1,000 cycles). For supercapacitor electrodes, polyaniline/nanodiamond systems depicted specific capacitance > 640 F·g-1 and capacitance retention > 80%. Future progress in designing efficient nanodiamond nanomaterials may overcome microstructural, conductivity, compatibility, and long-time functioning challenges toward high-performance energy devices.