Disclosed is a nano-composite material comprising fully separated nano-scaled graphene platelets (NGPs) dispersed in a matrix material, wherein each of the platelets comprises a sheet of graphite plane or multiple sheets of graphite plane and has a thickness no greater than 100 nm and the platelets have an average length, width, or diameter no greater than 500 nm. The graphene plates are present in an amount no less than 15% by weight based on the total weight of the platelets and the matrix material combined. Typically, the nanocomposite is electrically conductive with a bulk conductivity no less than 10 S/cm and more typically no less than 100 S/cm. Highly conductive NGP nanocomposites are particularly useful for fuel cell flow field plate (bipolar plate) and battery electrode applications. Nanocomposites with high NGP proportions can be used in automotive friction plates and aircraft brake components.